STUDIES IN TRINIDAD AND TOBAGO ORNITHOLOGY HONOURING RICHARD FFRENCH

Edited by Floyd E. Hayes and Stanley A Temple

Occasional Paper # 11 Department of Life Sciences, University of the West Indies, St. Augustine, Trinidad STUDIES IN TRINIDAD AND TOBAGO ORNITHOLOGY HONOURING RICHARD FFRENCH

Editors:

FLOYD E. HAYES Department ofLife Sciences, University of the West Indies, St. Augustine, Trinidad and Tobago

STANLEY A. TEMPLE Department of Wildlife Ecology, University of Wisconsin, Madison, WI 53706, USA

Occasional Paper #11 Department of Life Sciences University of the West Indies, St. Augustine Trinidad

2002 OCCASIONAL PAPERS OF THE DEPARTMENT OF LIFE SCIENCES, UNIVERSITY OF THE WEST INDIES, ST. AUGUSTINE, TRINIDAD

This series has been established for the publication of major papers on the natural history of Trinidad and Tobago. Initiated in 1978 as 'Occasional Papers of the Department of Zoology, University of the West Indies, St. Augustine, Trinidad', the change in name reflects the merger of the Departments of Zoology, Plant Sciences and Biochemistry in 1996. Correspondence concerning manuscripts for publication in the series should be sent to the series editor, Mary Alkins-Koo, Department of Life Sciences, University of the West Indies, St. Augustine, Trinidad and Tobago. Inquiries regarding availability and purcl1ase of publications, listed below, should be addressed to the Secretary, Department of Life Sciences, University of the West Indies, St. Augustine, Trinidad and Tobago.

1. BACON, P. R .. 1978. An annotated bibliography to the fauna (excluding insects) of Trinidad and Tobago 1817-1977.177 pp. 2. ALKlNS, M. E. 1979. The mammals of Trinidad. 75 pp. 3. MOOTOOSlNGH, S. N. 1979. The growth of conservation awareness in Trinidad and Tobago (1765-I 979). 106 pp. 4. BACON, P.R. I 979 (reprinted 1993). Studies on the biological resources ofNariva Swamp, Trinidad. 455 pp. 5. COCK, M . J. W. J 982. The skipper butterflies (Hesperiidae) of Trinidad. Part II. A systematic list of Trinidad & Tobago Hesperiidae. 47 pp. 6. M!CHALSKJ, J. 1988. A catalogue and guide to the dragonflies of Trinidad (order Odonata). 146 pp. 7. RAMNARINE, I. 1989. Cascadu farrning: a manual for the culture of Hoplosternum littorale. 43 pp. 8. SALISBURY, L., AN"D S. DYAL (WITH K. M. DALIP). 1990. A bibliography of zoological research: Department of Zoology 1963-1990. 183 pp. 9. NIESER, N., AND M. ALKINs-Koo. 1991. The water bugs of Trinidad & Tobago. 127 pp. 10. RAMJOHN, C. L., AND S. MAHARAJ (EDS) . 1999. Proceedings of the 23rd Annual Meeting ofthe American Arachnological Society. 50 pp. 11. HAYES, F. E., AND S. A. TEMPLE (EDS). 2002. Studies in Trinidad and Tobago ornithology honouring Richard ffrench. iv + 209 pp.

© Department of Life Sciences, University of the West Indies, St. Augustine, Trinidad, 2002

ISBN: 976-620-167-6

Typeset in Corel WordPerfect 8.0 by Floyd E. Hayes and Carol L. Ramjohn. Printed by Multimedia Production Centre, Faculty of Humanities and Education, University of the West Indies, St. Augustine, Trinidad.

Cover illustration: Colour painting by Robin L. Restall of type specimen (left) and white-throated variant (right) of male Ring-necked Seedeater (Sporophila insularis), described in further detail in pp. 37-44. Financially sponsored by the Center for the Study ofTropica1 Birds, Inc. TABLE OF CONTENTS

TABLE OF CONTENTS ...... 11 PREFACE ...... 1v

RICHARD FFRENCH BACON, PETER R. A biography of Richard ffrench ...... HAYES, FLOYD E., CAROL L. RAMJOHN, Ai\fD NORA JONES. The ffrench connection: contributions of Richard ffrench to T1inidad and Tobago ornithology ...... 7 WORTH, C. BROOKE. Soldado Rock ...... 11

TAXONOMY AND MORPHOLOGICAL VARIATION COLLINS, CHARlES T., AND TAMARA A. ARAYA. Natal pterylosis of two Trinidadian ovenbirds (Fumariidae) ...... 18 HAYES, FLOYD E. Sabre rattling at the lek: morphological variation and its significance in the White-tailed Sabrewing (Campylopterus ensipennis) ...... 23 RESTALL, ROBIN L.. Is the Ring-necked Seedeater (Sporophila insularis) from Trinidad extinct, or is it a cryptic species widespread in Venezuela? ...... 37

FAUNISTICS AND POPULATION ECOLOGY CUFFY, GAIL C. Ecological changes and their impact on avian use of marshes in Caroni Swamp, Trinidad ...... 45 GOCHFELD, MICHAEL Avifauna of a 'reclaimed' wetland: Trinidad's Laventille Marsh in the 1960s...... 54 HAYES, FLOYD E., AND lSHMAELANGELO SAMAD. Avifauna of the 'dragon's teeth': the Bocas Islands, northern Gulf ofParia, between Venezuela and Trinidad ...... 62 MCNAIR, DOUGLAS B., FRED SIBLEY, EDWARD B. MASSI.AH, AND MARTIN D. FROST. Ground-based Nearctic-Neotropic landbird migration during autumn in the eastem Caribbean ...... 86 MURPHY, WILLIAM L. Observations of pelagic seabirds wintering at sea in the southeastem Caribbean ...... 104 WHITE, STEWART A. A mist-netting sh1dy in Guayaguayare and the Victoria Mayaro Forest Reserve, Trinidad, West Indies ...... 111

ECOLOGY, BEHAVIOUR AND CONSERVATION ALEXANDER, GAVIN D. Observations of the Trinidad Piping-Guan, or Pawi (Pipile pipile), in northem Trinidad ...... 119 BERRES, MARK E. Long-term persistence of White-bearded Manakin (Manacus manacus) leks in the Arima Valley of Trinidad, West Indies ...... 131 COLLINS, CHARLES T. Notes on the biology of the Band-mmped Swift in Trinidad ...... 138 HEATH, MYKELA, AND MTKE HANSELL. Weaving techniques in two species of Icteridae, the Yellow Oriole (Icterus nigrogularis) and Crested Oropendola (Psarocolius decumanus) 144 MANOLJS, TIM, AND ALEXANDER CRUZ. Mating and nest-searching behaviour of Shiny Cowbirds associated with different host species in Trinidad and Tobago ...... 155 QUESNEL, VICTOR C. Breeding biology of the B1ack-throated Mango (Anthracothorax nigricollis) ...... 166

11 TEMPLE, STANLEY A. Extinction-prone birds of Trinidad and Tobago: making predictions from theory ...... 180 WHITE, GRAHAM L., AND STANLEY A. TEMPLE. Dickcissels in Trinidad: numbers and impacts on rice crops ...... 194

SHORT COMMUNICATIONS FINCH, DAVIS W. First sight record of Grey Heron (Ardea cinerea) for Tobago, West Indies 199 GOMES, GEOFFREY. Kleptoparasitism of a Great Egret (Ardea alba) by a Common Black-Hawk (Buteogallus anthracinus) ...... 200 MCNAIR, DOUGLAS B., FLOYD E. HAYES, AND GRAHAM L. WHITE. First occurrences of Franklin' s Gull (Larus pipixcan) for Trinidad ...... 201 PETERSEN, WAYNE R., AND DouG McRAE. Noteworthy bird records for Trinidad and Tobago, including first reports of Wood Sandpiper (Tringa glareola) and White-eyed Vireo (Vireo griseus) ...... 204 ROOKS, COURTENAY, AND EDWARD ROOKS. First sight record of Slaty Elaenia (Elaenia strepera) for Trinidad ...... 206 WHITE, GRAHAM L. Mortality of birds due to entanglement in panicles of the grass, Pharus latifolius ...... 208

111 PREFACE

In the polished halls of academia, degrees are their patience while waiting for the final product. everything; in the more practical real world, degrees To assure a high standard of quality, each pa­ are less important. In the school of hfe, it is what per was subjected to peer review from at least two one actually achieves-not what one is trained to researchers whose evaluations and constructive achieve-that matters most. And it is the achievers, criticisms significantly improved each manuscript. regardless of academic qualifications, who we hon­ We thank the following individuals for reviewing our the most for their contributions to humanity. manuscripts (an asterisk represents more than one In recognition of Richard ffrench 's outstand­ manuscript reviewed): John B. Agard, Wayne J. ing contributions to the arts and sciences of Trin­ Arendt*, Peter R. Bacon*, Yasmin Baksh- Comeau, idad and Tobago, both during his 27 years of res­ Gianfranco D. Basili, Alfredo J. Begazo, Keith L. idency (1958-1985) and afterward, we present him Bildstein, Stefan Bodnar, Daniel M. Brooks*, Paul with this collection of studies on the country's A. Buckley, R. Terry Chesser, Charles T. Collins*, ornithology. Gail C. Cuffy, Alfred M. Dufty, Jr. , Jack C. Eitniear*, Although most of the 26 papers in this mono­ Davis W. Finch*, Mercedes S. Foster, Martin D. graph report data obtained exclusively from Trin­ Frost, Kirnbal1 L. Garrett, Michael Gochfeld*, idad and Tobago, one article provides extensive Steven L. Hilty, Leo Joseph, Allan R. Keith*, James data from the British Virgin Islands and Barbados; A. Kushlan, Miguel Lentino, Timothy D. Manolis, the latter locality was home to Richard during 1955- Curtis A. Marantz, Edward B. Massiah, Douglas B. 1958, prior to moving to Trinidad. Two papers in­ McNair*, William L. Murphy*, Michael P. Oatham, corporate data from adjacent portions of Venezuela Robert B. Payne, Richard 0. Prum, Victor C. and one includes observations at sea between the Quesnel, James V. Remsen, Robin L. Restall, Dutch West Indies and Tobago. We hope that Thomas S. Schulenberg, Christopher J. Sharpe, Richard will be pleased with the diversity of sub­ David W. Snow*, Christopher K. Starr*, F. Gary jects, the range of contributing authors (32 includ­ Stiles, Stuart L. Warter, David C. Wege, Graham L. ing eight nationals from Trinidad and Tobago) and White, James W. Wiley, Kevin Winker*, John L. tl1e wealth of new knowledge on the bird life of the Zimmerman and Richard L. Zusi. Neotropics in general, and Trinidad and Tobago in For financially supporting the publication of particular. this monograph, we are grateful to the University of This monograph could not have been pro­ the West Indies at St. Augustine, the Asa Wright duced without the assistance of many individuals Nature Centre, and the Center for the Study of and organisations. We began by soliciting tech­ Tropical Birds, Inc. nical papers from colleagues who had conducted Finally, we thank Miguel Lentino and Carlos A. research on birds in Trinidad and Tobago. We Botero for assistance with translating Spanish ab­ therefore thank the authors for taking the time to stracts, and Edward Rooks for his fine illustrations. write up the results of their research, in some cases decades after the research was conducted, and for Floyd E. Hayes and Stanley A. Temple

lV Pp. l-3 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffTench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. II, 2002.

A BIOGRAPHY OF RICHARD FFRENCH

PETER R. BACON Department ofLife Sciences, University ofthe West Indies, St. Augustine, Trinidad and Tobago

Richard ffrench, 1996 (photo by Edward Rooks)

Richard ffrench was born on 15 September Richard was then conscripted for National 1929 in the town of Aldershot, Hampshire, in Eng­ Service from 1948 to 1950 and saw one year's active land. He received his early education at Blundell's service in Malaya in 1949. After a short b reak, his School, Tiverton, Devon, going on to Ballio1 Col­ Caribbean foray began with an appointment as lege ofOxford University. Here in 1954 he obtained Assistant Teacher at the Lodge School, Barbados, a 2nd Class Honours Degree in Classics, History teachingClassicsfrom 1955to 1958. While there, he and Philosophy (Litterae Humaniores) followed by founded and ran an Arts Club at the school and a Post-graduate Diploma in Education in 1955. directed the Cameo Club Choir in Bridgetown. 2 BACON

He first visited Trinidad and Tobago in 1956 As well as his own research interests in orni­ and soon took up residence when he transferred to thology, Richard ffrench energetical1y promoted St. Peter's School, Pointe-a-Pierre, in 1958. His natural history and conservation activities in Trini­ appointment here was also as an Assistant Teach­ dad and Tobago. He was to become an acknowl­ er, but now responsible for English, Latin, History edged leader in these fields, stimulating others and and Music. Richard was to become Deputy Head­ making a significant contribution to the advance­ master of the school in 1976 and remain in that ment of knowledge and practice. Richard became position untill984 when St. Peter's was closed. In President of the then Trinidad Field Naturalists' addition to a busy schedule of teaching and admin­ Club and Editor for several issues of the Club's istration at the school, he organized and directed journal. He was a founder member of the Asa activities for' the pupils under the President's Wrigllt Nature Centre, becoming President of the Award Scheme (formerly the Duke of Edinburgh's Board in 1969. He was also a founder member and Award Scheme) for about 20 years. His outdoor ac­ Honorary Secretary of the Pointe-a-Pierre Wildfowl tivities under the Scheme led to the coauthoring of Trust. For more than 20 years he served as Orni­ a guidebook to the Nature Trails of Trinidad. He thologist on the Wildlife Conservation Committee, also founded and directed the Orpheus Choir and of the Ministry of Agriculture, where he helped ensured they won several prizes at the national formulate policy on various subcommittees and Music Festivals from 1964 to 1984. provided advice and direction. He was a determined Richard's interest in Caribbean ornithology advocate for bird conservation, preparing reports was kindled in Barbados, but started to blossom for several Govemment institutions, giving lectures soon after his arrival in Trinidad. He became a cer­ at the Institute of Marine Affairs and other agen­ tified Master Bander ('ringer') for the U.S . Fish and cies, organizing and leading field trips and writing Wildlife Service (one of the first in the Caribbean in the press. region) and banded many thousands of birds In 1984, Richard ffrench was honoured by the between 1959 and 1985. His initial interests were Government of the Republic of Trinidad and Toba­ focussed on shorebirds, seabirds (especially terns), go by the award of the Chaconia Medal (Silver) for Scarlet Ibis (Eudocimus ruber) and other wetland achievements in the field of natural science. That species, birds of the offshore islands, Pearl Kite year he also received from H. M. The Queen the (Gampsonyx swainsonii) and Dickcissel (Spiza award of Member of the British Empire for culh1ral americana). For these studies he spent long hours and educational work in Trinidad and Tobago. Fur­ in the field, frequently accompanied and assisted ther to these honours, he was given an Award of by his wife Margaret. Then in 1964 he began work Distinction by the Society for Ca1ibbean Ornithol­ on a handbook covering all the birds of the twin­ ogy for his ornithological work i11 the region. island state. This was to be the first summary text Richard's professional status is confirmed as on the avifauna of a Neotropical region and was an Honorary Life Member of the Trinidad and Tob­ published in I 973. Further issues appeared in 1976, ago Field Naturalists' Club, a Life Member of the 1980 and 1985, with a revised second edition in American Ornithologists' Union, a Life Fellow of 1991. Richard remarked that the book took eight the Royal Society for Protection ofBirds, and mem­ years to write and over 22 years to update! While bership of the Wildfowl and Wetlands Trust, the the book was being compiled, Richard wrote numer­ Scottish Ornithologists' Club, the Neotropical Bird ous bird articles for the Trinidad and Tobago Field Club and the Society for Caribbean Ornithology. Naturalists' Club's journal, the Trinidad Naturalist In I 984, Deputy Headmaster Richard ffrench magazine and the Sunday Guardian newspaper, the became redundant on closure of St. Peter's School. latter attempting to foster public interest in conser­ He then returned to England to take up a position vation . In addition, he produced a paperback on the of Assistant Teacher at Oakley Hall School, Ciren­ more common birds of T1inidad and Tobago in cester, from 1985 to 1986. However, this did not 1986, a book which proved to be even more popular diminish l1is interest or activities in the field of than his larger text. ornithology or his involvement witl1 the Caribbean. Biography ofRichard jfrench 3

He now had more time to birdwatch in Britain and and members of the public, both young and old. became editor of two bird publications focussing The Caribbean is a richer place because Richard on the Gloucester area. ffrench spent so much of his life here. Richard started to lead bird tours to Trinidad Richard currently resides with his wife at and other islands in the Eastern Caribbean, later ex­ Toftingal, Laurieston Road, Gatehouse of Fleet, tending to other Neotropical destinations such as Castle Douglas, Scotland DG7 2BE. Tel/fax: UK Belize, Costa Rica, Ecuador and Venezuela. He also I 557-814601. E-mail: [email protected]. promotes the Asa Wright Nature Centre at the an­ nual UK Bird Fair and other venues and regularly ACKNOWLEDGEMENTS reviews papers on the avifauna of Trinidad and To­ bago for various international journals. Thanks are due to Margaret ffrench, Richard Richard made a significant contribution to orni­ ffrench (unwittingly) and Geoff Gibbs forproviding thology in Trinidad and Tobago, but also to the much of the background detail for this Biography, culture and development of these islands. His has and to C. T. Collins, W. L. Murphy and R. Restall been a positive influence on many local naturalists for reviewing the manuscript. Pp. 4-10 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. I I, 2002.

THEFFRENCH CONNECTION: CONTRIBUTIONS OF RICHARD FFRENCH TO TRINIDAD AND TOBAGO ORNITHOLOGY

FLOYD E. HAYES 1, CAROL L. RAMJOHN 1 AND NORA JONES2 1Department ofLife Sciences, University of the West Indies, St. Augustine, Trinidad and Tobago 2 /06 -18th AvenueS. E., Calgmy, AB T2G JK8, Canada

ABSTRACT.-Richard ffrench resided in Trinidad and Tobago from 1958-1985, and has continued to be actively involved in the country's ornithology. During 1961-2000, Richard published 96 books, chapters, articles or notes, almost exclusively on the birds of Trinidad and Tobago. Two editions of A Guide to the Birds of Trinidad and Tobago ( 1973 and 1991) comprise his major ornithological conttibutions, which account for 60% of his citations in the Science Citation Index. His 63 technical publications, which included 1267 pages, on Trinidad and Tobago ornithology comprised 26% of all pub­ lications and 37% of all pages published on the country's ornithology during this period. Other major contributions include his initiation of the annual Christmas Bird Count in Trinidad and the formation of the Trinidad and Tobago Rare Bird Committee.

RESUMEN .-Richard ffrench fue residente en Ia Trinidad y Tobago desde 1958-1985, y ha continuado estando involucrado activamente e11 Ia ornitologia de este pais. Durante 1961-2000, Richard publico 961ibros, capftulos, articulos yuotas, casi exclusivamente sobre las aves de Trinidad y Tobago. Las dos ediciones de A Guide to the Birds of Trinidad and Tobago (1973 y 1991) constituyen sus mayores contribuciones orni­ tol6gicas, representando el 60% de sus citas en el Science Citation Index. Sus 63 publicaciones tecnicas, que incluyen 1267 paginas, sobre Ia ornitologia de Trinidad y Tobago constituyen 26% de todas las pubhcaciones y 37% de todas las piiginas publicadas sobre Ia omitologia del pais durante este periodo. Otras contribuciones mayores incluyen su iniciaci6n del Christmas Bird Count anual en Trinidad y Ia formaci6n del Trinidad and Tobago Rare Bird Committee.

KEY WORDS.-bibliography, ornithological contributions, Richard ffrench, Trinidad and Tobago

Perhaps more so than any other field of sci­ birds in the field, write dozens of technical and ence, ornithology has been richly endowed by the popular articles on birds, and produce one of the contributions of amateurs lacking higher degrees most scholarly field guides ever written on an and working in unrelated professious. Some ama­ avifauna. In this paper we summarise and quan ­ teurs have contributed more to our knowledge of titatively analyse the contributions of Richard birds than have many professionals. One such in­ ffrench to the ornithology of Triuidad and Tobago, dividual is Richard ffrench, who never earned a uni­ which greatly overshadow those of any other versity degree in biology or worked as a profes­ individual dming the latter half of the twentieth sional biologist, yet managed to band thousands of century.

4 Ornithological Contributions ofRichard ffrench 5

METHODS RESULTS AND DISCUSSION

We compiled a bibliography (arranged in Richard resided in Trinidad and Tobago from chronological order by year and alphabetical order 1958-1985, and has continued to be actively in­ by author within year) of the published writings volved in the countTy's omithology. During the (excluding newspaper articles) of Richard ffrench period of 1961-2001 , Richard published 96 books, and review his contributions to Trinidad and Tob­ chapters, articles or notes, almost exclusively on ago ornithology. the birds of Trinidad and Tobago (see Bibliography To compare Richard's contributions to those below). Of these, 60 could be considered original of his colleagues, we also compiled a comprehen­ scientific contributions published in technical jour­ sive bibliography of technical references (excluding nals. Most of these (44) were published in the newspaper, newsletter and magazine articles) on semiteclmical Journal of the Trinidad and Tobago Trinidad and Tobago ornithology up through 2000, Field Naturalists' Club (several different names . aud compared the number of publications and num­ used), of which several issues were edited by Rich­ ber of pages published by Richard ffrench with ard. Thirteen articles were published in internation­ those of other authors on T!inidad and Tobago al ornithologicaljoumals, including Auk (two), Co­ ornithology. As for local (Trinidad and Tobago) tinga (two), Ibis (two), Journal of Field Ornithol­ journals, we included articles from Living World ogy (one), Living Bird (two), Ornithological (Journal of the Trinidad and Tobago Field Nat­ Monographs (one) and Wilson Bulletin (three). uralists' Club and its predecessors) and Tropical Three articles were published in broader, regional Agriculture, but not from Bellbird, Bulletin of the scientific journals, including Biological Journal of Trinidad and Tobago Field Naturalists' Club, or the Natural History Society, University of the West Trinidad Naturalist. We included only public­ Indies (one) and Caribbean Journal of Science ations dealing exclusively or nearly exclusively with (two). birds. Articles on finding birds and reviews of The bulk of Richard's original contributions books and albums were excluded, but two compre­ comprised distributional records of birds, including hensive books on finding birds in Trinidad and many species recorded for the first time in Trinidad Tobago were included. We counted the two ed­ and Tobago. As a Master Bander for the United itions, but not the minor revisions, of Richard's States Fish and Wildlife Service, some of Richard's technical field guide {see below) as separate pub­ most noteworthy birds were captured and banded. lications, and also included his photographic guide In addition to his OWll observations, these reports (see below). often included the observations of visiting birders We also examined the Science Citation h1dex and ornithologists. All records were critically evalu­ (SCJ) from 1960-1999 to determine the number of ated, with many rejected for lack of evidence. Since times other scientists cited publicati011s (categor­ moving to Trinidad and Tobago in 1958, Richard ised as field guide or other) by Riclmrd ffrench. The has been the primary compiler of information on the SCI is used by researchers to trace subsequent status and distribution of the country's birds. citations of a previously published paper. The SCI During his 27 years of residency in Trinidad scans articles only in the most widely circulated and Tobago and subsequently during his frequent technical journals, and occasionally in books; as a trips to the country as a bird tour leader, Richard consequence, it underestimates the number of travelled extensively throughout the country, pri­ times a publication is cited. Nevertheless, it is a marily observing but also banding birds. His explor­ useful tool for evaluating the influence of authors, ation of the various islets of the country, including journals and specific publications. Because the the major Bocas Islands (Chacachacare, Huevos most important authors and publications are cited and Monos), Soldado Rock, Saut D'Eau, Little more often, institutions routinely rely on the SCl to Tobago and St. Giles, provided a wealth of new evaluate scientists applying for employment, tenure data on the abuudance, breeding, moult and mor­ and promotion. phometries of the birds inhabiting these islands. 6 HAYESET AL.

The avifaunas of wetlands, especially the water­ and weight, food, nesting and behaviom of most birds of coastal mudflats at Pointe-a-Pierre and the species, plus an extensive bibliography, in a format mangroves of Caroni Swamp, were studied in­ more akin to a manual than a typical field guide. tensively. Richard and his wife, Margaret, also The major weakness of the field guides was the lack conducted a thorough study on the Jandbirds of of illustrations for many species of birds, though Grafton Estate in Tobago. hopefully this shortcoming will be corrected in the Many articles presented data on the natural next edition. history of individual species, focussing primarily Richard's efforts to stimulate an iuterest in on their breeding biology. The most intense studies birds among the general public resulted in 22 artic­ were conducted on the Scarlet lbis (Eudocimus les published in Trinidad Naturalist from 1976- ruber), Pearl Kite (Gampsonyx swainsonii), Brown 1985, about 80 articles published in The Sunday Noddy (Anous stolidus), Yellow-bellied Seedeater Guardian from 1982-1985, and the publication in (Sporophila nigricollis) and Dickcissel (Spiza am­ 1986 of Birds of Trinidad and Tobago (MacMillan ericana). Press Limited, London), which included photo­ Richard organised the first Christmas Bird graphic illustrations (mostly taken by Richard) of Count in Trinidad (1969) and was the principal the more common species of birds in Trinidad and compiler of annual counts from 1969-1975 and 1981- Tobago. 1983. Although the results of these counts were In 1995, Richard formed the Trinidad and Tob­ originally published in American Birds, Richard ago Rare Bird Committee, which comprised seven published a compilation of data from the 1969-197 5 members whose primary purpose was to evaluate and 1981-1983 counts. submitted records of birds rarely recorded or pre­ ln addition to his original scientific contri­ viously unrecorded from the country. Richard has butions, other mticles published in Journal of the served as a member of the committee until present Trinidad and Tobago Field Naturalists' Club in­ and has published two preliminary reports of the clude a note on conservation news, a bibliography committee's actions. The 1996 publication of sepa­ of Trinidad and Tobago omithology, a summary of rate cl1ecklists on the birds of Trinidad and Tob­ recent taxonomic changes in Trinidad and Tobago ago, respectively, culminated indirectly from his birds, an analysis of the omithological history of involvement with the committee. Trinidad and Tobago, three book reviews, one al­ In addition to his ornithological contributions, bum review and a comprehensive index. Richard co1Iaborated with Peter R. Bacon in the Richard's intimate knowledge of Trinidad and publication of two non-scientific books. The Wild­ Tobago's avifauna enabled him to publish A Guide life Sanctuaries of Trinidad and Tobago , pub­ to the Birds of Trinidad and Tobago in 1973 (Liv­ lished in 1972 (Ministry of Agriculture, Lands and ingston Publishing Company, Wynnewood, PA). Fisheries, Port of Spain), included four chapters This guide was a major advancement above G. A. authored or coauthored by Richard. The Nature C. Herklots' The Birds of Trinidad and Tobago, Trails of Trinidad was published in 1982 (S. M. published in 1961 (Collins, London). Minor re­ Publications, Port of Spain) and revised by Victor visions were published in 1976, 1980 and 1985 Quesnel in 1992 (same publisher). Richard's con­ (Harrowood Books, Newtovm Square, P A), and a tributions to both books were based on his orni­ supplement was published privately in 1988. A thological exploration. completely revised second edition was published in How do Richard's contributions compare with 1991 (Cornell University Press, Ithaca, NY). The those of his colleagues? During the period of 1961- two editions of this field guide, illustrated by John 2000, Richard produced 63 'technical publications' P. O'Neill and Don R. Eckelbeny, represent Rich­ on Trinidad and Tobago ornithology (see Biblio­ ard's chief contributions to Trinidad and Tobago graphy below; 'technical papers' exclude articles in ornithology. A third edition is currently being pre­ Trinidad Naturalist, non-bird articles and reviews), pared. The primary asset of Richard's field guides which comprised about 26% of all technical was the extensive presentation of data on body size publications during the pe1iod. His technical publi- Ornithological Contributions ofRichard jji·ench 7

TABLE I. Science Citation Index citations of public­ Field Nat., J. Trin. Field Nat. Club 1961:9-10. ations by Richard ffrench from 1965-1999. FFRENCH, R. P. 1963. Bulwer's Petrel in Trinidad, West Indies. Auk 80:379. Field Other FFRENCH, R. P _ 1965a. Notes on the avifauna of Period guide publications Grand Fond, Monos, May 1964. J. Trin. Field 1965-1969 6 Nat. Club 1965:28-36. 1970-1974 13 FFRENCH, R. P. 1965b. Check-list of the birds of 1975-1979 15 2 Grand Fond Valley and Bay. J. Trin. Field Nat. 1980-1984 16 3 Club 1965:37-39. 1985-1989 20 6 FFRENCH, R. P. 1965c. Notes on the avifauna of 1990-1994 12 17 Grand Fond, Monos, Aug 1964. J. Trin. Field 1995-1999 10 2 Nat. Club 1965:41-50. FFRENCH, R. P. 1965d. Review [of Bird songs of the tropics]. J. Trin. Field Nat. Club 1965:51-52. cations comprised 1267 pages, which account for FFRENCH, R. P. 1965e. Some unusual habits of Little about 37% of all pages published during this per­ Blue Herons. Carib. J. Sci. 5:89. iod. FFRENCH, R. P. 1965f. The nesting behaviour of the During the 35-year period of 1965-1999, Rich­ Yellow-bellied Seedeater. Carib. J. Sci. 5:149- ard's publications were cited 123 times in the SCI, 156. for an average of3 .5 citations per year (Table 1). Of FFRENCH, R. P., AND C. T. COLLINS. 1965. Royal and these, the majority (60%) referred to the field guide, Cayenne tems breeding in Trinidad, West In­ which obviously represented the most imp01tant dies. Auk 82:277. publication. Althougl1 the number of citations is FFRENCH, R. P. 1966a. The utilization of mangroves not high by the standards of North American and by birds in Trinidad. Ibis 108:423. European scientists, it must be recalled that Richard FFRENCH, R. P. 1966b. The Scarlet Ibis. Bioi. J. Nat. lacked a fonnal scientific training, conducted re­ Hist. Soc. Univ. West Indies. I :30-36. search in an area where few scientists worked, and Fl'RENCH, R. P., Al'D M. FFRENCH. 1966. Recent published most of his scientific papers in a rela­ records of birds in Trinidad and Tobago. Wil­ tively obscure local journal. son Bull. 78:5-11. Richard ffrench's substantial contributions to FFRENCH, R. P. 1967a. The avifauna of Huevos Trinidad and Tobago ornithology clearly qualify Island. Trin. Field Nat. Club J. 1967:19-24. him as the leading authority on the country's avi­ FFRENCH, R. P. 1967b. Checklist of the birds of fauna during the latter half of the twentieth century. Huevos and Chacachacare. Ttin. Field Nat. In recognition of his contJibutions to the omith­ Club J. 1967:25-27. ology of the region, the Society of Caribbean Or­ FFRENCH, R. P. 1967c. The avifauna ofChacacha­ nithology bestowed an A ward of Distinction upon care Island. Trin. Field Nat. Club J. 1967:45-52. Richard during a meeting in Trinidad in 1995. FFRENCH, R. P. 1967d. The Dickcissel on its winter­ ing grounds in Trinidad. Living Bird 6:123-140. ACKNOWLEDGEMENTS FFRENCH, R. P _ 1969a. Fmiher notes on the avifauna ofChacachacare Island. Trin. Field Nat. Club J. We thank R. ffrench for unwittingly assisting 1969: I 0-12. us with the compilation of his bibliography, and J. FFRENCH, R. P. 1969b. The avifauna of Saut D'Eau B. Agard, J. C. Eitniear, and W. L. Murphy for re­ Island. Trin. Field Nat Club J. 1969:16. viewing the manuscript. FFRENCH, R. P. 1969c. Conservation news. T1in. Field Nat. Club J. 1969:22-24. BIBLIOGRAPHY OF RICI--IARD Fl'RENCH FFRENCH, R. P. 1969d. Two noteworthy bird re­ cords. Trin. Field Nat. Club J. 1969:29. FFRENCH, R. P. 1961. The Red-billed Tropicbird. DINSMORE, J. J., AND R. P. FFRENCH. 1969. Birds of 8 HAYESET AL.

St. Giles Islands, Tobago. Wilson Bull. 81:460- 1973:74-79. 463. T!KASINGH, E. S., Pu"\ID R. FFRENCH. 1973. First record FFRENCH, R. P., AND F. HAVERSCHMIDT. 1970. The of the Ovenbird i11 Trinidad, West Indies. Wil­ Scarlet Ibis in Surinam and Trinidad. Living son Bull. 85:86. Bird 9:I47-I65. FFRENCH, R. P. 1975a. Some noteworthy bird re­ LILL, A., AND R. P. FFRENCI-I. I 970. Nesting of the cords from Tobago. J. Ttin. Tob. Field Nat. Plain Antvireo Dysithamnus mentalis andrei Club 1975:5-11. in Trinidad, West Indies. Ibis I I2:267-268. FFRENCH, R. P. I 975b. The hospitable hog plum. J. f"FRENCH, R. P. I 971. A list of recently published Trin. Tob. Field Nat. Club 1975:80-81. articles on the avifauna of Trinidad & Tobago. FFRENCH, R. 1975c. A bird visitor from Finland. J. Trin. Field Nat. Club J. 1971:52-54. Trin. Tob. Field Nat. Club 1975:85-86. BACON, P.R., AND R. P. FFRENCH (EDS.). 1972. The FFRENCH, R. 1976a. The birdman's paradise. Ad­ wildlife sanctuaries of Trinidad and Tobago. venture in the Caroni wonderland. Trin. Nat. Ministry of Agriculture, Lands and Fisheries, 1(2):22-31. Port of Spain. 80 pp. FFRENCH, R. 1976b. The Cocrico. National bird or FFRENCH, R. P. 1972a. Little Tobago. Pp. 36-39 in pest? Trin. Nat. 1(5):50. The wildlife sanctuaries ofTrinidad and Toba­ FFRENCH, R. 1977a. Some interesting bird records go (P.R. Bacon and R. P. ffrench, eds.). Min­ from Trinidad & Tobago. Living World (J. istry of Agriculture, Lands and Fisheries, Port Field Nat. Club Trin. Tab.) 1977:9-10. of Spain. FFRENCH, R. 1977b. Birds of the Caroni Swamp and FFRENCH, R. P. 1972b. Saut D'Eau Island. Pp. 40-42 marshes. Living World (J. Field Nat. Club Trin. in The wildlife sanctuaries of Trinidad and Tob.) 1977:42-44. Tobago (P. R. Bacon and R. P. ffrench, eds.). !'FRENCH, R. 1977c. King of the woods. Trin. Nat. Ministry of Agriculture, Lands and Fisheries, 1(9):27. Port of Spain. FFRENCH, R. 1977d. The beautiful Bos'n Bird (Red­ FFRENCH, R. P. 1972c. Soldado Rock. Pp. 42-46 in billed Tropicb1rd). Trin. Nat. 1 (I 0):30-31. The wildlife sanctuaries of Trinidad and Toba­ FFRENCH, R. 1977e. The chuckle in the garden. Trin. go (P.R. Bacon and R. P. ffrench, eds.). Min­ Nat. 1(11):49. istry of Agriculture, Lands and Fisheries, Port FFRENCH, R. 1977f. Jumbie bird, friend or foe. Trin. of Spain. Nat. I (12):34-35. FFRENCH, R. P. 1972d. St. Giles Islands. Pp. 63-66 in !'FRENCH, R. 1978a. Hermit of the woods. Trin. Nat. The wildlife sanctuaries of Trinidad and Toba­ 2(1 ):24-25. go (P. R. Bacon and R. P. ffrench, eds.). Min­ FFRENCH, R. 1978b. Our Osprey-a cautionary tale. istry of Agriculture, Lands and Fisheries, Port Trin. Nat. 2(2):22. of Spain. FFRENCH, R. 1978c. What does he say? Trin. Nat. PYKE, S., P. R. BACON, R. P. FFRENCH, AND B. S. 2(3):32-33. RAMDIAL.l972. Central Range Wildlife Sanctu­ FFRENCH, R. 1978d. The ubiquitous Sugarbird. Trin. ary. Pp. 20-24 in The wildlife sanctuaries of Nat. 2(4):28-29. Trinidad and Tobago (P. R. Bacon and R. P. FFRENCH, R. 1978e. The wildest place of all. Trin. ffrench, eds.). Ministry of Agriculture, Lands Nat. 2(6):28-31, 34-35. and Fisheries, Port of Spain. FFRENCH, R. l978f. Bird news. Trin. Nat. 2(6):45. FFRENCJ-I, R. I 973a. A guide to the birds of Trinidad FFRENCI-I, R. I 979a. More records of rare birds in and Tobago. Livingston Publishing Company, Trinidad and Tobago. Living World (J. Trin. Wynnewood, PA. 470 pp. (revised editions Tab. Field Nat. Club) 1978-1979:25-26. published by Harrawood Books, Newtown FFRENCH, R. 1979b. Bird in the manger. Trin. Nat. Square, PA, in 1976, 1980 and 1985) 2(4):25, 29. FFRENCH, R. P. l973b. Dubious bird records for FFRENCH, R. 1979c. Out of the frying pan into the Trinidad and Tobago. J. Trin. Field Nat. Club fire. Trin. Nat. 2(8):33. Ornithological Contributions of Richard ffrench 9

FFRENCH, R. 1979d. My f1iend, the Noddy. Trin. FFRENCH, R. 1986c. Christmas counts of birds in Nat. 2(11):12. Trinidad 1969-1975 and 1981-1983. L1ving FFRENCH, R., AND M. FFRENCH. 1979. The birds of World (J. Trin. Tob. Field Nat. Club) 1985- Grafton Estate, Tobago. Living World (J. Trin. 1986:12-18. To b. Field Nat. Club) 1978-1979:19-24. FFRENCH, R. P. 1986d. Birds of Trinidad and Toba­ FFRENCH, R. 1980a. Miracles of the forest. Trin. Nat. go. MacMillan Press Limited, London. 87 pp. 3(2)27-28. FFRENCH, R. 1988a. Supplement to A guide to the FFRENCH, R. 1980b. Marathon birds. Trin. Nat. birds of Trinidad and Tobago. Published by 3(3):59-60. the author. 24 pp. FFRENCH, R. 19 81 a. Some recent additions to the FFRENCH, R. 1988b. Peppershrike song. Living avifauna of Trinidad and Tobago. Living World (J. Trin. Tob. Field Nat. Club) 1987- World (J. Tri11 . Tob. Field Nat. Club) 1981- 1988:46. 1982:35-36. FFRENCH, R. 1988c. [Review of] A birder's guide to rFRENCH, R. 198lb. Brief notes on birds. Living Trinidad and Tobago. Living World (J. Ttin. World (J. Trin. Tob. Field Nat. Club) 1981- Tob. Field Nat. Club) 1987-1988:48. 1982:46-47. RAMCHARAN, E. K. , AND R. P. FFRENCH. 1988. The FFRENCH, R. 1981 c. Rarities. Trin. Nat. 3(7):6. status and distribution of wetland-dependent FFRENCH, R. !981d. The Bellman of the woods. Trin. birds in Trinidad. Living World (J. Trin. Tob. Nat. 3(1 0): 15. Field Nat. Club) 1987-1988:36-40. FFRENCH, R. 1981 e. The Washerwoman. Trin. Nat. FFRENCH, R. 1990. The birds and other vertebrates 3(8):24-25. of Soldado Rock, Trinidad. Living World (J. FFRENCH,R. P. 1982a. The breeding of the Pearl Kite Trin. Tob. Field Nat. Club) 1989-1990:16-20. in Trinidad. Living Bird 19:121-131. FFRENCH, R. 1991 a. A guide to the birds of Trinidad FFRENCH, R. 1982b. Johnny Jump-up. Trin. Nat. and Tobago. 2nd ed. Come]] University Press, 4(1):42. Ithaca, NY. 426 pp. FFRENCH, R. P., AND P.R. BACON. 1982. The nahtre FFRENCH, R. 1991 b. Synchronous breeding and trails of Trinidad. S. M. Publications, Port of moult in the Brown Noddy tern on Soldado Spain. 85 pp. Rock, Trinidad. Living World (J. Trin. Tob. FFRENCH, R. 1983a. Further notes on the avifauna of Field Nat. Club) 1991-1992:39-41. Trinidad & Tobago. Living World (J. Trin. FFRENCH, R. 1991 c. [Review of] Birds of the eastern Tob. Field Nat. Club) 1983-1984:32-34. Caribbean. Living World (J. Trin. Tob. Field FFRENCH, R. !983b. Recent changes in the "official" Nat. Club) 1991-1992:56. designations of certain Trinidad birds. Living FFRENCH, R. 1991 d. Index for J oumal of Trinidad World (J. Trin. Tob. Field Nat. Club) 1983- and Tobago Field Naturalists' Club 1956-1989. 1984:59. Living World (J. Trin. Tob. Field Nat. Club) FFRENCH, R., AND T. MANOLIS. 1983. Notes on some 1991-1992:59-65. birds of Trinidad wetlands. Living World (J. FFRENCH, R. 1993. Further records of birds on Trin­ Trin. Tob. Field Nat. Clltb) 1983-1984:29-31. idad and Tobago. Living World (J. Trin. Tob. FFRENCH, R. P. 1985a. Changes in the avifauna of Field Nat. Club) 1993-1994:28-31. Trinidad. Omithol. Monogr. 36:986-991. FFRENCH, R. 1996a. Checklist of the birds of Trin­ FFRENCH, R. 1985b. A new look at our Scarlet Ibis. idad. Asa Wright Nature Centre, Arima, Trin­ Trin. Nat. 6(5):30-32. idad. 22 pp. FFRENCH, R. 1986a. Movements of seabirds off FFRENCH, R. 1996b. Checklist of the birds of Toba­ Crown Point, Tobago. Living World (J. Trin. go. Asa Wright Nature Centre, Arima, Trin­ Tob. Field Nat. Club) 1985-1986:5-8. idad. 14 pp. FFRENCH, R. l986b. Additional notes on the birds of FFRENCH, R. 1996c. [Review of] Birds ofTrinidad & Trinidad and Tobago. Living World (J. Tlin. Tobago: a photographic atlas. Living World (J. Tob. Field Nat. Club) 1985-1986:9-11. Trin. Tob. Field Nat. Club) 1995-1996:39-40. 10 HAYESET AL.

FFRENCH, R. l 998a. A review of the ornithology of ords from Trinidad & Tobago in 1997. Cotinga Trinidad and Tobago 1950-1985. Living World 9:84-85. (J. Tri11. Tob. Field Nat. Club) 1997-1998:3-7. FFRENCH , R., AND G. WHITE. 1999. Verification of FFRENCH, R. 1998b. Doubtful 01igin in some bird rare bird records from Trinidad & Tobago. Co­ species recorded from T1inidad & Tobago. Liv­ tinga 12:80-82. ing World (J. Trin. To b. Field Nat. Club) 1997- FFRENCH , R. 2000. Possible intra-regional bird mi­ 1998:8-12. gration in Trinidad and Tobago. Living World FFRENCH, R. 1998c. Some outstanding problems in (J. Trin . To b. Field Nat. Club) 1999-2000:27-31. the ornithology of Trinidad and Tobago. Liv­ FFRENCH, R., AND M. FFRENCH. 2000. Comparative ing World (J. Trin. Tob. Field Nat. Club) 1997- abundance of birds in Trinidad's Northern 1998:13-16. Range. Living World (J. Trin. Tob. Field Nat. FFRENCH, R. 1998d. A reconsideration of some Club) 1999-2000:32-35. Caprimulgids on Trinidad and Tobago. Living HAYES, F. E., N. A. TRIMM, B. SANASIE, AND R. P. World (J. Trin. Tob. Field Nat. Club) 1997- FFRE."'CH. 2000. Breeding biology ofthe White-tailed 1998:17-19. Sabrewing at Tobago, West Indies. J. Field FFRENCH, R., AND F. E. HAYES. 1998. Rare bird rec- Omithol. 71:597-605. Pp. 11-17 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. 11, 2002.

SOLDADO ROCK1

C. BROOKE WORTH2 1excerpted from chapter 10, pp. 100-115, of A Naturalist in Trinidad (1967. J. B. Lippincott Company, Philadelphia, Pennsylvania. 291 pp.) 2deceased

Richard and Margaret ffrench led us to our to record data in the proper notebook as items were adventures on Soldado Rock and a new virus for called out. Trinidad. Richard is a tall, thin, lively Enghshman Formerly Margaret ffrench had been No. 1 who teaches in a boys' school maintained by one assistant in all these tasks. Occasionally Richard of the big oil companies for children of its em­ would persuade one or another of his slightly in­ ployees in Point[ e)-a-Pierre, near San Fernando, in terested friends to help, but they did it more for southwest T1inidad. Somehow he became interest­ adventure than out of understanding. Now TRVL ed in birds. Having done so, he made it his duty to [Trinidad Regional Virus Laboratory] became a real do something constructive about it. Through a pro­ partner in the enterprise, for the first trip was so cess of devoted self-education, he finally became unexpectedly profitable that Soldado was added as proficient enough to be given a permit by the U. S. a fixture to our program. Fish and Wildlife Service to band certain birds. Soldado (Soldier) Rock lies about ten miles That agency, in tum, was eager to find volunteer west of the southwestern tip of Trinidad, rising cooperators in the tropics who would trap and some hundred and forty feet above sea level from band migrants from North America. The pos­ the shallows of the Gulf of Paria. To get there, we sibilities in Trinidad included ducks, gulls, terns, would drive from Port-of-Spain, pick up Richard shore birds, Dickcissels and a few species of war­ and anyone else from Point[e]-a-Pierre who was bler. Richard ffrench was a natural for the F. and W. going, and then continue tl1rough oilfields within people, just as they provided the exact outlet he the jungle to Cedros. Here the boatman was waiting wanted for himself. He selected Dickcissels, shore­ with his small but heavily built wooden craft, birds and tems as his specialties. equipped with a powerful outboard engine. Now we I believe that Tommy [Aitken] met Richard at a lugged load after load of needed equipage across meeting of tl1e Trinidad Naturalists' Society [ac­ the beach, sometimes standing in water above our tually the Trinidad Field Naturalists' Club at the knees to heave heavier articles on board. time]. Anyhow, tales of tern banding on Soldado Off we would chug, the motor as likely as not Rock fired Tommy's strenuous knock-yourself-out conking out from time to time. The rock looked tiny instincts, and Wil Downs responded with equal at first- as it really is, covering only about two acres muscle flexing when a joint venture was proposed. on the map. (Its actual surface is much greater than As for Richard, he welcomed not only the thought that because of its steep sides.) But as we neared it, of bird-minded companions but also the extra pairs after an hour, concepts of tininess went up the of hands. Sooty Terns and Brown Noddies on the spout: now it was formidable and forbidding. All Rock had to be caught first- whether as flying around its perimeter lay great fallen blocks of stone, adults or scurrying chicks- but it was not simply a against which waves crashed in foaming fury. As if matter of banding and letting them go. Each bird to head us off, flocks of grotesque Brown Pelicans must also be weighed; certain measurements must leapt into the air and set up a patrol round and be taken; stage of molt or lack of molt had to be round the rock near sea level. detailed; and at least one person must be on hand The boatman knew a small, hazardous inlet on

11 12 WORTH

traversing cliff faces, and here on this scarcely less vertical though lightly vegetated ascent we found their nursery. Numerous babies- green creatures less than a foot long- invited collection, but already they were either fleet or else incredibly know­ ledgeable about crevices inaccessible to our ac­ quisitive [sic] hands. Soldado is topped by a small peak, but below that is a narrow ridge, fairly level- the saddle-where we camped on future occasions. Today it was the chief collecting ground for Richard's banding am­ bitions. Sooty Tern chicks ran about in vmious stages of development and could be caught by hand either as they cowered against the ground, seeking to escape notice, or else if driven into roc­ ky cui-de-sacs. Brown Noddies were still incubat­ ing eggs, so this excursion served to prompt plans for a date on which babies of that species would be FIG. 1. So1dado Rock and Sooty Terns (Sterna equally vulnerable to capture. fuscata), illustrated by Don R. Eckelberry. Sooty Terns are handsome black and white birds with deeply forked tails. Noddies cannot be described as enthusiastically, though their pearly the far side. Here, while his craft bobbed against white caps are indubitably attractive. As we ad­ boulders with each incoming and outflowing wave, vanced up the slope and along the saddle, the air we formed a bucket brigade, he handing things was filled with distracted adults of both species, from tl1e boat to a succession of people progres­ Sooties clamoring constantly in the voice that has sively less submerged until finally all items reposed given them their mariners' nickname of "Wide­ safely above water line. The outboard then found awake," Noddies living up to the less vociferous its voice, and away went our contact with civili­ designation implied in their Latin designation, zation. Tomorrow, if all went well, the boat would Anous stolidus. return. But meanwhile we were as shipwrecked as Wil and I weren't much help to Richard at first. the most celebrated castaways in literature. Having huffed our way to the ridge, we now had to Our first trip was not that dramatic, for we had see where we were. Eastward, the southwestern tip come on only a day's outing. Disembarking was ofTrinidad showed plainly on the horizon, while to just as adventurous, however, as was also the the south one could see palm-fringed shores of the climb up to the "saddle." The slope looked almost Orinoco Delta in Venezuela (though it required bi­ straight up, and it was composed of guano mixed noculars to make out the palms). The latter area with decomposed rock of some sort, the whole sub­ looked completely uninhabited, despite the pres­ strate slipping out from underfoot with each step. ence of primitive Amerindians. A bit to the north­ A few low bushes and plants appeared to offer east, we identified oil rigs in the Gulf ofParia. Thus handholds, but these pulled out when grasped. the Rock commanded a panorama embracing ex­ Besides, we quickly concluded that the vegetation tremes in the stages of civilization, while itself should be spared, for it was the only cover avail­ being so primordial as to antedate them all. able to shelter young birds and, surely, to prevent Next we had to get out our cameras, which total erosion. wasn't much aid to Richard either. How helpful was Nor were fledglings its only beneficiaries. On Tommy being? He, I fear, was the least useful to the our approach to the Rock we observed large iguana whole party. When we brought our eyes back to lizards (not a marine species, as in the Galapagos) the local scene, we found him on his hands and ------

Soldado Rock 13

knees, turning over small rocks one at a time and in relays, over many millenia, so that one need not popping dotlike objects into glass vials. propose even a limited number of avian agents as "Ticks!" he exulted. "Hundreds of them!" Sure the responsible ones. However, Sooty Terns fit the enough, almost every stone covered several tiny, proposition very neatly. They are so-called "tropi­ leggy creatures that could be plucked with fine copolitan" species, with known breeding colonies forceps and transfetTed to collecting bottles. And in all the oceans between the Tropics of Cancer and herein lay the success of our day. I don't know Capricorn. how many terns Richard banded, but those ticks Nevertheless, some arguments could be raised gave us our first inkling of the presence of a bird against that hypothesis. Fairly extensive banding virus on Soldado Rock. studies indicate that these terns come back to the The virus was an annoying one in many ways, same islands where they were born, rather than to but therefore the more cha11enging to scientific foreign ones. Thus if ticks clung to them during investigators. At the lab it behaved erratically, and their absence over the waves, they also would be after several passages in mice we lost it. Meanwhile deposited once more on home ground. But in other workers had found what appeared to be the addition it appears that young Sooty Terns, which same virus in similar ticks from Sooty Tern and are most heavily tick infested, go to sea and remain Brown Noddy colonies in the Dry Tortugas Islands there until they are ready to breed, which may not off Key West. To verify the identity of the two be for several years. Could ticks postpone their viruses, we would have to re-collect it on further own reproduction that long? Tick eggs must be laid tick-seeking expeditions. Also, it now was obvious on the soil and would perish in ocean wastes. that we must look into the possibility of a Scarcely believable but probably true is the relationship between ticks and birds as cycling recent suggestion that fledged Sooty Terns, leav­ agents for the virus: was it solely a tick vims, or did ing their natal island, fl y constantly for three to five it depend also on periodically nesting avian hosts or six years before setting foot again on anything for annual perpetuation? It was childishly simple to that will support their weight. Attesting this mad assume that birds were involved, but a idea are several convincing points. When terns demonstration would be necessary. finish breeding, they do not come back to the is­ Tommy did not consign the ticks indiscrimi­ lands at night to roost; they are not seen again nately to the grinding mortar and pestle-some had until they are prepared for the next nesting cycle. to be saved as pets, which should be rephrased as Sooty Terns are never seen offshore during the "objects of study," in deference to Tommy's quali­ nonbreeding season. They have been observed fications as an unsentimental scientist. He soon only in mid-ocean, far beyond a day's flight from a identified them as Ornithodoros capensis, a name resting place. The number of perches on floating that can indicate at least part of their remarkable jetsam in mid-ocean is far too small to provide interest even to a layman . The genus Ornithodoros roosts for mil1ions of Sooty Terns. And-most con­ includes many medically well-known ticks that vincingly-it has been demonstrated that Sooty transmit diseases such as relapsing fever and Terns are not naturally buoyant. Unlike other gulls typhus to man . But capensis is derived from the and terns, if they are forced to alight on water, their Cape of Good Hope, where this particular species feathers become saturated and they sink. There is was first discovered. TI1e tip of South Africa seems nothing for them to do but keep flying. a long way from Soldado Rock. But tick collectors During several years as constant aeronauts, have found it even farth er afield-indeed, 0. cap­ perhaps some Sooties do out-Magellan Magellan ensis seems to exist on warm islands and seacoasts several times, but there is no evidence that they all around the world. span much more than a quarter of the globe. The That sort of distribution bespeaks transport by wide distribution of Ornithodoros capensis is more birds. If such were the case, what kinds of bird likely to be the result of rare mistakes, occasioned could circle the Equator to spread ticks so far? by such unusual forces as hurricanes, rather than Actually the dissemination might be accomplished regular flights of Sooties or other birds. Perhaps ------

14 WoRm

even driftwood has contributed by transporting So at last we carne again to the point of dis­ derelicts for long distances. Ticks of this genus are embarkation and to the task of lugging everything famous for their ability to survive for long periods up the slope ... tonight was to be crucial. From a without a drop of blood. When I left Trinidad, some virus standpoint, Tommy wanted to catch and of Tommy's early pets were still doing fine in their bleed a large number of adult Noddies, to determine sterile vials. whether they contained antibodies to the new vi­ Noddies were not as suspect, for in their sup­ rus. Richard, too, preferred to study adult birds, posedly stolid way they do come to land to roost at because these gave information about molting night; on some of our visits to Soldado Rock, when sequences that babies could not provide. In ad­ neither species was breeding, we would never­ dition, a banded adult is a better risk for future theless witness a silent influx of Noddies at dusk. recapture, since mortality among fledglings may be TI1erefore it would be difficult for them to span stagge1ing. great jumps of longitude between oceanic islands, Once again I failed to pull my weight, except unless at some seasons they set out on more than that I passed the rum bottle. But when darkness local journeys and then resigned themselves to arrived and everyone else donned head lamps to go continuous flight: once again, we have no evidence creeping along the cliffs to capture dazzled birds, I of such behavior in Noddies. The ways of most sea remained comfortably on my cot, observing the birds remain little known. evening sky. In a way I was as anxious as if I were Obviously we had engaging subjects for end­ on the prowl, too, for the structure of Soldado Rock less study, but we could spare only odd week ends has been weathered by ce11turies of wind, rain and for the game. The first venture impelled us to return salt spray until the exposed stones have a cheesy quickly, because baby Noddies would be ready a texture. 1l1ey look solid, but suddenly a grasped few weeks later. This time we were with a somewhat prominence comes away in your hand or breaks different party that included Tommy, Elisha [Tika­ apart where you have placed your foot. Go tem singh], Tak [Mitsuo Takahashi], the ffrenches and catching with a head lamp in the dark on such one of their energetic lady friends. Adventure al­ cliffs? Not me! ways flanked these trips: now it happened to be a Yet that was the choice of my friends, and I matter of Venezuelan fishermen who had kidnaped shivered for them. Each bird they caught was tied some Trinidadian fishermen a few days previously into a cloth sack, where it would repose until in one of their chronic wars about custody of water tomorrow morning. The team chased Noddies for in the Gulf of Paria. Although Soldado Rock be­ hours, and as people came worn out to their own longs officially to Trinidad, some Venezuelans think cots, I was roused from half sleep into a delightful that the whole of this small country has no right to interim of contemplation. The night could not have be independent of them, and Soldado is certainly been more perfect. Sleeping under the sky is an no more than an offshore jot, only a step from the experience which too few people ever enjoy, and continental mainland. The Trinidadians were those who appreciate 1t indulge themselves too thrown into jail without sanitary facilities. Their rarely. The heavens were magnificent, with many a captors proclaimed: "If anyone wants them back, let constellation 1 could not name. But no smog or the Prime Minister himself come to collect them." reflection from civilization sullied the stars' im­ Consequently we eyed the few boats we saw maculate clarity. Each flame jettisoned itself on the with some excitement, though we were not really eye, as if these were anticipating our own silly apprehensive. The little Spanish we knew would plans to pay them a visit. have been enough to convince antagonistic Ven ­ I don't know what the usual behavior of Brown ezolanos that we were fishing only for birds, the Pelicans may be, but whenever we camped on Sol­ ladies' presence further validating our case. One dado Rock they never went to bed. Round and boat came quite close, but our captain, after first round the island they continued all night long. deviating his course to avoid it, recognized friendly Frigatebirds kept them a remote sort of company. A Trinidadians in the hull. hundred or so of these long-winged fliers persisted ------

So/dado Rock 15

in getting between me and my view of stars and overnight-in some cases as many as several hun­ planets. I assume they were sleeping, for they all dreds from a single captive. This was a real bonus, congregated in the same piece of sky, exactly where for 11ow he did not have to collect them arduously, the prevailing easterly wind cascaded up Sol dado's one by one, from underneath stones. The bags exposed cliff. But it was phenomenal how motion­ were carefully folded, with a notation as to the ex­ less the birds could remain. I would single out one act bird each had held, and later at the lab his tech­ frigatebird that was obscuring a particular star and nicians were assigned the duty of counting them all count the seconds until I could see the same star in their thousands. (The virus again played tricks, again. Sometimes half a minute would elapse until for this huge batch of ticks failed to yield it.) that soaring wraith had deviated far enough in We felt the need to hasten, because the sun somnambulism- is there a more appropriate term? soon beat down in tropical fury. For our own wel­ - to give me a further look. fare it would be good to finish the job, but even Tn such solitude company is a comfortable sen­ more important were the birds, which might suffer sation. The various cots and sleeping bags were heat prostration if not liberated promptly. Thus we clustered close together on the small suitable area finished and broke camp well before noon. Since of the saddle. For the previous two hours, when­ the boatman had not yet appeared, Richard an­ ever I opened my eyes I had seen the winking of nounced that he would go swimming. I was content head lamps as my colleagues climbed perilous cliffs to celebrate the occasion by giving the rum bottle to catch birds. Now that they were asleep, I noticed a final workout. This was Sunday, and Venezuelan that we could claim weak links with the modem pirates being good Roman Catholics, we relaxed in world after all. Far to the west one just made out the our individual ways without perturbation. lights of a Venezuelan village, while to the distant But where was our boatman? A strong wind northeast it was possible to count flares of waste sprang up from the east late in the morning, and we gas burning at the tips of oil rigs surmounting un­ could see the water becoming rougher by the derwater wells in the Gulf of Pari a. Man continued minute. He arrived about two o'clock, having had in his restless, self-advertising ways even here. engine trouble. We wondered what would have Stalking birds with a head lamp is best on a happened if he had been unable to come at all. Our cloudy night and worst under a full moon, for if a conjecture was that when we failed to turn up at the bird can see the stalker behind l1is light it may lab on Monday, Leslie would have called the Coast escape capture. This night had been intermediate, Guard to come and get us. We must agree on some for stars collectively do shed appreciable illumin­ such arrangement for the future. ation, however slight. By working until after ten Loading the boat was a dangerous and ex­ o'clock, the party had managed to snatch all the hausting ordeal, for by this time the waves were so birds they wanted- about 125 of them. Each was high that the captain did not dare bring his craft in placed in a cloth sack, and the sacks were hung all the way. And once we got out into the bay, from a wire under a tarpaulin, to give the bemused away from the lee side of the island, we faced a tenants plenty of air and to protect them in case of procession of rollers coming straight at us. These, ram. combined with the wind, slowed us down so that 1 was awake first in the morning, as might be sometimes we seemed to make no progress what­ expected. Gradually the others carne to. But no hm­ ever. The ride was absolutely endless but far from ried exodus from warm blankets followed. It was too boring, because we had to endure severe torture all delicious to reach out for thermos flasks of hot the way. The bow of the boat would plow into a coffee and then watch the sunrise. Someone finally great wave, rising up until half the craft had over­ spoiled the fun by suggesting work. Reluctantly shot the crest. Then down it would come, bang! everyoue tumbled out, but soon the routine of into the trough, and our respective bottoms banding, bleeding and measuring dispelled mem­ similarly came dowu, band! on the hard wooden ories of fatigue. Tommy discovered that practically seats. Poor old Tak had chosen a forward position every bird had shed ticks galore into the sacks and took the worst beating. We worried not only ------

16 WORTli

about our posteriors but indeed in behalf of our grams. Since blood constitutes roughly ten per cent very lives. More than once, home-made Trinidadian of the mass of most vertebrate bodies, one can con­ boats have broken in two in seas like this. There clude that this particular bird should own five milli­ were no life preservers on board; that was another liters of blood, of which four per cent was being ex­ precaution to be adopted on subsequent trips. tracted every twenty-four hours . In smaller babies But should we try it again? Perhaps we ought the drain would be proportionately greater. That is to scratch Soldado Rock from TRVL's agenda. No! closely equivalent to a human blood donor's giving The virus cycle must be studied on a year-round one pint as regularly as sunrise--which no blood basis. Excursions at three-month intervals should bank would countenance. suffice for that. I missed some of them when away We often saw dead fledglings on the Rock. on other business, but they continued as regularly Ticks might have been responsible for some of the as the calendar. fatalities, though of course we could not tell. I The following year we timed a visit to coincide thought that our babies at the lab should thrive, once more with the presence of Sooty Tern chicks. once the last ectoparasites had left them and rein­ The Rock at night has an utterly different atmo­ festation was precluded. But they immediately pre­ sphere when Sooties are there, for their clamor sented a feeding problem. I was able to buy min­ never ceases. Added to that is the fact that they nows, but they were frozen . Tn New Jersey I had seem to be dominant over Noddies and claim the bought them alive, and the Common Tern fledgling best places for nesting and roosting. At least those apparently recognized them for what they were by sites seemed best to us, because they coincided their activity. Thawed minnows at the lab did not with our preference for the saddle. To be sure, a interest sooties at all, and I was forced to push few Noddies managed to establish themselves here, each one down reluctant throats until an involun­ too, but most of them were concentrated on the tary swallowing reflex was elicited. Even then the lower slopes, where eggs and chicks must have birds often threw up their meals after Thad replaced more likely chances for dislodgment. them in the cage. Tommy decided to take four Sooty babies back The recalcitrant captives were nevertheless in­ to the lab for vims inoculation tests, after I assured structive during their few weeks of survival. Owing him that I once successfully reared an injured to cramped conditions at the lab, T was able to give young Common Tern in New Jersey. All Thad had them only two square feet of floor space. Yet in a to do then was buy bait minnows, which the fledg­ couple of days the birds had positioned themselves ling had gulped in enormous quantities. At the lab in definite territories within that small area. I soon in Port-of-Spain we gave the birds a small cage, learned to recognize them individually by minor situated over an enameled pan filled with water to differences in size, markings and behavior. Thus, trap any ticks that might fall from them. Any ticks! when I came to feed them, I would find each one Each young Sooty Tern dropped almost a thou­ situated in a spot that it had adopted for itself, sand during the next five days. probably not without initial bickering but at last This phenomenon set me off on some calcula­ with communal consent. tions that might indicate what the life of a young Undoubtedly they had responded to one of tern on Sol dado Rock must be like. If one bird is va­ the instincts that promotes survival of fledglings in cated by an average of two hundred ticks per day, sea-bird colonies. Retuming parents, arriving with it probably becomes host to two hundred new ones food, somehow recognize their own young and will during the same period. Thus it is constantly para­ not feed babies indiscriminately. Bnt the respon­ sitized by a population of 011e thonsand gold dig­ sibility-or liability-resides in both camps: chicks gers. These blood-sucking arthropods may each re­ also must remain at home where they can be re­ move only one thousandth of a milliliter of blood cognized. This seems nonsensical to me, for the apiece during their sojourn, but the result of their flock ought to prosper just as well if everybody fed concerted feeding must lead to a loss of one fifth of anyone's children regardless of parentage, but that a milliliter daily. The largest baby weighed barely 50 is not how things work in nature. No doubt our de- So/dado Rock 17 partures from Sol dado, after we had mucked every­ waterproof, and so it was. It refused to allow water thing up with our chasing and herding practices, to drain through its closely woven fabric, and soon were marked by hundreds of individual treks as I was lying in a miniature swimming pool. babies returned to their precisely ordained domains At approximately the same moment that I de­ of pebbles. cided something must be done and popped my That trip gave us the virus once more-from head out from under the soggy blanket, other birds rather than ticks, this time. Now we could heads popped out, too. "Wide awake!" shouted revisit the Rock with reduced feelings of pro­ Elisha. One by one we upended cots to empty them fessional urgency. However other underlying urges and wrung out blankets, though that was a useless or repulsions remained, especially fear. The next reflex action. quarterly trip was cancelled by a storm warning, but What can you do under such circumstances we felt safe enough a week later. On that very except dwell on your misery? Tommy, bless him, morning another storm brewed, but we decided to knew the precise answer. "Let's play word games," go anyhow, for TRVL' s calendar said we must. This he suggested. "First we'll play 'Rivers, Cities and Saturday we were Tommy, Richard, Elisha, and Countries.' 1'11 begin: O.K., 'Afghanistan.' Your Charlie Collins, a graduate student from the Univer­ tum, Richard-your Jetter is 'N.' " sity of Florida, currently making ornithological So it rained and so we played through the studies at Simla in the Arima Valley. (I shall have night. Five o'clock brought a slight remission in more to report about Charlie.) the deluge, by which time Elisha was no longer re­ At Cedros, wl1ile we were loading the boat, a sponding to calls for his next tum. He was slumped kindly policeman informed us that the radio was against a tiny outcrop of rock that sheltered an in­ broadcasting hourly warnings from tl1e Coast cubating noddy at his elbow. The rest of us had Guard and Weather Bureau, advising all small craft run out of names but had begun to fabricate them to remain ashore. He had no authority to prevent for the sake of endurance. "Don't you suppose our embarkation, so we put it up to the boatman. In there may be a place somewhere called Dart­ his opinion the storm had already passed, for the mouthsdorp?" asked Charlie. water had been much rougher earlier, and someone Winds diminished, clouds blew away, and the had merely neglected to te11 the radio people to sun came up in splendor. Like drenched vultures, discontinue their automatic tape recording. The sea we spread ourselves to its rays, and like them we was smooth, and we had a serene ride to Soldado. soon found capable wings for our work. But as we As usual, l went to bed early and the others left Soldado that time, 1 resolved to consign the followed after their labors were finished. Then the project to younger hands. Charlie, for example, was first large drop splashed on my face. Frigatebirds inspired as l might have been one generation had been sleeping overhead, and I suspected that previously. Finding a partia1Iy mummified frigate­ this might not be rain. However when l opened my bird carcass, he insisted on b1inging it back as a eyes 1 found that the stars had been obscured and valuable trophy, smell and all. "It will make a it was so dark that it was impossible to know splendid skeleton," he protested over our protests. whether frigatebirds were still up there or not. An­ That indeed was my last trip, but only in part other drop, and auotl1er. "A passing shower," I because of faint heart. Vints studies had now thought, and pulled the blanket over my head. reached a reasonably satisfactory stage, and TRVL Now the rair: pelted down. Soon the blanket policy decreed that further i1westigations could be was saturated. Well, l had slept out in rain before, made less routinely, if at all. [The chapter ends with and in the tropics body heat often serves to make brief comments about searching for ticks and even a wet shroud uot too uninhabitable. But 1 had virsuses among seabirds on the Morant Cays of forgotten to reckon with the canvas cot. This ad­ Jamaica.] mirable article of field equipment is designed to be Pp. !8-22 in Studies in Trinidad and Tobago Omithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. II, 2002.

NATAL PTERYLOSIS OF TWO TRINIDADIAN OVENBIRDS (FURNARIIDAE)

CHARLES T. COLLINS AND TAMARA A. ARAYA Department ofBiological Sciences, California State University, Long Beach, CA 90840, USA

ABSTRACT.-Tl1e number and distribution of natal downs is reported for two Trinidadia11 ovenbirds (Fumariidae): the Gray-throated Leaftosser (Sclerurus albi­ gularis) and the Yellow-chinned Spinetail (Certhiaxis cinnamomea). The total number of neossoptiles present is greater than reported for other fumariid species and more typical of totals repmted for open-cup nesting species.

REsuMEN.-Se registra la cantidad y distribuci6n de plumas natales para dos especies de homeros (Fumariidae) de Trinidad: el Raspa Hoja Gargantigrfs (Sclerurus albigularis) y el Gliitio de Agua ( Certhiaxis cinnamomea). La cantidad total de neo­ soptilos presentes es mayor que Ia registrada para otras especies de fumariidos yes mas tipica de Ia registrada para otras especies de nidos abiertos.

KEY WORDS.-Certhiaxis cinnamomea, Furnariidae, Gray-throated Leaftosser, natal pterylosis, Sclerurus albigularis, Trinidad, Yellow-chinned Spinetail

The ovenbirds (Fumariidae) are a large and end of a burrow (Skutch 1967, 1969, Vaurie 1980, diverse family of suboscine passerine birds Ridgely and Tudor 1994, Zyskowski and Prum inhabiting Central and South America. The family 1999). The avifauna of Trinidad and Tobago in­ includes 231 species in 53 genera of mostly dull cludes only five species of fumariids in the genera brown, mfous or grey plumaged birds and reaches Synallaxis (two species), Certhiaxis, Xenops and its greatest diversity in the Andes and soutll­ Sclerurus (ffrench 1991 ). central South America (Vaurie 1980, Sibley and Despite the family's exceptional geographic Monroe 1990, Ridgely and Tudor 1994). An ad­ range and ecological diversity, only a few of its ditional 49 specJes in 13 genera of woodcreepers species have been studied in depth (Skutch 1952, (Dendrocolaptidae) have frequently been i11cluded 1969) and details of their life history and plumages in an expanded Fumariidae (Feduccia 1973, Sibley are lacking for many species. One aspect of the and Ahlquist 1990). biology of the Furnariidae that has been given Fumariids, known by such evocative names as minimal attention is the number and pattern of natal foliage-gleaners, treehunters, spinetails, cinclodes downs (neossoptiles) on the newly hatched altricial and leaftossers, have "radiated into nearly every young. Although Skutch (1969) generalised that all conceivable niche and habitat from lowland and fumariids have "sparse dovm typical of pas­ montane forests ... to grasslands, marshes and even setines," the only detailed study (Collins et al. rocky areas and meadows near the level of per­ 1991) examined single specimens of Spotted manent snow in the Andes" (Ridgely and Tudor Barbtail (Premnoplex brunnescens), Streak-capped 1994:23). Their nests are equally diverse, including Treerunner (Thripadectes virgaticeps), and White­ enclosed mud nests, bulky stick nests, and incon­ whiskered Spinetail (Synallaxis candei). This spicuous nests in holes in trees and walls or at the paper, part of a continuing analysis of the natal

18 Natal Pterylosis in Ovenbirds 19

TABLE 1. Number of neossoptiles and nest type of fumariid passerines.

Total number Species of neossoptiles Nest type• Sclerurus albigularis 339-354 burrow Certhiaxis cinnamomea 172-223 bulky stick Synallaxis candei 131 b bulky stick Thripadectes virgaticeps 123b burrow Premnoplex brunnescens 121 b domed, mossy "from Skutch (1967, 1969) and Bosque and Lentine (1987) bfrom Collins etal. (1991)

pterylosis ofNeotropical passerines (Collins, 1973, have fewer neossoptiles than open-cup nesting 1982, 1990,CollinsandMcDaniel 1989,Collinsand species. The more normal trend has previously Araya 1998), presents data on two Trinidadian been noted in Neotropical tyrant flycatchers (Ty­ fumariids: the Ye1low-chinned Spinetail (Certhiaxis rannidae; Collins and McDaniel 1989) and was cinnamomea) and Gray-throated Leaftosser (Scle­ suggested by the low totals for the three other rurus albigularis). fumariids examined to date (Collins et al. 1991). In the case of S albigularis, the number of dorsal METIIODS neossoptiles in the scapular, femoral tracts and the mid-dorsal region of the spinal tract would seem Two specimens (Stage A; see Wetherbee 1957) more appropriate for an open-cup nesting species of S. albigularis were collected (CTC #I 52) from a where cryptic colouration could be important. This burrow nest in a bank of an upper montane rain suggests that the use of burrows for nesting is of forest trail leading to El Tucuche on 27 June 1963. rather recent origin in Sclerurus, but burrows Seven specimens of C. cinnamomea were collected appear to be the typical nest site for other members (CTC #371, #372) from two stick nests in low of the genus (Skutch 1969). mangroves at the edge of Caroni Swamp near When there is an adequate sample, as in Cacandee Village on 12 September I 964. All spec­ Certhiaxis, a single pattem and number of neos­ imens were examined under a binocular dissecting soptiles can be chosen to characterise a species. A microscope and the number and distribution of 'typical' number can be calculated. This is the total neossopti les recorded. The tenninology for neos­ of the number of neossoptiles most frequently soptile tracts and regions within tracts follows observed in each tract or region (Collins 1973). By Wetherbee (1957), Collins and Bender (1977) and this method tl1e typical number for this species is Collins and Araya (1998). 192 neossoptiles (Table 2). When intraspecific vmiation is great, as in this case, it is l1ard to RESULTS AND DISCUSSION determine a typical number and it is preferable to utilise the average number (rounded to the nearest Both species had a dense covering of whole number) of neossoptiles present in each tract neossoptiles ranging from 339-354 in 18 tracts or or region and assign it (bilaterally) to that tract or regions in S. albigularis to 179-223 in 17 tracts or region (Minsky and Collins 1983). The sum of the regions in C. cinnamomea (Table 1). This is sub­ average numbers for all tracts and regions of stantially more neossoptiles in more tracts and neossoptiles for C. cinnamomea is 195 (Fig. 1), the regions than the 121-131 found in other furnariids same as the mode of the individual specimen totals (Table l;Collinsetal.1991). Thehigbernumbersin and only slightly more than the average total of 193 Sclerurus and Certhiaxis do not follow the general neossoptiles (Table 2). trend which is for closed-nest building species to There were several interspecific differences 20 COLLINS AND ARAYA

TABLE 2. Distribution ofneossoptiles in Sclerurus albigularis and Certhiaxis cinnamomea (Fumariidae).

Sclerurus Certhiaxis cinnamomea Tract (region) albigularis Nest # ! Nest #2

Capital Coronal 8/8. 9/8 919 8/9 9/8 11/8 13110 9/8 919 Ocular 4/4 4/2 3/3 4/4 7/5 3/3 3/2 4/5 2/3 Occipital 4/4 5/5 4/5 4/3 3/3 4/4 6/6 3/3 4/4 Spinal Spinalb 7 9 Mid-dorsal 21121 26/34 8/10 9/8 9/8 819 12113 10/10 9/7 Pelvic 21118 12111 4/4 312 212 4/1 4/3 110 Oil Medial pelvicb 5 7 0 0 3 0 0 3 7 Scapular 23/23 24/22 8/8 6/6 919 7/8 6/6 9/8 7/7 Femoral 24/22 25/28 10111 12110 9111 8/8 8/9 819 8/8 Ventral 14/12 16/ 13 1117 617 12/8 5/6 7/4 4/4 8/8 Crural 7/6 617 lOll! 13/8 10/10 9/9 7/6 9/10 10 /l 0 Caudal Rectrices 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 Rectrix coverts 3/3 4/3 Alar Primaries 10/7 10/10 10/9 8/8 10/10 9/9 8/8 10/9 8/9 Primary coverts 6/6 2/J 1/2 1/0 7/8 1/0 110 5/3 5/5 Secondaries 7/8 5/6 7/7 0/7 7/4 717 8/7 Greater secondary coverts 11/9 10/9 8/8 8/7 919 8/9 8/8 9/10 919 Middle secondary coverts 8/7 8/8 210 2/0 3/4 0/0 010 3/3 111 Ca!Eel remex 0/1 1/1 010 010 1/0 010 Oil 0/0 010 Total 339 354 202 179 223 172 182 195 195 "number ofneossoptiles on right/left side bunpaired tracts on midline; an others paired. noted in the pattem of neossoptiles of these two neossoptiles have so far been reported only from species. Carpal remex neossoptiles were present in Neotropical tanagers (Collins and Araya 1998). both specimens of S. albigularis but were found in l11e distribution of neossoptiles in the ocular only two of seven specimens of C. cinnamomea region was confined to the extreme posterior end of (Table 2) . Neossoptiles on the secondaries were one row and gave the appearance of belonging to numerous in an specimens of Certhiaxis but absent a possibly unique short row of downs almost in Sclerurus. Neossoptiles were present in unpaired perpendicular to the posterior end of tl1e coronal rows in the spinal and medial pelvic regions of the row. This unique pattern was noted in the other spinal tract in Sclerurus, but in Certhiaxis medial fumariids examined to date (Collins eta!. 1991) and pelvic neossoptiles were only present in three of may be characteristic of the family. However, as seven specimens; spinal region neossoptiles were noted earlier (Collins !990), the scarc1ty of absent in Certhiaxis (Table 2). Medial pelvic specimens, particularly of fumariids, greatly limits neossoptiles have previously been reported from more detailed interspecific or intraspecific com­ several temperate zone oscines (Collins and Bender parisons as wen as correlations with aspects of 1977, Minsky and Colhns 1983) while spinal region nesting ecology ofNeotropical passerines. Natal Pterylosis in Ovenbirds 21

. :. . \ :.

Dorsal Ventral

FIG. I. Natal pterylosis of Certhiaxis cinnamomea. Each dot represents a single neossoptile. Pattem sho\VTl is the average number ofneossoptiles in each tract and region.

ACKNOWLEDGEMENTS Club 102:37-39. COLLINS, C. T. 1990. Intraspecific variation in the Support for field work in Trinidad was received natal pterylosis of the Ochre-bellied Flycatcher from the Frank M. Chapman Fund of the American (Tyrannidae). Bull. Brit. Omithol. Club 110:143- Museum of Natural History, New York. Collection 145. of these specimens was authorised by a Special COLLINS, C. T.,AND T. A. ARAYA. 1998. Natal Game Licence issued by the Trinidad and Tobago pterylosis of tanagers II: Tachyphonus, Ram­ Forest Department. We are grateful to K. E. Bender phocelus and Tangara. Bull. Brit. Omithol. for her preliminary analysis of these specimens and Club 118:172-178. toM. Lentino and T. Manolis for helpful comments COLLINS, C. T., AND K. E. BENDER. 1977. Natal on the manuscript. This paper is dedicated to Rich­ pterylosis of the House Finch. Bull. So. Calif.. ard ffrench, friend, colleague and cheerful field Acad. Sci. 76:209-211. compamon. COLLINS, C. T., M. MAR1"1 A., AND M. LENTINO R. 1991. Natal pterylosis of Premnoplex brun­ LITERATURE CITED nescens, Thripadectes virgaticeps, and Synal­ laxis candei (Fumariidae). Bull. Brit. Om­ BOSQUE, C., AND M. LENTJNO. 1987. TI1e nest, eggs ithol. Club 111:118-120. and young of the White-whiskered Spinetail, COLLINS, C. T., AND K. M. MCDANIEL. 1989. TI1e Synallaxis (=Poecilurus) candei (Aves: Fur­ natal pterylosis of closed-nest building tyrant nariidae). Wilson Bull. 99:104-106. flycatchers (Aves: Tyrannidae). Bu1l. So. Calif. COLLINS, C. T. 1973. The natal pterylosis of the Acad. Sci. 88:122-130. Swa11ow-Tanager. Bull. Brit. Omithol. Club FEDUCCIA, J. A. 1973. Evolutionary trends in the 93:155-157. Neotropical ovenbirds and woodhewers. Omi­ COLLINS, C. T. 1982. The natal pterylosis of Ma­ thol. Monogr. 13:1-69. nacus manacus (Pipridae). Bull. Brit. Omithol. FFRENCII, R. 1991. A guide to the birds ofTrinidad 22 COLLINS AND ARAYA

and Tobago. 2nd ed. Cornell University Press, SKUTCH, A. F. 1967. Life histories of Central Ithaca, New York. 426 pp. American highland birds. Pub!. Nuttall Orni­ MINSKY, D., AND C. T. COLLINS. 1983. Natal thol. Club 7:1-213. pterylosis of Amphispiza sparrows. Condor SKUTCH, A . F. 1969. Life histories of Central 5:375-376. American birds. III. Pac. Coast Avifauna 35:1- RIDGELY, R. S., AND G. TuDOR. 1994. The birds of 580. South America. Vol. II. The suboscine pas­ V Al.JRIE, C. 1980. Taxonomy and geographical serines. University of Texas Press, Austin, distribution of the Fumariidae (Aves, Pas­ Texas. serifonnes). Bull. Amer. Mus. Nat. Hist. 166:1- SIBLEY, C. G., AND J. E. AHLQlJIST. 1990. Phylogeny 357. and classification ofbirds: a study in molecular WETHERBEE, D. K. 1957. Natal plumages and evolution. Yale University Press, New Haven, downy pteryloses of passerine birds of North Connecticut. 976 pp. America. Bull. Amer. Mus. Nat. Hist. 113:339- SIBLEY, C. G., AND B. L. MONROE, JR. 1990. 436. Distribution and taxonomy of birds of the ZYSKOWSKI, K., AND R. 0. PROM. 1999. Phylo­ World. Yale University Press, New Haven, genetic analysis of the nest architecture of Connecticut. 1111 pp. Neotropical ovenbirds (Fumariidae). Auk SKUTCH, A. F. 1952. Life history of the Chestnut­ 116:891-911. tailed Automolus. Condor 54:93- 100. Pp. 23-36 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. II, 2002.

SABRE RATTLING AT THE LEK: MORPHOLOGICAL VARIATION AND ITS SIGNIFICANCE IN THE WHITE-TAILED SABREWING ( CAMPYLOPTERUS ENSIPENNIS)

FLOYD E. HAYES Department ofBiology , Caribbean Union College, P. 0. Box 175, Port of Spain, Trinidad and Tobago and Department ofLife Sciences, University ofth e West Indies, St. Augustine, Trinidad and Tobago

ABSTRACT.- The White-tailed Sa brewing ( Campylopterus ensipennis) occurs in three disjunct populations: (1) the Cordi11era de Caripe and (2) Peninsula de Pari a of Venezuela; and (3) the island of Tobago, where a population bottleneck occurred after a hurricane in 1963. The three populations are chromatically indistinguishable, but bill length was greatest in the Peninsula de Paria and tail length shortest in the Cordillera de Caripe. The sexes are chromatically dimorphic, with wing length, tail length and body mass greatest for males. Bill length is shorter for males, which typically hawk for arthropods whereas females typically glea11 arthropods from foliage. Breeding occurs during January-April, and moult during March-July. 1l1e proportion of immatures on post-hmicm1e Tobago during 1996-200 I was significantly higher than in all pre-hurricane populations combined, suggesting m1 increasing population. Adult male Campylopterus hummingbirds possess a widened and sharply bent rachis or 'sabre' in the outermost primary feathers, which appears related to sexual selection. Lek polygyny is widespread in the genus. I evaluate three hypotheses of sabre function: (l) wide sabres confer an advantage during male-male conflicts (sabre-rattling hypothesis); (2) females prefer to mate with wide sabred males (sabre-flashing hypothesis); and (3) wide sabres may enhance aerial foraging on arthropods (sabre-sickle hypothesis). However, the evidence supporting each hypothesis is meagre.

R..ESUMEN .-EI Ala de Sable de Cola Blanca ( Campylopterus ensipennis) se distribu­ ye en tres poblaciones disyuntas: (1) la Cordillera de Caripe y (2) Ia Peninsula de Paria de Venezuela; y (3) Ia isla de Tobago, en donde Ia poblaci6n paso por un cuello de botella despues del hurican de 1963. Nose pueden distinguir las tres poblaciones croma­ ticamente, pero Ia longitud del pi co fue mayor en Ia Peninsula de Pari a y Ia longitud de Ia cola fue menor en la Cordillera de Caripe. Los sexos son dim6rficos cromaticamente, y los machos presentan una mayor longitud de ala, cola y masa del cuerpo. La longitud del pico es mas c01ta en los machos quienes tfpicamente cazan artr6podos en vuelo mientras las hembras tipicamente los recogen en el follaje. La nidificaci6n ocurre entre enero-abril, y Ia muda entre marzo-julio. En el periodo post-huracan en Tobago durante 1996-200 I Ia proporci6u de inmaduros fue significativa-mente mayor que en todas las poblaciones pre-hurican, esto sugiere que Ia poblaci6u esta aumentando. Los machos adultos de los colibries Campylopterus tienen un raquis o 'sable' ensanchado y bien doblado en las primarias mas extemas, que parecen estar relacionados con Ia selecci6n sexual. La arena polyginica es comun en el genera. Se analizan tres hip6tesis de la

23 24 HAYES

fun cion del sable: (1) los sables anchos dan una ventaja durante los conflictos macho­ macho (hip6tesis de sable cascabel); (2) las hembras prefieren juntarse con machos con sables anchas (hipotesis de despliege del ala de sable); y (3) los sables anchos pueden mejorar el forajeo sabre artropodos (hip6tesis del ala de sable en fmma de hoz). Sin embargo, hay poca evidencia para soportar cada hip6tesis.

KEY WoriDS.-Campylopterus ensipennis, demography, geographic variation, hummingbirds, lekpolygyny, morphology, moult, sexual dimorphism, Tobago, Trochili­ dae, Venezuela, White-tailed Sabrewing

Sabrewing hummingbirds of the genus Campy­ captured individuals at Tobago. By comparing the lopterus, which literally means 'curve-winged' age structure of the post-hurricane Tobago popu­ (Johnsgard 1997), are characterised by a widened lation with pre-hurricane specimens from Tobago and sharply bent racl1is or shaft (herein refeJTed to and from the mainland as well, I attempt to assess as 'sabre') in the oute1most primary featl1ers of whether the current Tobago population is increas­ adult males (e.g., illustrations in Ridgeway 1892, ing or is stable. I further postulate several hypoth­ Behnke-Pedersen 1972, Sick 1993; see Fig. 1). This eses for the function of the sabre-shaped primaries distinctive trait is also shared by the Scaly-breasted of the White-tailed Sabrewing and other sabre­ Hummingbird (Phaeochroa cuvierii) and the Swal­ wings ofthe genus Campylopterus. low-tailed Hummingbird (Eupetomena macroura), which presumably are closely related to Campy­ METHODS lopterus (e.g., Sibley and Monroe 1990) and were recently merged into Campylopterus by Schuch­ I examined and measured 75 specimens of the ann (1999). However, the function of the sabres and White-tailed Sabrewing in the AMNH, FMNH and other aspects of sabrewing biology remain poorly USNM; measurements of an additional 166 speci­ understood. mens were provided by colleagues in the BMNH, The White-tailed Sabrewing (C. ensipennis) is COP and LACM (see Appendix for museum acro­ regarded as a monotypic species whose distJibu­ nyms and localities of specimens). For each speci­ tion is limited to three disjunct populations: (1) the men the sex, locality and date were recorded from Cordillera de Caripe and (2) Peninsula de Pmia, both the attached specimen labels. The coordinates of in northeastern Venezuela, and (3) the island of each Venezuelan locality were obtained from Payn­ Tobago (Collar et al. 1992). Because of its limited ter (1982) to dete1mine which population it be­ distJibution and dwindling montane forest habitat, longed to. Using vernier calipers, the following size it was regarded by Collar eta!. (1992) as a globally variables were measured (nearest mm): bill length threatened species. In Venezuela, the White-tailed (BL), from feathered base to tip of maxilla; wing Sabrewing is threatened by widespread deforest­ chord length (WL), from bend of folded wing to tip ation. On Tobago, it was considered to be a com­ of longest primary feather; tail length (TL), from mon resident until Hurricane Flora destroyed nearly base of tail to tip of longest rectrix; and 'sabre' all of the island's forest in 1963; afterward the width (SW), from the widest part of the rachis of Tobago population was regarded as extirpated until the outermost (tenth) primary (nearest 0.5 mm). itsrediscoveryin 1974(ffrench 1975, 1991).Since Tarsus length of museum specimens was not meas­ then its population has gradually increased (Hayes ured because of their fragile condition. eta!. 1995, 1997a, in prep). I examined the feathers of each specimen, par­ In this paper I examine geographical variation, palticularly on the wings and tail, for evidence of sexual dimorphism, moult, and population age moult l examined the lateral surfaces of the bill of structure of the White-tailed Sabrewing based on each specimen for cOJTUgations, which is charac­ museum specimens throughout its range, and on teristic of immature hummingbirds (Ortiz-Crespo Morphological Variation in the White-tailed Sabrewing 25

statistic) or Mann-Whitney U test (U or z statistic). Sexual dimorphism in each morphological variable was tested for each population with a Student's t test or Mann-Whitney U test. Differences among the three populations were tested for each morpho­ logical variable using a one-way analysis of vari­ ance (F statistic) or a Kruskal-Wallis test (H sta­ FIG. I. Sketch of flight feathers of adult male tistic); when significant differences were found, an Campylopterus hummingbirds, illustrating widened a posteriori Bonferonni 's test was used for pairwise rachis of outennost primaries (sabres). Adapted contrasts. Morphological differences between the from Sick ( 1993 ). specimens (pre-hurricane) and live birds (post-hur­ ricane) from Tobago were tested using a Student's t test or Mann-Whitney U test. In the above analy­ 1972), to dete1mine the proportion of immature and ses, the parametric tests (Student's t test and one­ adult birds in a population, and to test the hypo­ way analysis of variance) were used only if the data thesis that widened sabres are a secondary sex sets were normally distributed and variances were character of adult males. l also compared bi11length homogeneous. Chi-square tests ('"/! statistic) were of immatures and adults to test the hypothesis that used to test for differences in the proportions of bi II length is shorter in immatures. adults and immatures using two methods of ageing, I also examined and measured 83 individuals of and for differences in the proportions of adults and the White-tailed Sabrewing which I captured, band­ immatures between the historical (pre-hurricane) ed and released (one died) at Tobago from June and recent (post-hurricane) populations. All statis­ 1996 to August 200 I. In addition to the above ical tests and their assumptions are described by measurements, I measured (nearest mm): tarsus Chew (1977) and Zar (1984). length (TS), from the junction of tibiotarsus and tarsometatarsus to the distal junction of the toes RESULTS and tarsometatarsus; and body mass (BM), with a 50 g Avinet spring scale (nearest 0.1 g). No mass Measurement variation.-Wing length and tail data were available on the museum specimens. I length measurements by colleagues average sig­ also examined each live individual for moult and, in nificantly larger than mine for males in both Venez­ a smaller subset of individuals, bill corrugations. uelan populations (P < 0.05), but not in the Toba­ The data were discarded for 15 old trade spec­ go population or for females in any population. No imens either lacking locality data or labelled as such differences occur in measurements of bill 'Bahia', 'Trinidad', 'West Indies' (C. ensipennis length for any sex in any population. Because no has not been reliably recorded at these localities) or differences occur for females and the differences 'Venezuela' (see Appendix). The data were also dis­ for males appear attributable to a greater propor­ carded for a recently fledged specimen and for tion of adults in the samples measured by col­ three specimens with an obvious error in measure­ leagues, the measurements are combined for sub­ ment or sex detennination. For specimens with bro­ sequent analyses. ken bills, moulting tenth primaries or moulting cen­ Geographic variation.-There are no discern­ tral rectrices, the datum for each affected variable able differences in the colouration or pattern of was discarded. For the purposes of analysis, the plumage among the three populations. Based on localities were pooled into three disjunct popula­ measurements of museum specimens, bill length is tions: (I) the Cordillera de Caripe, (2) the Peninsula significantly longer for both sexes from the Penin­ de Paria and (3) Tobago. ula de Paria population and tail length is signif­ Differences between my measurements and icantly shorter for the Cordillera de Caripe popu­ those of collaborators were tested for each sex lation (Table I). No other morphological measure­ within each population with a Student's t test (t ment differ significantly among the populations, 26 HAYES

TABLE 1. Descriptive measures of size variables for three White-tailed Sabre wing populations (based on museum specimens), with statistical comparisons between the sexes and among populations. BL = bill length; WL = wing length; TL = tail length; SW =sabre width (see Methods for definitions).

Cordillera de Caripe Peninsula de Paria Tobago Variable x(SD)range(n) x(SD)ranBe(n) x(SD)range(n) Significance

BL d' 24 .6(0.96)23-27(40) 25.8(0.98)24-27(19) 25.0(0.97)23-26(21) F=l 0.6, P

TABLE 2. Descriptive measures of size variables for pre-hurricane (based on museum specimens) and post­ hunicane (based on live birds) populations of the White-tailed Sabrewing on Tobago, with statistical comparisons between the sexes and populations. BL = billlengtl1; WL =wing length; TL =tail length; TS = tarsus length; SW =sabre width; BM =body mass (see Methods for definitions).

Toba~o (~re-hurricane) Toba~o (j:!ost-hurricane) Variable x(SD)range~n) x~SD2 range{n2 Significance BL d' 25.0(0.97)23-26(21) 25.0(0.69)23-27(43) t = 0.20, p = 0.84 'i' 27.7(1.16)26-30(12)b 27.7(0.89)26-30C3W t = 0.00, p = 1.00 WL d' 76.3(3. I I )69-83(19) 77.0(2.55)71-82(35) t = 0.96, p = 0.34 'f 72.7(2.37)68-75(11)" 71.9(2.18)68-76(37)b t = 0.99, p = 0.33 TL rf 51 .0(1.80)48-54(21) 53.0(3 .00)45-58(44) z = 3.34, P = 0.002 'i' 48.8(1.94)44-51 (11 )" 50.0(3 .02)41-54(36)b z = 1.09, p = 0.28 TS d' 6.0(0.44)5-7(43) 'i' 5.9(0.48)5-7(34) sw d' 2.45{0.74) 1.50-3.35(20) 2.3 I (0.64)1.70-3.45(37) z = 0.15, P= 0.88 'i' 1.28(0.22)1.00-1.75(1 1)b 1.36(0.22)1.05-1.90(36)b z = 1.06, p = 0.29 BM rf 10.6(0.51 )9.0-12.2(37) !i? 8.4(0.4 7)7.6-9 .4(36)b "differs from males of same population, P < 0.01 bdiffers from males of same population, P < 0.00 I M01phological Variation in the White-tailed Sabrewing 27

TABLE 3. Seasonal occurrence of moult in the Moult.-Based on exami11ation of specimens and White-tailed Sabrewing for specimens (all popula- live birds, moult occurred between the months of tions combined) and live birds (Tobago only; data March and July, with a peak during May (Table 3). include recaptured individuals). No data were available for the months of Septem­ ber-October. Although no detailed analyses were SJ2ecimens L1ve (Toba!l;O~ made of the moult sequence for individual feathers, Month None Moult{%} None Moult{%) a few patterns were evident. The rectrices moulted Jan 5 0 (0.0) simultaneously with the outer primaries in four Feb 14 0 (0.0) cases and with the inner primaries in one case; in 12 Mar 6 0 (0.0) 11 1 (8.3) cases the primaries and rectrices did not appear to Apr 0 (0.0) be moulting simultaneously (Table 4). Based on the May 13 9(40.9) appearance of fresh (recently moulted) inner rectli­ Jun 4 1 (20.0) 33 8 (19.5) ces and moulting outer rectrices, the inner rectrices Jul 2 I (33.3) 24 0 (0.0) apparently moulted first (Table 4). Aug 8 0 (0.0) The rectrices of a female captured in Tobago on Sep 24 June 1996 were unintentionally removed. When Oct recaptured on 24 March I 997, the rectrices had Nov 2 0 (0.0) been replaced. A female missing a claw on the right Dec 0 (0.0) 10 0 (0.0) hind toe and possessing an abnormally long claw on a left fore toe had heavily worn plumage on 30 June 1999, suggesting that it had not moulted; but wing length of females differs nearly signifi­ when recaptured on 8 August 2001, its plumage cantly (P = 0.057) among the three populations, was fresh, indicating recent moult, although two with Cordillera de Caripe birds having the shortest additional claws were missing on the left fore toes. wings (Table 1). However, bivariate plots and prin­ Population age structure.-Relatively few spec­ cipal components analysis demonstrate consider­ imens (17.8%) exhibited comtgations on the bill able overlap among the populations. (Table 5). These specimens, which were diagnos­ The measurements of the specimens (pre-hur­ able as immatures, were obtained between 10 Feb­ ricane) and live birds (post-hurricane) from Tobago ruary and 6 August. The bill length of immature did not differ in bill length, wing length or sabre specimens with corrugations on the bill (x= 24.7 width; however, tail length averaged significantly mm,SD= I.OO,n = 9ford"d"; x=27.4 mm,SD= 1.13, longer (3 .8%) for live males but not for live females n = 7 for ~ ~) averaged slightly less than that of (2.4%; Table 2). adults for both sexes (x=25.0mm, SD = 0.84, n = 41 Sexual dimorphism.-White-tailed Sabrewings for a" a"; x = 28.2 mm, SD = 1.06, n = 31 for~~), but are sexually dimorphic in both plumage and mor­ in both cases the differences were not significant (t phometries. Females possess a white !oral streak, = 1.05, df=48, P= 0.30 for d'd'; t= 1.15, df= 36, P= which is absent in the males, and the underparts of 0.08 for 1111). females are suffused with grey in contrast with the More than a third (36.9%) of male specimens unifmm green underpmis of males. Based on wing from all localities combined and two-thirds of live length, tail length and body mass, males are sig­ males from Tobago had sabre widths < 2.3 mm nificantly larger than females; l1owever, females (Table 5). Only a third of 27 male sabrewings with have significantly longer bills (Tables 1-2). Tarsus sabre widths < 2.3 mm exhibited corrugations on length does not differ between the sexes (Table 2). the bill; in contrast, none of 21 males with sabre Sabre width is significantly wider and more variable widths > 2.3 mm exhibited corrugations on the bill for males (Tables 1-2); furthermore, the sabre width (x} = 6.57, df = I, P = 0.01). Direct evidence that of males has a non-overlapping bimodal distribu­ sabre width increases with age was provided by tion, ranging from 1.50-2.20 mm (u = 53) and from recaptures of iliree banded males at Tobago: the 2.50-3.55 mm (n = 66). first with sabre width of 1.8 mm on 7 July and 31 28 HAYES

TABLE 4. Chronological sequence of moult in the W11ite-tailed Sabrewing.

Date (m-d-y) Sex Population Feathers moulting Source" 03-24-1997 d' Tobago primary 9; recttices Hayes unpubl. data 05-03-1892 d' Tobago primaries 9 (last) and I 0 FMNH42535 05-07-1892 d' Tobago outer rectrices (inner fresh); FMNH42537 primary 9 last to molt on right wing 05-09-1903 d' Tobago primaries 9 and 10 AMNH479326 05-13-1903 d' Tobago outer primaries (rectrices wom) AMNH479331 05-14-1903 d' Tobago inner rectrices AMNH479328 05-14-1903 ~ Tobago inner primaries, rectrices AMNH479333 05-21-1903 ~ Tobago outer primaries, rectrices AMNH479329 05-28-1913 ~ Peninsula de Paria primary 6 AMNH 120418 05-31-1913 d' Peninsula de Paria outer rectrices (inner fresh) AMNH 120409 06-15-1913 d' Peninsula de Paria outer primaries; outer rectrices AMNH 120417 (inner fresh) 06-23-1998 d' Tobago head Hayes unpubl. data 06-28-1999 d' Tobago base of bill; primaties 9-10 Hayes unpubl. data 06-29-2000 d' Tobago head; primaries 9-10 Hayes unpubl. data 06-29-2000 d' Tobago head; primaries 9-1 0 Hayes unpubl. data 06-30-1999 d' Tobago primaries 6-10; P9 shorter, Hayes unpubl. data P6 shortest 06-30-1999 d' Tobago back Hayes unpubl. data 06-30-1999 d' Tobago head Hayes unpubl. data 06-30-1999 d' Tobago head, outer rectrices Hayes unpubl. data 07-04-1896 ~ Cordillera Central rectrices AMNH 68127 "AMNH = American Museum of Natural History; FMNH =Field Museum of Natural History

December 1997 had increased to 3.1 mm on 23 June sabre width for ageing males, for which more data 1998; the second with sabre with of 1.8 mm 011 22 were available, the proportion of immatures in the June 1998 had increased to 3.2 mm on 28 June 1999; post-hurricane Tobago population was higher, al­ and the third with sabre width of 1.85 mm on 28 though not significantly, than in the pre-hurricane June 1999 had increased to 3.3 mm on 6 August Tobago population (X2 = 0.88, df= 1, P = 0.35), but 2001 . The first two obviously increased sabre width was significantly higher than in all pre-hurricane during a single moult. Bill length did not differ be­ populations combined (x2 = 7.83, df= 1, P = 0.005). tween males with sabre widths< 2.3 mm (x = 25.0 mm, SD = 0.91, n = 51) and males with sabre widths DISCUSSION >2.3 mm (x =25.0 mm, SD = I .02, n = 63; t= 0.07, df = 112, p = 0.95). Geographic variation.-The morphological sim­ Based on the criterion of bill corrugations for ilarity among the three populations suggests that ageing, the proportion of immatures in the post­ none has been isolated long enough for substantial hunicalle population of Tobago was only slightly, phenotypic differentiation to occur. The variation but not significantly, higher than in the pre-hur­ in bill length and tail length among the three pop­ ricane population(·/= 0.07, df= 1, P= 0.80) and for ulations suggests directional selection or genetic all pre-hurricane populations combined (X2 = 0.48, drift. The longer tails of the post-hurricane male df= 1, P = 0.49; Table 5). Based on the criterion of population in Tobago may be an artifact caused by ------· ·------

Morphological Variation in the White-tailed Sabrewing 29

TABLE 5. Age structure of White-tailed Sabrewing populations, based on bill corrugations of both sexes and sabre width of males.

Population Immatures (%) Adults Bill corrugations (both sexes) Cordillera de Caripe (specimens) 5 (17.9) 23 Peninsula de Paria (specimens) 3 (27 .3) 8 Tobago (specimens, pre-hurricane) 3 (1 0.7) 25 All localities combined (specimens) 11 (16.4) 56 Tobago (live, post-hurricane, 1996-2001) 5 (21.7) 18 Sabre width (males only) Cordillera de Caripe (specimens) 9 (22.0) 32 Peninsula de Paria (specimens) 12 (52.2) 11 Tobago (specimens, pre-hurricane) 10 (50.0) 10 All localities combined (specimens, prehurricane) 3 1 (36 .9) 53 Tobago (live, post-hurricane, 1996-200 I) 24 (66.7) 12

the shrinking of tails in museum specimens (e.g., Hayes unpubl. data). Sexual dimorphism in bill Winker 1993 ), although directional selection is length appears related to sexual differences in plausible. Despite the morphological similarity foraging behaviour. Displaying male White-tailed among the three populations, substantial genetic Sabrewings usually forage for volant arthropods by differences may occur among isolated populations hawking, whereas females usually glean nonvolant of birds in the absence of morphological differ­ arthropods by gleaning vegetation (Hayes et al. in ences, such as in bird populations separated by the prep.).ln hummingbirds, Stiles ( 1995a) documented Amazon River (e.g., Capparella 1988, 1991). Al­ the correlation of short, straight bills with hawking though future genetic analyses could potentially and longer, curved bills with gleaning for arthro­ reveal significant genotypic differences among the pods. Relatively rapid bouts of hawking rather than three White-tailed Sabrewing populations, based prolonged bouts of gleaning may enable White­ on currently available information the White-tailed tailed Sabrewing males to spend more time defend­ Sabrewing should be regarded as a monotypic ing territorial leks (Hayes et al. in prep.). spec1es. Moult.-Hummingbirds typically undergo one Sexual dimorphism.-The White-tailed Sabre­ annual, post-breeding moult, although a few spe­ wing is sexually dichromatic, with males being more cies purportedly moult twice annually (Sick 1993). brilliantly coloured. Sexual dichromatism occurs in In the White-tailed Sabrewing, moult was recorded some, but not all, species of Campylopterus. The during the period of March-July, somewhat earlier larger body sizes of male White-tailed Sabrewings than that of most hummingbird species in Trinidad is typical of the larger species of hummingbirds, and Tobago (ffrench 1991), and apparently oc­ including other species of Campylopterus (Wet­ curred after the breeding season, which extends more 1968, Winker et al. 1992, Hayes unpubl. data), from January-April (Hayes et al . 2000). Because not presumably due to intrasexual competition favour­ all birds were moulti11g during March-July, moult ing larger body size in males and the energetic con­ may not occur annually. Ruschi (1973a, b) reported straints of reproduction limiting body size in fe­ that moult of the primary remiges of C. largipennis males (e.g., Johnsgard 1997). occurs every 2 yr, as in other species of Campylop­ The longer bill length of female White-tailed terus and in Eupetomena macroura. Although Sabrewings is typical ofmanyhummingbirds (Stiles moult-breeding overlap has been reported for 1995a), including most, but not all, species of hummingbirds (e.g., Stiles and Wolf 1974, Stiles Campylopterus (Wetmore 1968, Winkeret al. 1992, 1985), it remains unclear whether it ever occurs in 30 HAYES the White-tailed Sabrewi11g. Because many males with narrow sabres lacked bill In a study of 13 species of hummingbirds in corrugations, the colll.lgations obviously disappear Costa Rica, Stiles ( 1995b) found the sequence of long before sabrewings develop widened sabres. moult for individual feathers to be highly consis­ Whether widened sabres appear during the first tent for the primaries, but more variable for the primary moult at about 1 yr of age or in the second secondaries, rectrices and body. ln the White-tailed moult at 2 yr remains uncertain and requires addi­ Sabrewing, the overlap of primary and rectJix moult, tional field work. Nevertheless, the delayed appear­ and tl1e moult of inner rectrices prior to outer rec­ ance of widened sabres indicates that they may be trices, are typical of hummingbirds (Stiles 1995b). regarded as secondary sex characters. Nevertheless, considerably more data are needed to It is often stated that only three outermost document the sequence of moult in individual primaries of Campylopterus are sabre-shaped (e.g., feathers of the White-tailed Sabrewing. Johnsgard 1997). However, we have noted up to Population age structure.-The presence of bill five widened primaries in adult male White-tailed corrugations is diagnostic for immature humming­ Sabrewings. Although the White-tailed Sabrewing birds, in which smoothing may take up to 9 months possibly has more sabre-shaped primaries than do (Ortiz-Crespo 1972) but usually less, such as 6 other species of Campylopterus, variation in other months in large hermits (Stiles and Wolf 1979). species probably has been overlooked. Breeding activity has been recorded during Jan­ Based on sabre widths of males, the post­ uary-April in Tobago (Hayes et al. 2000), but no hurricane (1996-1998) proportion of adults and im­ data are available from Venezuela. Immature speci­ matures in the Tobago population does not differ mens with bill corrugations taken from I 0 February significantly from the pre-hunicane population, to 5 March in Venezuela may have been nearly a suggesting a demographically stable population. year old, unless breeding occurs later in Venezuela. However, the sample sizes were small. The higher Bill length has been used as an indicator of age proportion of immatures in post-hurricane Tobago in hummingbirds (Zimmer 1952), but apparently compared with all pre-hunicane populations com­ requires large series for accurate measurements and bined suggests that the population in Tobago is comparisons and is useful only for comparisons of still increasing. Sabre width as a method for ageing juveniles and young immatures vs older immatures may be used for long-te1m monitoring of the Toba­ and adults (Ortiz-Crespo 1972). ln the White-tailed go population to evaluate demographic trends. Sabrewing, bill length does not appear to be a re­ Sabre function.- The function of the sabre­ liable indicator of age class; however, the sample shaped primaries of Campylopterus is poorly sizes of specimens with conugations on the bill known. Johnsgard (1997:23) suggested that the were small. widened sabres are "possibly related to a general The sabre width of male White-tailed Sabre­ strengthening of the outer primaries or perhaps for wings also appears to be a reliable indicator for two some unknown display purposes." However, age classes, ranging from 1.5-2.2 mm in immatures strengthening of the wings seems unlikely since and 2.5-3.55 mm in adults. The abse11ce of inter­ other hummingbirds lack such thickened primary mediate-width sabres and direct evidence of sabre shafts. width changing from < 2 to > 3 mm during a single I propose three hypotheses for sabre function . moult in banded individuals indicates that wide First, wide sabres may confer a competitive advan­ sabres are acquired abruptly from one feather gen­ tage over less endowed males dming male-male eration to the next, rather than gradual1y through a conflicts (sabre-rattling hypothesis). Possible ad­ series of moults. However, the age at which sabre­ vantages of wide sabres include increased sound wings develop widened sabres is unknown. Gilliard production, a different sound frequency, faster (1941: 470-471) commented that 'There is some flight a11d tighter turns, which may intimidate doubt as to when the 'crooked wing' first replaces younger or less endowed competitors during male­ the straight shaft. Mr. Zimmer thinks it is acquired male chases. Second, females may prefer to mate not as a post-juvenile change but pre-nuptia1ly." with males possessing the widest sabres, which are Morphological Variation in the White-tailed Sabrewing 31

TABLE 6. Comparison of predictions supporting (+)or not supporting (-) three hypotheses (see Discussion section) for sabre function.

Prediction for wide-sabred dd Sabre rattling Sabre flashing Sabre sickling 1. Faster flight + + + 2. Tighter turns + + + 3. Greater sound production + + 4. Different sound frequency + + 5. Defend lek territories + + 6. Win d-d' conflicts + 7. More attractive to 'i' 'i' + 8. Mate more frequently with 'i' 'i' + 9. Father more offspring + 10. Greater success foraging on arthropods + inherently more attractive (sabre-flashing hypoth­ difficult because of the high-speed flight of males esis). The females may be attracted by the greater through the vegetation during prolonged chases. sound production, a different sound frequency, Testing whether females prefer wider-sabred males faster flight, tighter turns, or simply the appearance (#7) would probably require choice experiments in of wide-sabred (i.e., ornamented) males. And third, captivity. Although mating has not been observed wide sabres may enhance the efficiency of aerial during roughly 14 days of intense observation at foraging on arthropods (sabre-sickle hypothesis). White-tailed Sabrewing leks (Hayes et al. in prep.), By reinforcing the wing, the wider sabres may en­ given enough time the frequency of matings (#8) able males to fly faster and make tighter turns when could be observed in the field. DNA fingerprinting hawking for arthropods, which may be particularly of blood samples could determine which birds economical for males defending lek territories. father the most offspring (#9). Determining the The three hypotheses may not be mutually success rates of foraging on arthropods (#I 0) exclusive. For example, enhanced foragi11g (sabre­ would be difficult to study because the arthropods sickle hypothesis) may confer a competitive advan­ taken are too small to observe in the field. tage during male-male conflicts (sabre-rattling Thus far none of these predictions have been hypothesis), which in tum may be more attractive adequately tested. However, because only adult to females (sabre-flashing hypothesis). males possess widened sabres, a role in sexual Each hypothesis may be supported by a set of selection is strongly implied. The breeding system predictions; in many cases, a prediction may sup­ of the White-tailed Sabrewing is characterized by pmi more than one hypothesis (Table 6). Several lek polygyny (Hayes et al. 1997b, 2000, in prep.). predictions (enumerated as in Table 6) may feasibly Sexual dimorphism occurs in most, but not all, be tested on individually marked sabrewings (e.g., species of animals known to display in leks Stiles and Wolf 1973) of known sabre width, but (Hoglund and Alatalo 1995). Lekking has been only during extensive field work. A radar detector recorded in a variety of hummingbirds (see recent could be used to measure flight speed (#I). Video reviews by Johnsgard 1994, Hoglund and Alatalo footage could be used to evaluate the tightness of 1995), particularly in species of the genus Phae­ turns during flight (#2). Sophisticated sound­ thornis, which lack marked sexual dimorphism (e.g., recording equipment could be used to measure Stiles and Wolf 1979). The reviews by Johnsgard sound production (#3) and sound frequencies (#4) {1994) and Hoglund and Alatalo (1995) cited evi­ during flight. Measurements of sabre widths of dence for lekking in just one species of Campy­ lekking birds could evaluate prediction #5. Deter­ lopterus, the Violet Sabrewing (C. hemileucurus). mining the winner of male-male conflicts (#6) is However, a further review ofthe literature revealed 32 HAYES

TABLE 7. Evidence for lek polygyny in sabrewing hummingbirds (Campylopterus spp.) and allied taxa recently merged with Campylopterns (Schuchmann 1999).

Species Evidence for lekking Source(s) Wedge-tailed Sabrewing• up to 15 0'0' singing and displaying M. T. Gordon pers. comm. Campylopterus curvipennis Long-tailed Sabrewing• up to 3 0'0' singing and displaying Winker eta!. (1992) Campylopterus excellens Gray-breasted Sabrewing up to 3 0'0' singing and displaying Hilty and Brown (1986) Campylopterus largipennis Rufous Sabrewing 2 0'0' singing Skutch (1967) Campylopterus rufus Rufous-breasted Sabrewing none reported Campylopterus hyperythrus Buff-breasted Sabrewing none reported Campylopterus duidae Violet Sa brewing up to 10 0'0' singing and displaying Stiles and Skutch (1989) Campylopterns hemileucurus White-tailed Sabrewing up to 4 0'0' singing and displaying Hayes eta!. (1997, 2000) Campylopterus ensipennis year-round at traditional sites Lazuline Sabrewing none reported Campylopterus falcatus Santa Marta Sabrewing 2 0'0' singing (one singing "in answer Todd and Carriker (1922) Campylopterusphainopeplus to its mate", presumably another if) Napa Sabrewing none reported Campylopterns villaviscensio Scaly-breasted Hummingbird up to 8 0'0' singing and displaying Stiles and Skutch ( 1989) Phaeochroa cuvierii Sombre Hummingbird none reported Aphantochroa cirrochloris Swallow-tailed Hummingbird "well known among hummingbird K.-L. Schuchmann pers. Eupetomena macrourus specialists working in Brazil" comm. "possibly conspecific (American Ornithologists' Union 1998, Schuchmann 1999) evidence for lek polygyny (based on the criterion Sabrewings. However, Todd and Carriker (1922:270) of males displaying in groups of two or more; referred to "the well known burr-rr of the wings" of Hoglund and Alatalo 1995) in at least seven of 11 the Santa Marta Sabrewing (C. phainopeplus). species of Campylopterus, plus in an additional Dickey and Van Rossem (1938:273) described "the two of three species recently merged into Campy­ characteristic buzz" of the Rufous Sabrewing (C. lop tents (Table 7). Thus, lek polygyny appears to rufus) as "rather soft and deep-toned", which be widespread in this genus (possibly occurring in "lacks the sharp quality of most of the small hum­ all species), which further supports the hypothesis mers". In Brazil, Ruschi (1973a:51 [English], 1973b:2 that sabre-shaped primaries provide an important [Portuguese]) described courtship in the Gray­ function in sexual selection. breasted Sabrewing (C. largipennis) as the male With regard to sound production, neither I nor encircling the perched female "in heavy librarian any of my field assistants have ever noted any {sic] flight, with tail held open showing the large unusual sounds produced by flying White-tailed white band on the tips of the tail feathers"; Morphological Variation in the White-tailed Sabrewing 33

simultaneously "the wings, in slow beats, produce dete1mined. Genetic studies in progress may even­ a characteristic tnT, trr, ttT, sound which adds tually elucidate relatedness and reproductive suc­ greatly to the display". Although anecdotal, this cess among individual birds, which may shed fur­ observation supports the sabre flashing hypoth­ ther light on sabre function in the White-tailed esis. Sabrewing (Benes and Hayes in prep.). In Campylopterus hummingbirds, tail fanning may represent a display with a role in sexual select­ ACKNOWLEDGEMENTS ion. In addition to the display cited above, others have noted tail flashing during displays. In the Field work in Tobago was financially supported Santa Marta Sabrewing, Todd and Carriker (1922: directly or indirectly by the American Bird Con­ 270) noted that one would occasionally "shoot up servancy, Amoco Trinidad Oil Company, Andrews into the air like a rocket, sound a very pretty twit­ University, BirdLife International, British Petroleum, twit, tum a few somersaults, and descend grace­ Caribbean Union College, Center for the Study of fully with tail-feathers spread out like a fan". In the Tropical Birds, Fauna and Flora International, Field Violet Sabrewing, Slud (1964: 147) noted that "The Museum of Natural History, Guardian Life of the large white area on its rectrices is flashed when the Caribbean Limited, Lincoln Park Zoo, Lorna Linda bird shear-flicks its tail and is conspicuous in University, Republic Bank Limited, Sigma Xi, flight". Skutch (1967:20) fmiher observed that a Trinidad and Tobago National Petroleum Marketing displaying male would "spread his tail fanwise for Company Limited, and Trinmar Limited. Further a brief instant, sending forth a transient flash of financial suppmt was provided by the sales ofT­ white. More rarely, he held his tail spread out for a shirts with a painting of Wl1ite-tailed Sabrewings second or two, while he vibrated it rapidly in a generously donated by Joh11 P. O'NeilL Thus far striking display. Occasional pursuits ... were also about 100 students and professionals representing accompanied by much flashing of the white outer 14 countries have assisted me with field work in tail feathers." Tobago. Neither I nor my field assistants have ever Specimen and literature research in American observed mating in the White-tailed Sabrewing, but museums was funded by a travel grant from the have often observed males chasing both males and University of the West Indies. For facilitating ac­ females. Chases are generally high speed and the cess to museum specimens and stimulating discus­ tail is frequently fanned, thus exposing the three sion on sabre function, I thank C. Griffiths of the white outermost rectrices. When perched in a tree, American Museum of Natural History and M. males periodically lean forward, stretch their wings Foster, G. Graves and R. Zusi of the National and fan the tail; this often, but not always, pre­ Museum ofNatural History. Specimens were kindly cedes a flight. However, it remains uncertain wheth­ loaned by S. Hackett of the Field Museum of er this behaviour represents a display or merely Natural History. Specimen data were kindly sup­ stretching. plied by M. Adams of the British Natural History Thus far I have documented four wide-sabred Museum, K. Garrett of the Los Angeles County males and two narrow-sabred males actively dis­ Museum, and M. Lentino of the Colecci6n Omi­ playing at White-tailed Sabrewing leks (Hayes et al. tol6gica Phelps. I thank K. Winker, F. G. Stiles, and in prep.). This indicates that young males are capa­ R. L. Zusi for reviewing the manuscript. K.-L. ble of defending a lek territory which seemingly Schuchmann and M. T. Gordon kindly provided negates the sabre rattling and sabre flashing hy­ unpublished information. Finally, I am indebted to potheses. However, young males of other lekking K. Winker for first encouraging me to measure hummingbird species also display at the lek but sabre widths and to study their function. likely have little chance of mating since they oc­ cupy subordinate positions (Stiles and Wolf 1979). LITERATURE CITED Obviously much more detailed studies are required before the true function of widened sabres can be BEHNKE-PEDERSEN, M. 1972. Kolibrier. Bind. I. 34 HAYES

Skibby-BColombia. Princeton University Trust Board, Wellington. Press, Princeton, New Jersey. 836 pp. CHEW, V. 1977. Comparisons among treatment HOGLUND, J., AND R. V. Al.ATALO. 1995. Leks. means in an analysis of variance. Agricultural Princeton University Press, Princeton, NJ. 248 Research Services of the U. S. Department of pp. Agriculture, Hyattsville, MD. 64 pp. JOHNSGARD,P.A.l 997. ThehummingbirdsofNorth COLLAR, N. J., L. P. GONZAGA, N. KRABBE, A. America. 2nd. ed. Smithsonian Institution Press, MADRONO NIETO, L. G. NARANJO, T. A. PARKER, Washington, DC. 278 pp. Ill, AND D. C. WEGE. 1992. Threate11ed birds of ORTIZ-CRESPO, F. I. 1972. A new method to sep­ the Americas. The ICBP/IUCN red data book. arate adult and immature hummingbirds. Auk 3rd ed., pt. 2. International Council for Bird 89:851-857. Preservation [now BirdLife International], Cam­ PAYNTER, R. A., JR. 1982. Omitho1ogical gazetteer bridge, UK. 1150 pp. of Venezuela. Museum of Comparative Zool­ DICKEY, D. R., AND A. J. VAN ROSSEM. 1938. The ogy, Harvard University, Cambridge, MA. 245 birds ofEI Salvador. Field Mus. Nat. Hist. Zoo!. pp. Ser. 23:1-609. RIDGEWAY, R. 1892. The hummingbirds. Rept. U.S. FFRENCH, R. P. 1975. Some noteworthy bird records Nat!. Mus. 1890:253-383. from Tobago. J. Trin. To b. Field Nat. Club 1975: RUSCHI, A. 1973a. Beija-flores (hummingbirds). 5-11. Museu de Biologia "Prof. Mello Leitao", Santa FFRENCH, R. P. 1991. A guide to the birds of Trin­ Teresa, Brasil. idad & Tobago. 2nd edition. Cornell University RUSCH!, A. 1973b. Algumas observa<;:oes sabre: Press, Ithaca, NY. 426 pp. Campylopterus largipennis aequatorialis GILLIARD, E. T. 1941. The birds of Mt. Auyan­ Gould, 186 1. Bol. Mus. Biol. "Prof. Mello Tepui, Venezuela. Bull. Amer. Mus. Nat. Hist. Lei tao", Ser. Zoo!. 46:1-2. 77:439-508. SCHUCHMANN, K.-L. 1999. FamilyTrochi1idae (hum­ HAYES , F. E., A. L. BULLARD, D. R. HARDY, D-A. D. mingbirds). Pp. 468-680 in Handbook of the WILSON, D. J. WILSON, T. 0. GARNETT, M. V. birds ofthe World (J. del Hoyo, A. Elliott and J. BERNARD, B. Y. Y. WONG, H. S. GURLEY, v. L. Sargatal,eds.). Vol. 5. Lynx Editions, Barcelona. JOSEPH, AND M. M. HAYES. 1995. White-tailed SICK, H. 1993. Birds in Brazil: a natural history. Sabrewing population recovering on Tobago. Princeton University Press, Princeton, NJ. 703 Cotinga 4:7. pp. HAYES, F. E., T. 0. GARNETf, M. V. BERNARD, AND SLUD, P. 1964. The birds of Costa Rica: distribution I. SAMAD. 1997a. Update on the status of the and ecology. Bull. A mer. Mus. Nat. Hi st. 128: l - threatened White-tailed Sabrewing (Campy­ 430. lopterus ensipennis) on Tobago, West I11dies. SKUTCH, A. F. 1967. Life histories of Central Am­ Pitirre I 0(1 ):28. erican highland birds. Pub!. Nuttall Ornithol. HAYES, F. E., T. 0 . GARNEIT, M . V. BERNARD, A. L. Club 7:1-213. BULLARD, D. R. HARDY, D-A. D. WILSON, D. J. STBLEY, C. G., AND B. L. MONROE, JR. 1990. Distri­ WtLSON, v. L. JosEPH, AND D. K. ST. Lours. bution and taxonomy of birds of the World. -"------·-----·-- ---·--·------

Mo1phological Variation in the White-tailed Sabrewing 35

Yale University Press, New Haven, CT.llll pp. APPENDIX STILES, F. G. I 985. Seasonal patterns and co-evo­ lution in the hurnrningbird-flowercommunityof White-tailed Sabrewing specimens examined by a Costa Rican subtropical forest. Omithol. myself or others (see Acknowledgements). AMNH Monogr. 36:757-787. =American Museum ofNatural History, New York, STILES, F. G. 1995a. Behavioral, ecological and USA; BMNH = Natural History Museum (formerly morphological correlates of foraging for arthro­ British Museum of Natural History), Tring, UK; pods by the hummingbirds of a tropical wet COP = Colecci6n Omitol6gica Phelps, Caracas, forest. Auk 97:853-878. Venezuela; FMNH = Field Museum of Natural STILES, F. G. 1995b. Intraspecific and interspecific History, Chicago, USA; LACM = Los Angeles variation in molt patterns of some tropical hum­ County Museum, Los Angeles, USA; USNM = mingbirds. Auk 112:118-132. United States National Museum of Natural History, STILES, F. G., AND A. F. SKUTCH. 1989. A guide to Washington, DC, USA. the birds of Costa Rica. Comell University Press, Ithaca, NY. 511 pp. CORDILLERA DE CARIPE, VENEZUELA STILES, F. G., AND L. L. WOLF. 1973. Techniques for Bergantin, Sucre: COP 15428; Campo Alegre color-marking hummingbirds. Condor 75:244- [labelled 'Campos Alegre Valley'], Sucre: AMNH 245. 479337,479338,479339,479340,4793410,479342; STILES, F. G., AND L. L. WOLF. 1974. A possible Carapas, Sucre: AMNH 188188, 188189; Caripe, circannual molt rhythm in a tropical humming­ Monagas: BMNH 1887.3.22.258, COP 22899; Cerro bird. A mer. Nat. 108:341-354. Negro,Monagas/ Sucre: COP 22900,22901,22902, STILES, F. G., AND L. L. WOLF. 1979. Ecology and 22903,22904,22905,22906,22907,22908,22910, evolution of lek mating behavior in the Long­ 22911,22912,22913,22914,22915,22916;Cerro tailed Hermit hummingbird. Ornithol. Monogr. Peonia, Sucre: COP 15427; Cerro Turumiquire, 27:1-78. Sucre: COP 65882, 65883, 65884, 65885, 65886, TODD, W. E. C., AND M.A. CARRfKER, JR. 1922. The FMNH 91901,91902,91903,91904,91906,91907, birds of the Santa Marta region of Colombia: a 91908; Cumanacoa, Sucre: AMNH 68127, 73494, study in altitudinal distribution. Ann. Carnegie 73495, LACM 72705; El Guacharo [labelled 'Mon­ Mus. 14:1-611. tafia del Gm1charo'], Monagas: AMNH 70370, WETMORE, A. 1968. The birds of the Republic of USNM 70371; La Tigrera, Sucre: AMNH 479348; La Panama. Part 2.-Columbidae (pigeons) to Pici­ Trinidad, Boca [mouth], Sucre: COP 65887, 65888, dae (woodpeckers). Smithsonian Institution 65889,65890,65891, 65892; Los Palmales, Sucre: Press, Washington, D. C. 605 pp. A:I\1NH 70372, 70374, 479345, USNM 70373; WrNKER, K. 1993. Specimen shrinkage in Tennessee Villarroel [labelled 'Quebrada Seca'], Sucre: AMNH Warblers and "Traill's" Flycatchers. J Field 479344; Rincon de San Antonio, Sucre?: AMNH Omithol. 64:331-336. 479346; Santa Ana [labelled 'Santa Ana Valley'], WINKER, K. W., M. A. RAMOS, J. H. RAPPOLE, AND Sucre: AMNH 479347 D. W. WARNER. 1992. A note on Campylop­ terus excellens in southern Veracruz, with a PENINSULA DE PARIA, VENEZUELA guide to sexing captured individuals. J. Field Cmiaquito, Sucre: COP 7581 0; Cerro Azul, Macuro Omithol. 63:339-343. [labelled 'Cristobal Colon'], Sucre: AMNH 120409, ZAR, J. H. 1984. Biostatistical analysis. 2nd ed. 120411,120412,120413,120414,120416,120417, Prentice-Hall, Inc., Englewood Cliffs, NJ. 718 pp. 120418,120419,120420, 120422,COP43936,43937, ZlMMER, J. T. 1952. Studies of Peruvian birds. No. 43938,43939,43940,43941,43942,43943,43944, 62. The hummingbird genera Patagona, Sap­ 43945; Ceno Azul, Falda 0. [east flank], Sucre: pho, Polyonymus, Ramphomicron, Metallura, COP43946, 43947,43948,43949,43950,43951,43952, Chalcostigma, Taphrolesbia, and Aglaiocer­ 43953, 43954;Cerro Azul, La Cumbre [summit], cus. Amer. Mus. Novit. 1595:1-29. Sucre: COP 40466,40467, 40468; Cerro Humo, Sucre: 36 HAYES

COP 41015, 41015.A; Cerro Humo, Falda 0. [east 479335, 479336, BMNH unregistered (three speci­ flank], Sucre: COP 44165, 44166; Uquire, Sucre: COP mens), 1914.1.10.2, FMNH 42534,42535,42536, 75807,75808,75809 42537,42538,42539, USNM 74916

TOBAGO LOCALITY UNKNOWN Castara: AMNH 479326,479327, 479328, 479329; AMNH 129094, 437450; BMNH unregistered (four Englishman's Bay: AMNH 479331, BMNH un­ specimens), 1887.3.14.43 [Trinidad], 1913.3.20.114 registered; Mondland: AMNH 479330; Parrott Hall: [Trinidad], 1887.3.22.259 [Venezuela]; FMNH45745 AMNH479332, 479333; Richmond: AMNH 479334; [Trinidad], 45746 [Trinidad], 124422 [Westin dies]; no locality: AMNH 52 [field number], 34184,37180, USNM 84152 [Bahia], 84540 [Trinidad], 149329 37181,37182,37183,37185, 86930, 129092, 129093, [Trinidad] Pp. 37-44 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. 1 J, 2002.

IS THE RING-NECKED SEEDEATER (SPOROPHILA INSULARIS) FROM TRINIDAD EXTINCT, OR IS IT A CRYPTIC SPECIES WIDESPREAD IN VENEZUELA?

ROBIN L. RESTALL Collecci6n Ornitologica Phelps, Caracas, Venezuela and c/o Aerocav 1330, P.O. Box 025304, Miami, FL 33102-5304, USA

ABSTRACT.-Sporophila intermedia insularis was described as a subspecies of the Gray Seedeater in 1946 from a specimen collected in Ttini dad, but was s yn on yrnized with S. i. intermedia in 1952. Based on a reanalysis of museum specimens and live birds captured recently in the field, I found that 3 7 adult male specimens of insularis differed consistently from S. i. intermedia by several plumage traits and bill colouration. Furthermore, bill size, tarsus length and body mass were significantly greater in insularis. Because the two taxa occur syrnpatrically in Trinidad (possibly extirpated) and throughout Venezuela north of the Orinoco River, I propose that S. insularis should be recognised as a distinct, cryptic species, given tl1e English name of Ring-necked Seedeater and Spanish name Espiguero Collarblanco.

RESUMEN .-En 1946, Sporophila intermedia insularis fue descrito como una subespecie del Espiguero Pico de Plata basado en un especimen colectado en Trinidad, pero en 1952 fue sinonimizado conS. i. intermedia. Basandome en un nuevo an ali sis de ejemplares de museo, y de ejemplares vivos capturados recientemente en el campo, he encontrado 37 machos adultos de insularis que se diferencian consistentemente deS. i. intermedia en varias caracterfsticas de plumaje y color del pico. Mas atm, el tamafio del pico, Ia longitud del tarso, y la masa corporal son significativamente mayores en insularis. En vista de que las taxa ocurren simpatricamente en Trinidad (donde posible­ mente han sido erradicados) y por todo Venezuela a! norte del Orinoco, propongo el reconocimiento de S. insularis como una especie distinta, criptica, con el nombre en ingles de Ring-necked Seedeater yen espafiol de Espiguero Collarblanco.

KEY WORDS.-cryptic species, distribution, Gray Seedeater, morphology, plumage, Ring-necked Seedeater, Sporophila intermedia, Sporophila insularis, taxonomy, Trinidad, Venezuela

The Gray Seedeater (Sporophila intermedia) habitat disturbance or extreme weather conditions. is widespread in Colombia, Venezuela and T1inidad Like most species of Sporophila, it is a stem glean­ (Ridgely and Tudor 1989). It is primarily a lowland er, taking seeds from grasses and forbes on the species, but wanders up to lower subtropical levels. stem, but its feeding strategy is flexible. It has been lt is generally considered a resident, somewhat sed­ observed hawking termites and other succulent, entary species (Thomas 1996); most movements are slow flying alates (Sick 1993, Thomas 1996, pers. probably due to either dispersal of young birds, obs.). It will also take buds and stems of tender

37 38 REsTALL

"

FIG. 1. Geographical distribution of Gray Seedeater (Sporophila intermedia), indicated by shading based on Ridgely and Tudor (1989), and Ring-necked (S. insularis), indicated by dots (see localities in Appendix). leaves, and under some circumstances will take Surprisingly Gilliard and apparently all others fallen seed from the ground (pers.obs.). who examined Gray Seedeater specimens failed to The Gray Seedeater was long considered a notice the white bar across the rump of insularis, monotypic species until Gilliard (1946) examined a resembling the apparent bar that occurs when the full series and noticed that there were birds with pale feathers of the flanks are laying up under the post-auricular whitish patches on the sides of the wings and almost join across the lower rump. In the neck. When arranged geographically, these birds case of nominate intermedia, these can be brushed clustered into two groups, each at the extreme ends back into position to leave the lower rump all grey, of the species' distribution. Gilliard (1946) first de­ but in insularis the white is in the actual lower scribed the birds from Trinidad, the type from rump feathers. My attention was drawn to this by Princes Town, naming them S. i. insularis. He then a careful examination of some baldy marked speci­ described some darker birds from Cauca, south­ mens of insularis in the Colecci6n Omito16gica western Colombia, as S. i. bogotensis. The inter­ Phelps (COP), Caracas, that had been collected in veni11g population was retained as nominate S. i. the Delta Amacuro of Venezuela. intermedia. However, in a subsequent revision of A thorough review of the full series of S. i. Sporophila, Meyer de Schauensee ( 1952) synon­ z'ntermedia in COP resulted in the discovery that ymized insularis with nominate intermedia. This several males labelled as nominate intermedia pos­ was later accepted by Storer (in Paynter 1970). sessed a white bar across the rump, together with Thus, insularis was relegated to taxonomic obliv­ some degree of white or light grey on the throat; wn. these specimens were diagnosable as Gilliard's S. i. Ring-necked Seedeater (Sporophila insularis) 39

was obtained from specimen labels or measured in the field. Student's t tests (t statistic; Sokal and Rohlf 1981) were used to compare differences between S. intermedia and S. insularis for each 3 variable. I also estimated bill volume (mm ) of each species using the tetrahedron formulae (Blonde! et al. 1984).

RESULTS

Geographical distribution.-s. insularis has been collected in Trinidad and throughout Vene­ zuela north of the Orinoco, where it occurs sym­ patrically with S. i. intermedia (Fig. l ). Plumage and soft parts.-In S. i. intermedia, the male is uniform medium or dark grey from the FIG. 2. Type specimen (left) and white-throated forehead to the uppertail coverts. The colour is vmiant (right) of male Ring-necked Seedeater somewhat variable depending on the age of the (Sporophila insularis). See monograpl1 cover for bird, with older birds being a more intense and colour portrait. The white band across the rump is deeper slate grey. The tail and wings are fuscous to normally concealed as the wings are usually carried blackish with fine grey edges to the greater wing flush along the back. coverts and remiges, and there is a small white speculum on the base of the inner primaries. The underwing coverts are mostly white with dark cen­ insularis. Subsequent field trips to the Venezuelan tres in the outer coverts and the outermost coverts llanos resulted in several examples of insularis be­ being completely dark grey. The head completely ing mist-netted. In this paper I reevaluate the status lacks white. It is usually a lighter grey from the chin of S. i. insularis, which I tentatively recognise as a downward to the breast and flanks. This grey mer­ distinct species, the Ring-necked Seedeater (S. ges into the ivory white of the underparts, be­ insularis). coming more cleanly divided and contrasting with advanced age. The bill is pale and generally pinkish MEnmos buff, occasionally with brownish streaks, and usu­ ally with slightly yellowish cutting edges. I have Based on museum specimens (see Acknowl­ not seen a live adultS. i. intermedia male with the edgements) and recently captured live individuals, dark, purplish grey on the maxilla that seems to oc­ I examined plumage and soft part colouration of 92 cur with some regularity on the bill of S. insularis. adult maleS. i. intermedia and 37 (five live) adult The legs, feet and toes and toes are slate-grey to maleS. insularis (see Appendix). Colour references blackish, and the toenails are dark brown or black­ follow those used by Ridgway (1912). ish. To compare morphological differences be­ The female intermedia is brown above and tween the two taxa, I measured each bird with a also on the breast and flanks, which have a distinct Helios digital caliper. Measurements (mm) taken warm tone. The belly and undertail coverts are i11clude: exposed culmen length; bill length from white with a huffy tinge. The underwing coverts nostril to tip ofmaxi Jar; bill height in an axis running bave the same pattern as that of the male. The bill vertically through the nostril; bill width at the base i.s dark brown, appearing black. The legs, feet and from one side of the inner extremity of the mandib­ toenails are vinaceous grey to vinaceous slate. It is ula to the other; wing chord length; tail length; and slightly smaller than the male but has a slightly tarsus length (Baldwin et al. 193 1). Body mass (g) more massive bill. 40 RESTALL

FIG. 3. Heads of grey seedeaters to show comparative amounts of white on throat and neck. ( l) white­ throated variant of Ring-necked Seedeater (Sporophila insularis); (2) typical S. insularis; (3) Gray Seedeater (S. intermedia); (4) Slate-colored Seedeater (S. schistacea) with white on sides of throat, not post-mesial or post-auricular; and (5) Plumbeous Seedeater (S. plumbea) with dark bill.

The type specimen of S. insularis was de­ A diagnostic plumage character not mentioned scribed from Princes Town, Tri11idad, as "similar to by Gilliard but present in all insularis specimens S. i. intermedia of Venezuela, but adult males with that I have examined is a soft white bar across the whitish post-auricular patches" and "sides of lower rump. Also, the outer underwing coverts tend throat immediately posterior to auriculars strongly to be pale grey, or white in the more strongly tipped with white" (Gi1liard 1946:571 ). Gil1iard ex­ marked individuals. This apparently applies to the amined 14 males from Trinidad, of which 12 con­ females as well. fotmed to the type description. A white-throated The type specimen and a white-throated var­ variant possessed "broad white margins on sides iant of maleS. insularis are depicted on the mono­ of throat; throat and chin wl1iter than in any other graph cover (colour portrait) and in Fig. 2. The vari­ bird in the extensive series; inner median upper­ able amount of white in the throat and neck of male wing-coverts tipped with white" (Gilliard 1946:571 ). S. insularis is illustrated and compared with other An immature specimen (P. Sweet pers. comm.) had Sporophila species in Fig. 3. no white post-auricular tipping. Gilliard also con­ Morphometries. -ln compatison with S. inter­ strued from the specimens that the bill of S. media, S. insularis averaged significantly larger in insularis was a darker pink with a cinnamon wash, bill size (culmen length, bill height and bill width), especially noticeable on the maxilla. However, this tarsus length and body weight, but there were no was impossible to tell from old specimens with differences in bill length from nostril, wing length accuracy. The bills of live male S. insularis that I and tail length (Table l ). The calculation of bill vol­ l1ave examined seem to be a more greyish pink, ume using mean data revealed average volumes of actually a light cinnamon drab with deep cinnamon 107.1 mm3 for S. intermedia and 124.63 mm3 for S. buff cutting edges. I have noticed in live birds a insularis, a difference of 16.4%. streaking of dark purplish grey on the maxilla, which may be extensive; in one bird dark purplish DISCUSSION grey covers the entire maxilla except the cutting edge. This may also occur on the base of the man­ My initial hypothesis was that insularis sim­ dible. I suspect this trait may be usually if not ply represented plumage and morphological vari­ always present in insularis. In contrast, the bills of ation within S. intermedia. This was the conclusion all live adult male intermedia I have examined have of Meyer de Schauensee (1954), Junge and Mees been generally pinkish buff, occasionally with (1958), Herklots (1961), ffrench (1973, 1991) and brownish streaks, with slightly yellowish cutting Stiles ( 1996). However, my reanalyses revealed con­ edges. sistent differences in plumage and soft part traits as Ring-necked Seedeater (Sporophila insularis) 41

TABLE 1. Morphological measurements (mm) and body mass (g) of male Gray Seedeater (Sporophila intermedia) and Ring-necked Seedeater (S. insularis), with results of Student's t tests comparing differences between the two taxa.

Sporophila intermedia Sporophila insularis Variable X (SD) Range (n) x (SD) Range (n) Bill length from nostril 7.23 (0.38) 5.79-8.14 (98) 7.36 (0.36) 6.59-8.11 (37) Exposed culmen length 9.87 (0.48) 8.77-10.89 (100) I 0.43 (0.46)b 9.49-11.35 (35) Bill height at nostril 8.20 (0.35) 7.56-9.07 (99) 8.68 (0.5l)b 7.94-9.89 (35) Bill width at gape 8.01 (0.68) 7.14-9.02 (99) 8.26 (0.46)" 6.63-9.10 (35) Tarsus length 15.17(0.93) 11.7-17.11 (103) 16.18 (1.25)b 14.36-19.7 (36) Wing chord length 56.37 (1.77) 51.36-59.84 (102) 56.24 (2.36) 49.96-61.64 (36) Tail length 43 .13 (1.97) 38.43-49.06 (102) 44.02 (2.74) 37.47-52.13 (36) Body mass 11 .24 (0.82) 10.0-13 .0 (19) 13.4 (1.56t 11.0-15.0 (5) "differs from S. intermedia, P < 0.01 bdiffers from S. intermedia, P < 0.001 well as statistically significant morphological dif­ aris. On several occasions I have seen S. insularis ferences between the two taxa. Furthermore, their (identity confirmed by mist-netting the individuals) sympatry suggests an obvious alternative hypoth­ foraging among the slender outer branches of small esis that insularis is a sibling (Mayr 1963, 1982) or trees, searching beneath leaves in a similar manner cryptic species (Paterson 1993). to that associated with warblers and Bananaquits The two taxa differ morpho logically in bill size, (Coereba flaveola). In addition, there is the pos­ tarsus length and weight. Although bill size may sibility tl1at S. insularis has a more terrestrial forag­ function in sexual selection, as in Asian munias ing strategy. This has been demonstrated as a cor­ (Restall 1995), the most likely explanation is that relate with length of tarsus in a comparative context each taxon may have a marginally different feeding between different subspecies of Lesser Antillean ecology. The larger bill of S. insularis suggests it Bullfinch (Loxigilla noctis; Bird 1983). It is certain may be feeding, at least in part or at certain times of that S. insularis will also forage on the ground, the year, on larger or harder seeds. This deduction albeit rarely (pers. obs.). Obviously further behav­ is supported by a comparative study of sympatric ioural studies of the two taxa are needed. ground doves and Sporophila seedeaters in the That two closely related and morphologically Venezuelan llanos (Perez 1999). Jn this study, the similar grassland finches can appear to be fully congeners fed on the same assortment of seeds sympatric in every sense yet occupy different and other foods until tl1e dry season caused short­ foraging niches is comparable to the Black-faced ages of certain favoured seeds. At this time, the Grassquit (Tiaris bicolor) and Yellow-faced Grass­ species with larger bills tended to feed on larger quit (T olivacea), which are sympatric in parts of seeds and those with sma11er bills fed on smaller their ranges in the West Indies (Pulliam 1969). seeds . This was true for both the doves and seed­ Where they both occur in Jamaica, the Black-faced eaters. Grassquit forages at two distinct and disjunct lev­ It is also possible that when foraging, S. insul­ els: either on the ground or from I m above ground aris perches on more slender stems, whether these to the canopy. Tn contrast, the Yellow-faced GTass­ are grasses and forbes, or branches of trees. Grey quit tends to forage between the ground and 1 m seedeaters will take insects, buds and fruit (Sick above ground; whilst it may be seen on the ground, I 993, Thomas 1996), but on each occasion it was it feeds by reaching up to the seeds of growing assumed that the species under observation was S. grasses, a foraging mode not seen in Black-faced intermedia although it could have been S. insul- Grassquit. Where the two are not sympatric, such 42 REST ALL as Panama and Costa Rica, the Yellow-faced Grass­ quite glossy (Belcher and Smooker 1937), perhaps quit forages freely on the ground (Wetmore et at. glossier than those of S. intermedia. 1984, Slud 1964) as does the Black-faced Grassquit Based on observations of captive males, the in Venezuela and Colombia (Ridgely and Tudor song of S. insularis is similar to that of S. inter­ 1989). media in that it consists of a set of several distinct 1l1e females of S. insularis are exceedingly phrases rapidly following each other. The notes difficult to identify. With so few specimens that can vary from chew and chirp to clear and mellifluous be regarded as S. insularis with certainty, consist­ trills and whistles. The sets are often of different ent distinguishing plumage characters have not lengths and seldom in the same sequence. In the been found. A preliminary statistical analysis sug­ case of S. insularis, the series always begins with gests tl1at bill size of female S. insularis is larger four to six sharp "bzzt" notes followed by usually than that of S. intermedia (Restall, unpubl. data). three "tew" or "chew" notes. Then follow in rapid On one occasion in the field we mist-netted only S. succession several different notes, each repeated insularis males; thus, the females caught at the five or six times. The longer series always ends with same time and place were tentatively assumed to be a set of loud, clear and musical canary-like notes S. insularis. The bills of these females were only "sweet sweet sweet sweet..." or "twee twee twee slightly smaller than those of the males, in contrast twee ... " with female S. intermedia which has on average a S. intermedia is often referred to as an accom­ larger bill than the male. plished mimic (e.g., Cherne 1916, Thomas 1996), Tl1e biology and behaviour of the two species incorporating into its repertoire various notes and are poorly documented, primarily because most noises from other sources, including, for example, observations were assumed to be of S. intermedia. even the calls of frogs and a squeaking gate. I have Nevertheless, r have deduced a few differences in not been able to detect this tendency in the few S. nest construction and egg colouration, based on insularis studied so far. the scant literature available (Cherne 1916, Belcher In conclusion, the consistent differences in andSmooker 1937, ffrench 1973, 1991 , Ferraro and plumage, bill colouration, morphology and perhaps Lentino I 992) and limited personal observations in behaviour between S. insularis and S. intermedia, the field. combined with their sympatric distribution, The typical cup-shaped nest of S. intermedia strongly suggest that they may be distinct, cryptic is made entirely of root fibres and fine tendrils and species (Paterson 1993) whose biology needs fur­ fibres. The similarly-shaped nest of S. insularis is ther study. I tentatively propose recognition of S. also made of root fibres and fine tendrils, but in insularis as a valid species. In view of the use of addition includes grasses. the name ' Ring-neck' on Trinidad (ffrench 1973, The eggs of the two species appear to differ 1991), 1 suggest using the English name of Ring­ primarily in ground colouration. The eggs of S. necked Seedeater and the Spanish name of Espi­ intermedia are variable, with a du11 white, greyish, guero Collarblanco buffy or creamy white ground colour, spotted and blotched with greys and browns, and overlaid with ACKNOWLEDGEMENTS irregularly distributed and much darker markings of rich brown. Based on a description of a nest in San 1 especially thank Clemencia Rodner and Juan, Trinidad, found on 14 July 1933, Belcher and Miguel Lentino, my colleagues at the Colecci6n Smooker (193 7) described the eggs of S. insularis Ornitol6gica Phelps, for their considerable and sig­ (attributed to S. plumbea colombiana, though nificant help and support in the production of this clearly referring to S. insularis) having a greenish­ paper. M. Isler most generously gave much time grey or greenish ground colour marked with and effort in constructively reviewing early drafts. blotches of greyish or greyish-brown, overlaid with T. Zoechner and J. C. Eitniear reviewed the final blotches of darker and richer browns, thickest draft. P. Sweet, C. Vogel and J. Weicker of the around the larger end. They are slightly glossy or American Museum ofNatural History, New York, Ring-necked Seedeater (Sporophila insularis) 43 were especially helpfu I in detailing the plumage and HERKLOTS, G. A. C. 1961 . The birds ofTrinidad and measurements of S. insularis specimens. I also Tobago. Collins, London. 287 pp. thank A. Pirie, Museum of Comparative Zoology, JUNGE, G. C. A. , AND G. F. MEES. 1961. The avifauna Harvard University, Cambridge, MA, and R. Panza, ofTrinidad and Tobago. Zool. Verhand. 37:1- Carnegie Museum of Natural History, Pittsburgh, 172. P A, for their generosity and willingness to help. MAYR, E. 1963. Animal species and evolution. Har­ The following museums kindly allowed me to study vard University Press, Cambridge, MA. 974 pp. specimens: U. S. National Museum of Natural MAYR, E. 1982. The growth of biological thought. History, Smithsonian Institution, Washington, DC.; Harvard University Press, Cambridge, MA. 974 Museum of Zoology, Louisiana State University, pp. LA; Natural History Museum, Tring, England; MEYER DE SCHAUENSEE, R. 1952. A review of the Museo de Historia Natural La Salle, Caracas; and genus Sporophila. Proc. A cad. Nat. Sci., Phila­ the Museo de Historia Natural de Ia Estacion Bio- delphia 104:153-196. 16gica, Rancho Grande, Maracay. PATERSON, H. E. H. 1993. Evolution and the recog­ nition co11cept of species. Johns Hopkins Uni­ LITERATURE CITED versity Press, Baltimore. 244 pp. PAYNTER, R. A., JR. (ed). 1970. Checklist of the BALDWIN, s. P., H. C, OBERHOLSER, AND L. G. birds of the World. Vol. 13. Harvard University WOR LEY. 1931. Measurements of birds. Sci. Press, Cambridge. 443 pp. Publ. Cleveland Mus. Nat. Hi st., Vol. IT, Contr. PEREZ, E. H. 1999. Dietary relationships among No. 17. granivorous doves in Venezuelan savannas. BELCHER, C.,AND G. D. SMOOKER. 1937. Birds of the Abstracts, pp. 115-116 . VI Neotropical Ornitho­ Colony of Trinidad and Tobago.-Part VI. Ibis logical Congress, Mexico,4 -10 October, 1999. 193 7:505-550. PULLIAM, R. 1969. The feeding ecology of Jamaican BIRD, J. R. 1983. Behavioral and ecological com­ grassland finches. Gosse Bird Club Broadsheet parisons of Lesser Antillean Bullfinches: a 12 :7-10. study of the evolution of sexual dimorphism RESTALL, R. L. 1995. Munias and mannikins. Pica and monomorphism. Unpubl. Ph.D. diss., Uni­ Press I Yale University Press, New Haven, CT. versity of Montana. 264 pp. BLONDEL, J., F. VUILLEUMIER, L. F. MARCUS, AND E. RIDGELY, R. S., AND G. TL:DOR. 1989. The birds of TEROUANNE. 1984. Is there ecomorphological South America. Vol. 1. The oscine passerines. convergence among Mediterranean bird com­ University of Texas Press, Austin, TX. 516 pp. munities of Chile, California and France? Evol. RIDGWAY, R. 1912. Color standards and color nom­ Bioi. 18:141-213. enclature. Published by the author, Washing­ CHERRIE, G. K. I 916. A contribution to the orni­ ton, DC. 48 pp. thology of the Orinoco Region. Mus. Brooklyn SICK, H. 1993. Birds in Brazil. Princeton University Tnst. Arts Sci.: Sci. Bull. 2:133-374. Press, Princeton, NJ. 703 pp. FERRARO, C., AND LENTINO, M . 1992. Venezuela­ SLUD, P. 1964. The birds of Costa Rica. Bull. Amer. paraiso de aves. Armitano, Caracas. 221 pp. Mus. Nat. Hist. 128:1 -430 pp. FFRENCH, R. 1973. A guide to the birds of Tri11idad SOKAL, R. R., AND F. J. ROHLF. 1981. Biometry. 2nd and Tobago. Harrawood Books, Newtown ed. W. H. Freeman and Company, New York. Square, P A. 470 pp. 859 pp. FFRENCH, R. I 99 I. A guide to the birds of Trinidad STILES, F. G. 1996. When black plus white equals and Tobago. 2nd ed. Cornell University Press, gray: the nature of variation in the Variable Ithaca, NY. 426 pp. Seedeater complex (Emberizinae: Sporophila). GILLIARD, T. 1946. New seedeaters from South Omitol. Neotrop. 7:75-107. America. Auk 63:570-574. THOMAS, B. T. 1996. Notes on the distribution, 44 REST ALL

body mass, foods and vocal mimicry of the 67719, 67722; Cafio Merejina, DeltaAmacuro: COP Gray Seedeater (Sporophila intermedia). Omi­ 64701; Curiapo, DeltaAmacuro: COP 50043; Mision tol. Neotrop. 7:165-169. Araguimujo, DeltaAmacuro: COP 48270; Guaniamo,

WETMORE, A. , R. F 0 p ASQUIER, AND S. OLSON. 1984. Bolivar: COP 26132; Caracara, Bolivar: COP 45800; The birds of the Republic of Panama, part 4. Los Caracas, Distrito Federal: COP 18225: Villa del Smithsonian Institution Press, Washington, Rosario, Zulia: COP 7113; Quebrada El Charal, DC. 670 pp. Aroa, Yaracuy: COP 77 418: San Vicente, Maturin, Monagas: COP 53923; PiritU, Portugueses: COP APPENDJX 80201 , 80202,80203,80208,80209, 80210; Guiria, Sucre: AMNH 514433. Museum specimens of S. insularis examined. COP = Colecci6n Omitol6gica Phelps, Caracas; TRINIDAD: Chaguaramas: AMNH514436; Caparo: AMNH = American Museum of Natural History, AMNH514427,514428,514429,514430, 514431; New York. Pointe Gourde: AMNH 514435; Leclet: AMNH 514433, 514434; Valencia: AMNH 514437; San VENEZUELA: Pedemales, Delta Amacuro: COP Fernando: AMNH59105;no Iocality:AMNH41265. 67720, 67721; Capure, Delta Amacuro: COP 67718, Pp. 45-53 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. 11, 2002.

ECOLOGICAL CHANGES AND THEIR IMP ACT ON AVIAN USE OF MARSHES IN CARONI SWAMP, TRINIDAD

GAIL C. CUFFY Department ofLife Sciences, University ofthe West Indies, St. Augustine, Trinidad and Tobago

ABSTRACT.-A vi an species were inventoried at four marsh sites at Caroni, Trinidad, as part of a baseline study assessing the current value of the marshes to birds. Data were sought in light of recent ecological changes to the area and a restoration project that sought to recreate former freshwater conditions within the area. Seventy-two species of birds were recorded. Comparison with earlier inventories revealed that about half of the previously recorded swamp species still occur in the marshes. Migrants comprised 30% of all marsh species. Restoration of the marshes involving the exclusion of seawater via impoundments will likely improve on avian species diversity and population sizes, and enhance the ecological value of the wetland habitat.

RESUMEN.-Se estudi6 las especies de aves presentes en cuatro pantanos de Caroni, Trinidad, como parte de un estudio basico para evaluar el actual valor de los pantanos para las aves. Se buscaron datos a la luz de cambios ecol6gicos recientes del area y un proyecto de restauraci6n cuyos fines fueron recrear las condiciones anteriores de agua dulce dentro del area. Se registraron 72 especies de aves. Una comparaci6n con inventarios del pasado revelaron que aproximadamente Ia mitad de las especies de pantano registradas previamente existen a(m en los pantanos. Las especies migratorias constituyen un 30% de las especies de pantano. La restauraci6n de los pantanos que involucre Ia exclusion de agua salada por medio de diques probablemente aumentaria Ia diversidad de aves de pantano y el tamaiio de poblaciones, y mejoraria el valor ecol6gico del habitat de humedales.

KEY WORDS.-birds, coastal management, Caroni Swamp, freshwater, habitat restoration, marshes, saltwater, Trinidad, waterbirds, wetlands

The Caroni Swamp (Fig. 1) is the largest wet­ these two habitats are the most significant to birds. land on the west coast of Trinidad and has long The Caroni Swamp has undergone extensive, an­ been recognized for its importance to birds. Bacon thropogenic ecological changes, particularly over (1970) recorded 13 8 species using the area, while the last 30-40 years, with major impacts on the ffrench ( 1977) recorded 157. A mosaic of habitats eastern marsh environments. This was thought to exists within the wetland, including herbaceous have consequently affected the overall value of the marsh and mangrove, as well as interfaces between wetland as an avian habitat. mangrove and marsh, marsh and swamp-forest, and Two main differences exist between the origi­ marsh and seacoast (Ramcharan and ffrench 1987). nal and current marsh environments: salinity and Mangroves, marshes and the interface between size. The first has had major implications for certain

45 46 CUFFY

\II

\II \II \II \II Mangrove \II \II Sedge Marsh \II Uriah Butler Highway 0 2.5

Km

FIG. J. Map ofCaroni Swamp, Trinidad, with study areas indicated by numbered circles.

wetland birds and the general marsh ecology. well-developed area of freshwater marsh known as Marsh salinity increased significantly owing to the the 'Reeds' (Bacon 1970). Resultant losses of fresh­ failed Cipriani Rice Scheme, which was initiated in water vegetation such as water lilies (Nymphaea the early 1920s with a view to using the swamp for ampla) and water hyacinths (Eichhornia cras­ rice cultivation (Bacon 1970). Adverse ecological sipes), used by many aquatic birds at the time, were changes did not occur until the 1960s and 1970s. heavy. The area was subsequently converted to a Improper maintenance of a main north-south em­ brackish marsh dominated mainly by sedges and bankment constmcted to exclude sea water from grasses (Bacon 1970). the swamp resulted in intrusion of saltwater into a A reduction in marsh size has accompanied the Marsh Avifauna ofCaroni Swamp, Trinidad 47 changes in salinity. Whereas previously the entire use of the mangroves (e.g., £french 1966), which is eastern third of the Caroni Swamp was herbaceous not surprising since mangrove stands now com­ freshwater marsh, encroachment of mangroves from prise a major portion of the swamp's area. Research the west, favored by the saline conditions, has on the marsh avifauna has been more limited. In an reduced the marshes to a thin border along the effort to assess the value of the marshes as an eastern margin. avian habitat with reference to a proposed resto­ Literature reporting changes in avian use of ration project aimed at recreating freshwater con­ the area following the failure of the rice scheme is ditions in the area, I undertook a general inves­ sparse and generally non-quantitative in nature. tigation into its seasonal use by birds (Cuffy 1999). However, it is known that when seawater was The species inventory presented here is derived effectively excluded from the area, there was heavy from this study, and is thought to have recorded use by a number of species. Belcher aud Smooker the majority of birds using the Caroni marshes. (1934) reported the nests of Yellow-hooded Black­ birds (see Table I for scientific names of birds) as METHODS numbering in the many hundreds in July 1930. Vari­ ous bitterns, Masked Ducks, Soras, Purple Galli­ Four sites within the Caroni marshes (Fig. 1) nules and Red-breasted Blackbirds also are said to were studied simultaneously over a period of 18 have flourished under the freshwater conditions months. All study areas were adjacent to the Uriah (Ramcharan et al. 1982). The then-abundant cover Butler Highway. Site I, or Cacandee, was located of water lilies and water hyacinths might have off Pierre Road and consisted of large stands of encouraged the breeding of the Masked Duck sedge marsh interspersed with patches of open (Herkl ots 1961 ). Scarlet Ibises were also reported as water, and was fringed by mangroves to the north­ feeding in the Reeds area, particularly during their west. Site 2, also known as 'Benson and Hedges' breeding season (Bacon 1970). owing to a nearby billboard, was a 300m wide area Effects on the avifauna subsequent to the of low sedge situated near a drainage channel of dete1iorati011 of the embankments include an east­ the Guyamare River. Site 3, also named '1 03 FM' ward shift in the feeding areas of Cattle Egrets owing to another adjacent advertisement, was an (Ramcharan et al. 1982), which forage exclusivelyin area of sedge marsh approximately 30m wide fring­ freshwater or terrestrial habitats (ffrench 1991 ). The ing the landward side of a 200m wide body of shal­ numbers of Purple Gallinules were reported as de­ low water. Site 4, adjacent to the Caroni Boat Dock, clining, attributable to intolerance of saltwater con­ lies immediately south of Drain 9 in the Caroni ditions (Ramcharan et al. 1982). Eichhornia sp., a Savannah lands. It consisted of an area 200m wide, prefen·ed food resource of this species ( ffrench divided by a footpath, giving way to open water 1991 ), was killed off by the intruding seawater bordered by low marsh, as well as scattered trees (Bacon 1970). Increasing salinities are also blamed and shrubs that may represent a former swamp­ for the failure of the Scarlet Ibis to breed locally forest stand (Bacon et al. 1997). since 1970. According to Bildstein (1990), adult On a single morning every fortnight, from birds feed in brackish areas, mainly on fiddler crabs January 1996 to June 1997, visits were made to all ( Uca sp.). However, inactive salt glands in juvenile sites in order to record all species seen as well as birds require that the young be fed on freshwater other data (Cuffy 1999). A total of 35 visits were prey(Bildstein 1990), which are locally scarce. Carib made to each site. Birds were identified with the aid Grackles, by contrast, reportedly responded favour­ of 7X35 binoculars and a spotting scope. The re­ ably to tl1e new conditions by establishing a large sultant inventory represents the combined records roosting site, shared with Yellow-hooded Black­ from all four sites. birds and Shiny Cowbirds, in young mangroves created by the saltwater intrusion (£french and RESULTS Manolis 1983). Several avian studies have reported on species Table 1 provides a list of species known to oc- 48 CUFFY

TABLE 1. Avian species recorded in Caroni Swamp, Trinidad, based on Bacon (1970) with later additions by ffrench (1977, indicated with *)and this study(**). Taxonomy is based on American Ornithologists' Union (1998) and ffrench (1991). Status is based on ffrench (I 977): R =resident; NV = northern visitor; SV =southern visitor; R +NV= species with both northem visitor and resident status. Frequency in marshes refers to frequency of field trips in which species was recorded (n = 35).

Frequency Frequency Species Status in marshes Species Status in marshes Least Grebe R W11ite Ibis sv Tachybaptus dominicus Eudocimus a/bus Pied-billed Grebe R 0.03 Scarlet Ibis R 0.71 Podylimbus podiceps Eudocimus ruber Brown Pelican R Glossy Ibis NV Pelecanus occidentalis Plegadis falcinellus Neotropic Connorant SV 0.37 Roseate Spoonbill sv Phalacrocorax brasilianus Ajaia ajaja Anhinga SV 0.03 Wood Stork sv Anhinga anhinga Mycteria americana Pinnated Bittern R Black Vulture R 0.29 Botaums pinna/us Coragyps atratus Least Bittern R 0.11 White-faced Whistling-Duck sv h:obrychus exilis Dendrocygna viduata Stripe-backed Bittem R lllack-bellied Whistling-Duck R 0.03 lwbrJ!chus involucris Dendrocygna autumnalis Rufescent Tiger-Heron R Fulvous Whistling-Duck R+SV 0.03 Tigrisoma lineatum Dendrocygna bico/or Great Blue Heron NV 0.11 Snow Goose* NV Ardea herodias Chen caerulescens CocoiHeron sv Comb Duck sv Ardea cocoi Sarkidirornis melanotos Great Egret R+NV 0.71 Muscovy Duck sv Ardea alba Cairina moschata Little Egret* E American Widgeon NV Egretta garzetta Anas americana Snowy Egret R+NV 0.60 Mallard NV Egretta thula Anas platyrhynchos Little Blue Heron R+NY 0.89 Blue-winged Teal NV Egret! a caerulea A nas discors Tricolored Heron R 0.77 Northern Shoveler* NV Egrelta tricolor Anas clypeata Cattle Egret R 0.71 White-cheeked Pintail R 0.14 Bubulcus ibis Anas bahamensis Green Heron NV 0.54 Ring-necked Duck NV Butorides virescens Alhya co/laris Striated Heron R+NV Lesser Scaup NV Butorides striatus Athya affinis Agami Heron sv Masked Duck R 0.03 Agami agami Nomonyx dominicus Black-crowned Night-Heron R 0.06 Osprey NV 0.77 Nycticorax nycticorax Pandion haliaetus Yellow-crowned Night-Heron R 0.31 Pearl Kite** R 0.03 Nyctanassa violacea Gampsonyx swainsonii Boat-billed Heron R White-tailed Kite SV Cochlearius cochlearius Elanus leucurus Marsh Avifauna of Caroni Swamp, Trinidad 49

TABLE 1 continued.

Frequency Frequency Species Status in marshes Species Status in marshes Snail Kite* sv Semipalrnated Plover NV 0.06 Rostrhamus sociabilis Charadrius semipalmatus Long-winged Harrier R Black-necked Stilt R 049 Circus buffoni Himantopus mexicanus Gray Hawk** R 0.09 Wattled Jacana R 0.97 As turin a nitida Jacmwjacana Common Black·I-Iawk R 040 Greater Yellowlegs NV 020 Buteogallus anthracinus Tringa melanoleuca Great Black-Hawk R 0.06 Lesser Yellowlegs NV 0.40 Buteogallus urubitinga Tringa flavipes Ornate Hawk-Eagle** R 0.03 Solitary Sandpiper NV Spizaetus omatus Tringa solitaria Yellow-headed Caracara R 0.03 Spotted Sandpiper NV 0.29 Milvago chimachima A ctitis macularia Merlin* NV 0.09 Whimbrel * NV 0.11 Falco columbarius Numenius phaeopus Aplomado Falcon** NV 0.03 Semipalmated Sandpiper NV Falco femora/is Calidris pusilla Peregrine Falcon* NV Western Sandpiper NV Falco peregrinus Calidris mauri Gray-breasted Crakc* R Least Sandpiper NV 0.06 Laterallus exilis Calidris minutilla Clapper Rail R 0.06 White-rurnped Sandpiper NV Rallus longirostris Calidris fuscicollis Rufous-necked Wood-Rail R Stilt Sandpiper NV A ram ides axillaris Calidris himmztopus Gray-necked Wood-Rail R Short-billed Dowitcher NV Arnmides cnjanea Limnodromus griseus Sora NV Gull-billed Tern NV Poruma carolinn Sterna nilotica Ash-throated Crake R Caspian Tern* NV Porzana alhicollis Stema caspia Yellow-breasted Crakc* R LeastTem NV 0.14 Porzana a/biventer Sterna anti/larum Spotted Rail R Yellow-billed Tern** sv 0.09 Pardira/Ius maculatus Stem a superciliaris Purple Gallinule R 0.34 Large-billed Tern sv 0.34 Porphynda martinica Phaetusa simplex Common Moorhen R 0.54 Black Skimmer sv 0.26 Gallinula choloropus Rhynchops niger Caribbean Coot* NV Pale-vented Pigeon R Fulica caribea Columba cayennensis Southern Lapwing R 0.17 Eared Dove R Vane/Jus chilensis Zenaida auriculata Black-bellied Plover NV Plain-breasted Ground-Dove* R 0.06 Pluvialis squatorola Columba minuta Lesser Golden Plover NV Ruddy Ground-Dove R 0.54 Pluvial is dominica Columbina talpacoti Collared Plover* R Green-mmped Parrotlet R Charadrius collaris Forpus passerinus 50 CUFFY

TABLE 1 continued.

Frequency Frequency Species Status in marshes Species Status in marshes Yellow-billed Cuckoo NY Crested Doradito* R Coccyzus americanus Pseudocolopteryx sclateri Mangrove Cuckoo R Forest Elacnia R Coccyzus minor Myiopagis gaimardii Dark-billed Cuckoo* R Northern Scrub-Flycatcher** R 0.03 Coccyzus melancoryphus Sublegatus arenarwn Little Cuckoo* R Yellow-breasted Flycatcher R Piaya minutn Tolmomyias jlavivemris Striped Cuckoo R 0.17 Pied Water-Tyrant R 0.83 Tapera naevia Fluvicola pica Greater Ani R White-headed Marsh Tyrant R 0.86 Crotoplzaga major Fluvicola leucocepha Ia Smooth-billed Ani R Swainson 's Flycatcher* sv Crotophaga ani Myiarchus swainsoni Bam Owl R 0.03 Brown-crested Flycatcher R Tyto alba Myiarchius tyrrmnulus Tropical Screech Owl R Great Kiskadee R 0.66 Otus choliba Pitangus sulphuratus Lesser Nighthawk R Tropical Kingbird R 0.51 Chordeiles acutipennis Tyrannus me/icholicus Nacunda Nighthawk R Gray Kingbird R Podager nacunda Tyrannus dominicensis White-tai led Nigh~ar R Fork-tailed Flycatcher SY 0.06 Caprimulgus cayennensis Tyrannus savana Common Po too R White-winged Becard R Nyctibius griseus Pachyramphus polychopterus Green-throated Mango R Golden-fronted Greenlet R Anthracothorax viridigula Hylophilus auralltiifrons White-tailed Go1denthroat R Rufous-browed Peppershrike R Polytmus guninumbi Cychlarhis gujanensis Belted Kingfisl1er NY White-winged Swallow* R Ceryle alcyon Tachycinetaalbiventer Amazon King lis her SV Blue-and-white Swallow SY 0.11 Chloroceryle amazon a Pygochelidon cyanoleuca Green Kingfisher R Bam Swallow NY Chloroceryle americana Hirundo rustica American Pygmy Kingfisher R Bare-eyed Robin R Chloroceryle aenea Turdus nudigenis Red-rumped Woodpecker R Tropical Mockingbird R 0.46 Veniliornis kirkii Mimus gilvus Pale-breasted Spinetail R Yellow Warbler NV 0.09 Synallaxis albescens Dendroica petechia Y cHow-chinned Spinetail R 0.97 B1ackpoll Warbler NY Certhiaxis cinnamomea Dendroicn striata Straight-billed Woodcreeper* R American Redstart NY Xiphorynchus piC!tS Setophaga nllicilla Black-crested Antshrikc R Prothonotary Warbler NV Sakesphorus canadensis Protonotaria citrea Silvered Antbird R Northern Waterthrush NV Sclateria naevia Seiurus noveboracensis Marsh Avifauna ofCaroni Swamp, Trinidad 51

TABLE I continued.

Frequency Frequency Species Status in marshes Species Status in marshes Masked Yellowthroat R Red-capped Cardinal R 0.17 Geothylpis aequinoctialis Paroaria gularis Bananaquit R Grayish Saltator R 0.06 Coereba jlaveola Saltntor coeru/escens llicolored Canehill R 0.03 Dickcissel NV Coniroslrum bicolor Spiza americana Blue-gray Tanager** R 0.09 Yellow-hooded 131ackbird R 0.94 Thraupis episcopus Agelaius icterocephalus P~lm Tanager** R 0.06 Red-breasted Blackbird R 0.54 Thraupis palma rum Sturnella militaris Blue-black Grassquit R 0.43 Carib Grackle R 0.86 Volminia jacarina Quiscalus /ugubris Lesson's Seed eater R Shiny Cowbird R 0.11 Sporophila bouvronides Molothrus bonariensis Ruddy-breasted Seedeatcr R Yell ow Oriole R 0.06 Sporophila minuta Icterocepha/us nigrogularis

cur in Caroni Swamp according to Bacon (1970), brackisl1 prey to which nestlings are intolerant is ffrench ( 1977) a11d this study, and the frequency of now available. field trips in whicl1 each species was recorded with­ Pearl Kite.-This resident, previously reported in marshes. Of 162 species recorded within Caroni as rare (ffrench 1990), has in recent times become Swamp, I recorded 72 in the marshes (Table I), in­ almost common. It was observed only once during dicating that at least 44.4% of the Caroni Swamp's a preliminary visit to site 2, before censussing for species utilise the marsh. In addition, several spe­ this study was formally begun. cies not recorded in either of the earlier studies Great Blue Heron.-This species was recorded were observed: the Ornate Hawk-Eagle, Merlin, twice, once on 10 January 1996 (12) and again on 21 Plain-breasted Ground-Dove, Blue-gray Tanager August 1996 (eight), both times only at Site 1. The and Palm Tanager. In terms of resident or migrant birds were feeding on exposed mudflats near the status, I recorded 46 residents, four northern visi­ mangroves. ffrench (1990) lists the species as a tors and six southern visitors. Four species had regular visitor to both Trinidad and Tobago in small both resident and northem migrant populations, numbers. It is occasionally hunted. while there was only a single species with both Black-bellied Whistling Duclc.-This species resident and southern visitor populations. Overall, was recorded only once, on 6 July 1996, when two migrant species accounted for 30% of the marsh birds were seen in flight at Site 4. The bird is a local avifauna. resident commonest during the wet season (ffrench Details for several noteworthy species, either 1990). rare visitors subject to hunting pressure, or of na­ Fulvous Whistling-Duck.-This species was tional importance, are given below. recorded only once, on 15 June 1997 at Site 2 (se­ Scarlet Ibis.-This species, while recorded at ven individuals in flight). This species is known as three of the four sites, was never present in the an occasional visitor, sometimes occurring in sig­ marshes in numbers greater than I 00 (27 April nificant numbers, and is known to breed in marshes 1996). Both adults and older juveniles were ob­ during the wet season (ffrench 1990), including ad­ served. The marshes are currently assumed to be of jacent rice fields (F.E. Hayes pers. comm.). value only to these later stages in the life cycle White-cheeked PintaiL-This species appeared rather than to the nestling stage, as only the at the end of the dry season of 1996, when it was 52 CUFFY recorded at Site 1 from May to July, with up to four marsh desirable both ecologically and economi­ on 25 May; on 9 June two were recorded at Site 3. cally. The Caroni marshes represent the last exist­ ffrench (1990) describes this bird as an uncommon ent part ofthe former Reeds area. Its restoration will resident. thus not only maintain the diversity of habitats Ornate Hawk-Eagle.-This species was record­ present in the swamp, but also preserve one of the ed only once, on 10 January 1996, with a single few remaining marsh habitats in Trinidad. adult seen perched in a tree at Site I. ffrench (1990) lists this bird as uncommon but widespread. ACKNOWLEDGEMENTS Aplomado FalcoJJ.-One was seen at Site 1 on 6 January 1997 (K. L. Bildstein). This bird is listed I thank P.R. Bacon, K. L. Bildstein and F. E. as a rare visitor to Trinidad savannas by ffrench Hayes for their invaluable assistance with this (1990). study, and the University of the West Indies for facilitating this research. DISCUSSION LITERATURE CITED Given that nearly half of the originally recorded avifauna still uses the marsh, in addition to several AMERICAN ORNITHOLOGISTS' UNION. 1998. Check­ rare species as well as previously unrecorded ones, list of North American Birds. 7th ed. American the Caroni marshes remain important to birds Ornithologists' Union, Washington D.C. 829 despite recent environmental changes. Species pp. diversity continues to range from true wetland BACON, P. R. 1970. The ecology of the Caroni types such as herons, ducks and gallinules to non Swamp, Trinidad. Central Statistical Office wetland-dependent passerines. Printing Unit, Port-of-Spain, Trinidad. 68 pp. The proposed restoration project, studied by BACON, P.R., V. BISSESSAR, AND G. CUFFY. 1997. the University of the West h1dies and the Wildlife Final repmt on wetland ecology. Study of the Section of the Forestry Division and funded by the feasibility of marsh restoration in Caroni Inter-American Development Bank, seeks to recre­ Swamp, Trinidad. Unpubl. report to the Inter­ ate the former Reeds area in the Caroni Swamp. By American Development Bank and the Wildlife reconstructing the deteriorated impoundments to Section, Forestry Division, Government of exclude seawater from the marshes and restore Trinidad and Tobago. freshwater conditions, avian use of the marsh may BELCHER, C. AND G. D. SMOOKER. 1934. Birds of the be enhanced since many waterbird species are less colony of Trinidad and Tobago-part VI. Ibis tolerant of saltwater than freshwater. Avifauna! 1937:504-550. diversi ty is usually greatest where mangroves and CUFFY, G. C. 1999. Seasonal use of a Neotropical freshwater marshes occur in association, than marsh by birds; Caroni, Trinidad. Unpubl. M. where mangroves occur alone (Ramcharan et at. Pl1il. thesis, University of the West Indies, St. 1982). Augustine, Trinidad. 166 pp . With regard to the Scarlet Ibis, a small breed­ HERKLOTS, G. C. A. 1961. The birds of the colony of ing population has apparently recolonised Caroni Trinidad and Tobago. Collins, London. 287 pp. Swamp in recent years (R. Neckles pers. comm.). BILDSTEIN, K. L. 1990. Status, conservation and With recreation of the Reeds area, regular breeding management of the Scarlet Ibis Eudocimus may be reestablished. ruber in the Caroni Swamp, Trinidad, West Benefits to the avifauna likely wi11 include an Indies. Bioi. Cons. 54:61-78. increase in both diversity and size of populations, FFRENCH, R. P. 1966. The utilization of mangroves as well as similar improvements in the availability of by birds in Trinidad. Ibis 108:423-424. prey species and vegetation. These, together \vith FFRENCH, R. P. 1977. Birds of the Caroni swamp and the regular breeding of the Scarlet Ibis and pos­ marshes. Living World (J. Field Nat. Club Trin. sibilities for ecotourism, make restoration of the Tob.) 1977-1978:42-44. Marsh Avifauna ofCaroni Swamp, Trinidad 53

FFRENCH, R. 1991. A guide to the birds of Trinidad 1982. Inventory of the living resources of and Tobago. 2nd ed. Cornell University Press, coastal wetlands in Trinidad and Tobago. In­ Ithaca, New York. 426 pp. stitute of Marine Affairs, Carenage, Trinidad. FFRENCH, R. P AND T. MANOLIS. 1983. Notes on RAMCHARAN, E. K. AND R. P. FFRENCH. 1987. The some birds of Trinidad Wetlands. Living status and distribution of wetland-dependent World (J. Trin. Tob. Field Nat. Club) 1983- birds in Trinidad. Living World (J. Trin. Tob. 1984:29-31. Field Nat. Club) 1987-1988:36-40. RAMCI-IARAN, E. K., G. DE SOUZA AND R. P FFRENCH. Pp. 54-61 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds .). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. 11 , 2002.

AVIFAUNA OF A 'RECLAIMED' WETLAND: TRINIDAD'S LAVENTILLE MARSH IN THE 1960S

MICHAEL GOCHFELD Environmental and Occupational Health Sciences Institute, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA

ABSTRACT.- Trinidad has several important wetland habitats that are threatened by human activities. However, there are few published quantitative studies on the avifauna of Trinidad wetlands. I studied the avifauna ofLaventille Marsh, an impounded wetland bordering the Caroni River, Trinidad, during February-May 1965, and compiled records from earlier workers. Data are summarised on the occurrence of 125 bird species from the marsh. Although this particular wetland has been destroyed, the information on its rich avifauna should support efforts to protect other comparable wetlands on Trinidad and in the Neotropics.

RESUMEN.- Trinidad tiene algunos humedales importantes que est

KEYWORDS.-avifauna, freshwater, Laventille Marsh, Trinidad, waterbirds, wetlands

Although tropical conservation focusses most Virus Laboratory (TRVL). While there I had the of its attention on the dwindling rain forests, the privilege of exploring several habitats under the plight of threatened wetlands must not be over­ tutelage of the late C. Brooke Wmth, M.D. Wortll looked. Draining of wetlands and rice culture are showed me the Laventille Marsh, where TRVL had among the greatest threats to freshwater marshes, conducted virus studies several years earlier. I had whereas aquaculture threatens coastal marshes and the opportunity to study the avifauna of the Laven­ mangrove swamps. Trinidad has several important tille Marsh and to add in a small way to the know­ wetland habitat>:. many of wl1ich are threatened by ledge of the Trinidad avifauna. The occurrence of one human activity or a11other (James 1990). These several rare or hitherto unlmown species including wetlands provide an important habitat for birds Common Yellowthroat(Geothylpis trichas), Glossy (Ramcharan and ffrench 1987), yet more intensive Ibis (Plegadis falcinellus), Ruff (Philomachus pug­ studies are needed on the avifaunas of each wet­ nax), and Yellow-breasted Crake (Porzana flavi­ land. venter) have been repmted previously (Gochfeld From February to May 1965, I was stationed at 1973a). This paper documents the richness of the the Rockefeller Foundation's Trinidad Regional avifauna of the Laventille Marsh circa 1965. AI-

54 Avifauna ofLaventille Marsh, Trinidad 55

tl1reemain impoundments. From the south end ofEl Socorro Road, the marsh extended more than I km west along the Caroni River, as well as eastward for about 1 km. Churchill· Roonvelt Highway Land reclamation from the Caroni Swamp be­ gan in the early 1920s with construction of a long ~~ I~ dike at the western edge of the mangroves (ffrench

Ctrt'dJJi 1985). Freshwater marshland gradually was drained SwnJIIP and planted. During the 1930s the Laventille Marsh '"" \ area was apparently a brackish marsh supporting a rich growth of sedges (Cyperaceae), drained by the FIG. I. Map illustrating the location of Laventille slow-flowingCaroni River. Shmtlyafter World War Marsh, Trinidad. II, the government accelerated land reclamation in tl1is area. A series of dams and dikes was built to ' exclude the brackish water of the Caroni Swamp from the marsh and to reclaim the resulting savan­ Impoundment 3 Impoundment 2 l nah for agriculture. In the late I 950s, however, the A I dikes began to leak significantly. The impound­ ments became brackish, and by about 1962 were unsuitable for agriculture. No crops had been plant­ ed in the area during the four years prior to my 1965 visit. Throughout the 1960s the marsh served as a haven for aquatic birds and was a regular stop on any birdwatching itinerary.

CarcHli Ri t'er Description.-The three major impoundments (Fig. 2) were separated from each other and from FIG. 2. Map of Laventille Marsh. the Caroni River by broad dikes, bordered by ca­ nals up to 8 m across and up to 1 m deep. Tn early February the impoundments still held water, al­ though the prime avian habitat in the Laventille ta1ough by early May much of the marsh was dry. Marsh has been destroyed, the infonnation pre­ The main vegetation in the impoundments sented here is offered in l10pe of supporting efforts included rusl1es (Cyperaceae, mainly Cyperus ar­ to protect other comparable wetlands in Trinidad ticulatus and Eleocharis mutata) and grasses (par­ and elsewhere in the Neotropics. ticularly bamboo grass, Paspalum fasciculatum and Bracharis mutica). The large emergent arum, STUDY AREA J.1ontrichardia arborescens, grew more than 2 m tall along the edges of some canals. A papyrus-like History.- The Laventille Marsh was located on emergent, Mariscus ferax, occuned in some of the the nmtheastern edge of the Cm·oni Swamp, along ditches, growing up to 60 em tall. The dike along the north bank of the Caroni River (Fig. 1). It was in tl1e Caroni River was lined with Swamp Immortelle an area that formerly had been called the Bordenal (E1ythrina sp.) and planted Coconut Palms (Cocos Savmmah. In the I 930s, Belcher and Smooker ( 1934, nucifera). There were also dense thickets of spiny 1935, 1936a, b, l937a, b) conducted extensive stud­ palms (Bactris sp.). ies of Trinidadian birds, mainly on 'the Nelson Impoundment 1 was bordered on the west by Estate', which was close to and may have included tl1e continuation of the El Soccoro Road. I visited it part of the Laventille Marsh. The marsh was lo­ in February and early March, but only briefly there­ cated only about 6 km from downtown Port of after, since most of the bird activity typically was in Spain. Three access roads divided the marsh into impoundment 2. I did not map this area. ~------

56 GOCHFELD

The middle impoundment (impoundment 2, ca. occasions I saw people patching the dikes, using 40 ha) included a group of four small rectangular stones hauled from farther inland and mud taken pools (area 2a of 1.6 ha). Vegetation included tloat­ from the marsh. One afternoon I observed a group iug plants such as Ipomea aquatica, Water Hya­ of men working with shovels and pails to widen cinth (Eichornia crassipes) and Water Lily (Nym­ and deepeu one of the canals along the road. phaea ampla). I studied these four pools inten­ Small fish and shrimp abounded in the ditches sively. 1l1ey retaiued water throughout the study, and canals. Adults and children used a variety of although as the dry season progressed, some parts netting techniques. The use of with cast-nets and became exposed mudflats. seines was quite popular. People snared shrimps Also in impoundment 2 was area 2b, about 305 with nooses fashioned from long blades of grass. m l011g by 110 m wide (ca. 3.3 ha), transected On one occasion I saw a finch trapper (an illegal lengthwise by a series of 18 parallel dikes, each activity) trying to catch seedeater, using a three­ about 2 m wide and separated by ditches, most of cell treadle-trap, with a male Ruddy-breasted Seed­ which were about 2 m wide. In February the water eater (Sporophila minuta) in the middle cell. in the ditches was 15 to 80 em deep, but by late Rainjall.-Based on 31 years of data (Smith April many of the ditches were dry, although some 1955), the mean monthly rainfall (em) measured at ditches still held up to 40 em of water. The dikes the agricultural station in St. Augustine (6.2 km were covered mainly by Cyperus, which in some from the marsh) was: January, 7.6; February, 4.5; places grew up to 2 m tall, while the ditches con­ March, 3.4; April, 4.9. By comparison the data for tained sparser growths of Cyperus up to 60 em tall. 1965 were January, 10.6; February, 4.8; March, 1.0; Two of the dikes closest to the river had been April, 2.1 (T. H. G. Aitken pers. comm). Thus, rain­ bumed and were covered only with short stubble. fall was slightly above normal during January and Impoundment 3 ( 44 ha) extended about 550 m February 1965, and far below normal during March westward along the Caroni River to a broad canal. and ApriL Aliliough drier than average, 1965 could There was a trail along the river which extended not be considered a drought year when its rainfall about 300m farther along the canal. I regularly used data are compared to the 1.7 em of rain that fell in this trail to survey the canal along the eastern edge February-March 1962. of this impoundment, and scanned by telescope the larger ditches tlmt extended into the impoundment. METHODS On 5 May I waded into this area impeded by 2-m­ high sedges and mud. Inside Tfound a mudflat sur­ I visited the Laventille Marsh on 16 occasions rounded by tall reeds. during the 1965 dry season from 17 February to 6 Laventille Marsl1 was a highly disturbed area, May. Most of my visits were in the early morning, representing an artificial assemblage of plants that but some were at other times and three at night. I did not fit comfortably into any of the vegetation covered the western part of impoundment 1 and the associations described by Beard (1946:128), who eastern part of impoundment 3 were covered only stated, "the herbaceous section of the Caroni three times. On most visits I covered most of Swamp consists of small sedges, but this has suf­ impoundment 2 and the western side of impound­ fered from attempts to reclaim the swamp, from rice ment 3. Areas 2a, 2b and the western border of 3 growing, and from fire, and is almost certainly not were studied intensively to examine the habitat pre­ the original vegetation." ferences of marsh birds. Other visits were very brief Land use.-A village was located about 400 m or occurred at night, and did not include bird lists. nmih of the study area. On each visit I saw people These include a brief visit on 30 April to collect in the marsh. They engaged in a variety of pursuits, plants. including hunting (once), fishing, coconut harvest­ In addition to my own sightings, I report re­ ing, pasturing of cattle (every visit), cutting grass, cords from C. Brooke Worth, who visited the marsh loafing and birdwatching. Coconuts were harvest­ 18 times between 1961 and 1964 (including times of ed, mainly for household consumption. On several the year when I was not present), and observations Avifauna ofLaventille Marsh, Trinidad 57 from three visits by Guy Tudor from 7-11 April preservation of tracts of sufficient size to minimise 1967. I also summarise the bird-netting results of the impact of human activities along their edges. TRVL, conducted primarily for surveillance for Many of the species at Laventille Marsh were Eastern Equine Encephalitis virus activities. Netting apparently tolerant of some multiple uses, such as took place from 15 October 1959 to January I 960 pasturing and fishing. On the other hand, a number and from November 1960 to 4 January I 96 I. of small rails such as Ash-throated Crake (Porzana albicollis) and Gray-breasted Crake (Laterallus RESULTS AND DISCUSSION exilis) reported by Belcher and Smooker (1935) could not be found at Laventille in 1965. There are Despite its relatively small size, the Laventille no recent Trinidad records for the former (ffrench Marsh was rich in bird diversity. At least 125 spe­ 1991), and Lateral/us crakes are easily overlooked cies of birds had been recorded from the marsh and seldom reported. However, they have charac­ through 1967 (Table I), though other birders have teristic vocalizations and I did not hear rail calls undoubtedly found additional species there. Sev­ which remained unidentified. eral of these were either new for the country, had Ecotourism is increasingly emphasised as a been recorded only a few times previously, or were way to provide economic incentives for protecting secretive species whose natural history was further habitats (Burger 2000). The opportunity to exploit documented (Gochfeld 1972, I 973a). A total ofl58 ecotourism as a way to encourage preservation of individuals of 36 species was netted by the TRVL, wetlands such as Laventille Marsh, should be including five species not subsequently recorded explored. A!though birdwatchers regularly hired from the marsh (Table 1; see Appendix). There was young boys for a few coins to wade through the a paucity of reports from summer months when a marsh and flush up birds so they could be seen and number of summer visitor species such as the Ro­ ' counted', this is not a sufficient nor dependable seate Spoonbill (Ajaja ajaia) might have occurred. source of income for a community. Ecotourism can During the 1965 dry season, virtually no nest­ also have negative effects from direct disturbance ing activity was observed in the Laventille Marsh, by frequent visitors (Burger et al. 1995). ffrench although I found birds nesting in other Trinidad (1985) suggested that frequent visits by noisy habitats. This lack of dry season nesting was also boatloads of tourists may have discouraged the reported by Snow and Snow (1964), who empha­ Scarlet Ibis from breeding in Trinidad. sized both the proximate and ultimate influence of Population growth, urbanisation and the rainfall on breeding seasons. spread of agriculture has had widespread and ser­ This paper is one of only a few providing ious impacts on the Trinidadian landscape (Fona­ quantitative data on the occurrence of birds in a roff1974, ffrench 1985). I wrote a bird-finding article specific wetland of Trinidad. Other such studies in­ on Laventille Marsh for Birding (Gochfeld 1973b ), clude those of Cuffy (2002) for the avifauna of the but several subsequent visitors who followed my Caroni marshes and White (2000) for the avifauna instructions in the 1970s told me that the Laventille of the Port of Spain Sewage Ponds. Such infor­ Marsh had been mostly destroyed. What was left mation is applicable to a wider range of similar hab­ was heavily disturbed and the most interesting itats in Trinidad. Searching for rails and small bit­ birds could no longer be found. Those interested in terns requires a special effort and a willingness to preserving biodiversity find such losses tragic. wade through uncharted, mucky waters. Although Fonaroff (1974) expressed guarded optimism that I enjoyed an occasional muckwalk, the parallel many species of land birds could adapt to suburban dikes at Laventille Marsh afforded the opportunity gardens and that planning could preserve their to criss-cross one of the impoundments while re­ populations in altered habitats. Waterbirds are maining high (improving visibility) and dry. This much more demanding, however, and require pre­ facilitated repeated and systematic surveying ofthe servation of adequate-sized wetland habitats. marsh. Moreover, the differential distribution of the birds A number of avian marsh specialists require in the Laventille Marsh illustrates that even within 58 GOCHFELD

TABLE I. Summary of bird records from Laventille Marsh, Trinidad. Taxonomy is based on American Ornithologists' Union (1998) and ffrench(l991). UnderTRVL(TrinidadRegional Virus Laboratory), the first number indicates the number of birds netted and the second number the number of dates netted. Species observed by Worth are indicated with an 'X'. The number of days observed is given under Tudor (up to three) and Gochfeld (up to 16). Under Gochfeld, the maximum number of individuals recorded in a day and range of dates are given.

TRVL Worth Tudor Gochfeld, 1965 Species 1959-61 1961-64 1967 Days Max Range of dates Pied-billed Grebe (Podilymbus podiceps) Anhinga (Anl1ina anhinga) 7 Apr Magnificent Frigatebird (Fregata magnificens) 20 Mar Great Blue Heron (Ardea herodias) 17 Feb Cocoi Heron (Ardea cocoi) 17 Feb Great Egret (Egretta alba) Snowy Egret (Egretta !hula) I 9 70 7 Mar-6 May Little Blue Heron (Egretta cerulea) X 3 16 30 17 Feb-6 May Tricolored Heron (Egretta tricolor) X 2 15 45 17 Feb-6 May Striated Heron (Butorides striatus) X 3 16 40 17 Feb-6May Green Heron (Butorides virescens) 1 25 Feb Chestnut-bellied Heron (Agmnia aganu) X Cattle Egret (Bub ulcus ibis) X 3 9 210 17 Feb-22 May Black-crowned Night Heron (Nycticora.x: nycticora.x) X Stripe-backed Bittern (Jxobrychus involucris) X 3 12 22 7 Mar-6 May Least Bitten1 (lxobryclws exilis) X 10 5 25 Feb-6 May Pinnated Bittern (Botaurus pinnatus) 3 l l6Mar Scarlet This (Eudocimus ruber) X 2 I 3 Mar30 Glossy Ibis (Plegadis fa/cine/Jus) I 2 3 24 Apr-6 May Blue-winged Teal {Anas discors) 2 2 7 Mar Masked Duck (Oxyura dominica) 2 2 7 Apr-24 Apr Black Vulture (Coragyps alratus) X 3 7 4 6 Mar-6 May Turkey Vulture (Cathartes aura) 3 Snail Kite (Rostrhamus sociabilis) X? Common Black-Hawk (Buteogallus anthracinus) X 4 6Mar Long-winged Harrier (Circus buffom) X 4 20 Mar-24 Apr Osprey (Pam/ion halieatus) 3 6 4 6Mar-6May Peregrine falcon (Falco peregrinus) l 2 30 Mar Limpkin (Ammus guarauna) 3 2 6 Mar-5 May Clapper Rail (Rail us longirostris) 7 2 17 Feb Spotted Rail (Rallus macula/us) Ill X 2 7 2 16 Mar-6 May Gray-necked Wood-Rail (Aramides cajanea) 1 1 5May Sora (Porzmza carolina) X I 10 30 17 Feb-24 Apr Yellow-breasted Crake (Porzanajlaviventer) l 9 6 20 Mar-6 May Common Moorhen (Gallinula chloropus) X 3 16 30 17Feb-6 May Purple Gallinule (Porphyrula martinica) X 2 8 5 17 Feb-10 Apr Wattled .Tacana (Jacanajacana) X 3 16 70 17 Feb-6 May Solitary Sandpiper (Tringa solitaria) X 3 8 3 15 Feb-6 May Lesser Y ellowlegs (Tringa jlavipes) X 2 II 55 6 Mar-6 May Greater Yellow legs (Tringa melanoleucos) X 2 3 16 24 Apr-6 May Spotted Sandpiper (Actitis macularia) X 2 15 5 25 Feb-6 May White-rumped Sandpiper (Calit/risfuscicollis) 2 10 5 May-6 May Least Sandpiper (Calidris minutilla) X 2 6 16 6 Mar-6May Pectoral Sandpiper (Calidris melanotus) X 2 5 May Avifauna ofLaventille Marsh, Trinidad 59

TABLE l continued.

TRVL Worth Tudor Gochfeld, 1965 Species 1959-61 1961-64 1967 Days Max Range of dates Semipalmated Sandpiper (Calidris pusilla) 5 20 13 Apr-6 May Ruff (Philomachus pugnax) 5 May Common Snipe (Gallinago gallinago) X 11 4 17 Feb-5 May Large-billed Tern (Phaetusa simplex) 24 Apr Rock Dove (Columba Iivia) 3 4 7 Mar-5 May Pale-vented Pigeon (Columba cayennensis) X 6 3 17 Feb-6 May Plain-breasted Ground Dove (Columbina minuta) Ruddy Ground Dove (Columbina talpcoli) 14/8 X 3 15 50 17 Feb-6 May White-tipped Dove (Leptotila verreauxi) X 2 8 4 25 Feb-6 May Green-rumped Parrotlet (Forpus passerina) X 2 10 14 25 Feb-6 May Little Cuckoo (Piaya minuta) Greater Ani (Crotophaga major) X 6 5 17 Feb-6 May Smooth-billed Ani (Crotophaga ani) 2/2 X 3 14 30 17 Feb-6 May Striped Cuckoo (Tapera naevia) X 7 1 7 Mar-6May Common Potoo (Nyctibius griseus) 6May Pauraque (Nyctidromus albicollis) 2 6 May Short-tailed Nighthawk (Lurocalis semicollaris) I 6May Chestnut-collared Swift (Cypseloides 1-uti/us) 2 5 30 Mar-13 Apr Gray-rumped Swift (Chaetura cinereiventris) 2 50 6Mar Short-tailed Swift (Chaetura brachyura) X 2 9 100 6 Mar-6 May Lesser Swallow-tailed Swift (Panyptila cayennensis) - 6 30Mar Fork-tailed Palm Swift (Reinarda squamata) 13 Apr Green-throated Mango (Anthracothorax viridigula) X 6 4 17 Feb-! 0 Apr Black-throated Mango (Anthracothorax nigricollis) 2 2 Feb 17 unidentified mango (Anthracothorax sp.) 2 3 17 Feb-10 Apr Ruby-Topaz Hummingbird (Chrysolampis mosquitus) 3 2 17 Feb-13 Apr Blue-tailed Emerald (Chlorostilbon mellisugus) 2 2 25 Feb White-tailed Goldenthroat (Po/ytmus guainumbi)s 2/2 2 7 Mar White-chested Emerald (Amazilia chionopectus) I Copper-mmped Hummingbird (Amazilia tobaci) 4/2 4 4 17 Feb-6 May Ringed Kingfisher (Ceryle torquata) 1 I 16Mar Green J(jngfisher (Chloroceryle americana) 3 16 Mar-10 Apr Pygmy Kingfisher (Chlorocelyle aenea) X Red-rumped Woodpecker ( Veniliornis kirkii) Yellow-throated Spinetail (Certhia.xis cinnamomea) 212 X 3 16 35 17 Feb-6 May Black-crested Antshrike (Sakesphorus canadensis) 3/3 X 2 5 10 17 Feb-10 Apr Barred Antshrike (Thamnophilus doliatus) 5/4 X 2 ll 6 17 Feb-6 May Pied Water-Tyrant (Fluvicola pica) 1117 X 3 16 30 17 Feb-6 May White-headed Marsh-Tyrant (Arundinicola Ieucocephala) X 2 15 2 17 Feb-6 May Fork-tailed Flycathcer (Tyrannus savana) X 4 7 7 Apr-5 May Tropical Kingbird (Tyrannus melancholicus) X 2 13 6 17 Feb-6 May Gray J(jngbird (Tyrannus dominicensis) X 7 6 17 Feb-7 Apr Great Kiskadee.(Pitangus sulphuratus) X 3 6 4 25 Feb-6 May Brown-crested Flycatcher (Myiarchus tyrannulus) X 24 Apr Dusky-capped Flycatcher (Myiarchus tuberculifer) Tropical Pewee (Conlopus cinereus) X Bran-colored Flycatcher (Myioplwbus fascia/us) ------·-----·------··· .. -·-·· ----·

60 GOCHFELD

TABLE 1 continued.

TRVL Worth Tudor Gochfeld, 1965 Species 1959-61 1961-64 1967 Days Max Range of dates Yellow-breasted Flycatcher (Tolmomyias flaviventris) X X Y cllow-bellied Elaenia (Eiaenia jlavigaster) 515 X 2 12 5 17 Feb-6 May Lesser Elaenia (Elaenia chiriquensis) Forest Elaenia (Myiopagis gaimardii) 2 7 Apr Scntb Flycatcher (Sublegatus modestus) 2 5 2 6 Mar-10 Apr Southern Beardless Flycatcher (Camptostoma obsoletum) 2 10 Apr Gray-breasted Martin (Progne chalybea) 5 15 6 Mar-? Southern Rough-winged Swallow (Stelgidopte1yx ruficoflis) 2 30 Mar-l 0 Apr Bank Swallow (Riparia riparia) 2 2 30 Mar-24 Apr Bam Swallow (Hirundo rustica) X 2 4 26 7 Apr-6 May House Wren (Troglodytes aedon) X 10 7 25 Feb-6 May Tropical Mockingbird (Mimus gilvus) X 2 ll 3 25 Feb-5 May Bare-eyed Timtsh (Turdus nudigenis) 1517 X 3 16 Mar-l 0 Apr Rufous-browed Peppershrike (Cychlaris gujanensis) X 3 2 6 Mar-? Shiny Cowbird (Molothrus bonariensis) 2/1 X 7 2 7 Mar-? Carib Grackle (Quiscalus lugubris) 21 /5 X 3 15 200 17 Feb-? Yellow-hooded Blackbird (Agefaius icterocephafus) 914 X 2 13 200 17 Feb-? Yellow Oriole (Icterus nigrogularis) X 3 8 6 17 Feb-5 May Red-breasted Blackbird (Leistes militaris) X I l 2 7 Apr Yellow Warbler (Dendroica petechia) 4/3 X I 6 4 17 Feb-? Northern Waterthntsh (Seiurus noveboracensis) 713 X 2 II 8 25 Feb-May 5 Northern Yellowtlrroat (Geothylpis trichas) I 6Mar Masked Y ellowthroat ( Geothylpis aequinoctialis) X 2 10 4 17 Feb-May 5 American Redstart (Setophaga ruticilta) 212 Bananaquit ( Coereba jlaveola) 11/8 X 3 8 6 17 Feb-13 Apr Blue-gray Tanager (Thraupis virens) X 2 6 20 17 Feb 17-13 Apr Palm Tanager (Thraupis palmarum) X 3 I I 60 17 Feb-13 Apr Silver-beaked Tanager (Ramplwcelus carbo) 10Apr Red-crowned Ant Tanager (Habia rubica) X White-lined Tanager (Tachyphonus rufus) Grayish Saltator (Saltator coerulescens) 2/2 X 6 4 17 Feb-10 Apr Dickcissel (Spiza americana) 2 l 30 Mar-13 Apr Blue-black Grassquit ( Volatinia jacm-ina) 8/3 X 3 13 20 17 Feb-6 May Gray Seedeater (Sporophila intermedia) 7/6 X 1 10 7 Apr Ruddy-breasted Seed eater (Sporophila minuta) 6/5 X 2 14 12 25 Feb-6 May

marshlands there should be a mosmc of habitat and recounting his experiences there. R. and M. types including varying water depths and vege- ffrench introduced me to several interesting areas tation. on Trinidad and were good friends duting my stay. They visited Laventille Marsh with me twice to see ACKNOWLEDGEMENTS some of the interesting birds I had found there. Many other observers including R. W . Dickerman, I am particularly indebted to the late C . B. R. Gochfeld and M. Kleinbaum accompanied me in Worth, M.D., for showing me the Laventille Marsh the field. I benefitted greatly from information Avifauna ofLaventille Marsh, Trinidad 61

impmted by Trinidadian bird guide, L. Calderon. servation. Sci. Total Environ. 249:39-49. Friends F. Bader, T. Davis, L. Morgan and G. BURGER, J., M. GOCHFELD, AND L. NILES 1995. Eco­ Tudor, as well as B. Worth allowed me to incor­ tourism and birds in coastal New Jersey: con­ porate their field notes. B. Kalloo of the University trasting responses of birds, tourists, and man­ of the West Indies Herbarium identified the plants. agers. Environ. Conserv. 22:56-64. W. Old ofthe American Museum ofNatural History CUFFY, G. C. 2002. Ecological changes and their identified the pomatid snails. C. Sibley provided impact on avian use of marshes in Caroni access to the Rasool collection at Yale. L. Spence, Swamp, Trinidad. Pp. 45-53 in Studies in director ofTRVL, showed great forbearance when T1inidad and Tobago ornithology honouring it became apparent that I was more interested in the Richard ffrench (F. E. Hayes and S. A. Temple, epizootiology of viral diseases than in the basic eds.). Dept. Life Sci., Univ. West Indies, St. virology. Other staffmembers ofTRVL, particularly Augustine, Occ. Pap. 11. T. H. G. Aitken were also very helpful. My experi­ FFRENCH, R. P. 1985. Changes in the avifauna of ence was enriched by the many local Trinidadians Trinidad. Ornithol. Monogr. 36:986-991. l met in the marsh, who recounted to me historical FFRENCH, R. 1991. A guide to the birds of Trinidad information and shared with me their interesting and Tobago. 2nd ed. Cornell University Press, natural history lore. P.R. Bacon, G. C. Cuffy and W. Ithaca, NY. 426 pp. L. Murphy provided helpful comments on the man­ FONAROFF, L. S. 1974. Urbanization, birds, and uscript J. Humphries created the maps. ecological change in northwestern Trinidad. Bioi. Conserv. 6:258-262. LITERATURE CITED GOCllFELD, M. 1972. Observations on the status, ecology and behavior of Soras wintering in AMERICAN ORNITHOLOGISTS' UNION. 1983. Check­ Triuidad, West Indies. Wilson Bull. 84:200-201. list ofN orth American Birds. American Orni th­ GOCHFELD, M. 1973a. Observations on new or ologists' Union: Washington D.C. 829 pp. unusual birds from Trinidad, West Indies, and BEARD, J. S. 1946. The natural vegetation of comments on the genus Plegadis in Vene­ Trinidad. Oxford For. Mem. 20:1-152. zuela. Condor 75:474-478. BELCHER, C., AND G. D. SMOOK.ER. 1934. Birds ofthe GOCHFELD, M. 1973b. Birding insert: LaventiHe Colony ofTrinidad and Tobago. Ibis 1934:572- Marsh. Birding 5:105-106. 595. JAMES, C. 1990. Wetlands management in Trinidad BELCHER, C., AND G. D. SMOOKER. 1935. Birds of the and Tobago. Ministry of the Environment and Colony of Yrinidad and Tobago.-Part H. Ibis National Service, Port of Spain. 35 pp. 1935:279-297. RAMCHARAN, E. K., AND R. P. FFRENCH. 1987. The BELCHER, C., AND G. D. SMOOKER. 1936a. Birds of status and distribution of wetland-dependent the Colony of Trinidad and Tobago.-Pa1t III. birds in T1inidad. Living World (J. Trin. Tob. Ibis 1936:1-35. Field Nat. Club) 1987-1988:36-40. BELCHER, C., AND G. D. SMOOKER. 1936b. Birds of SMITH, G.W. 1955. Rainfall reliability in Trinidad. the Colony of Trinidad and Tobago.-Part IV. Government Printing Office, Port of Spain. Ibis 1936:792-813. SNOW, D.W., AND B.K. SNOW. 1964. Breeding sea­ BELCHER, C., AI\ID G. D. SMOOKER. 1937a. Birds of sons and annual cycles of Trinidad land birds. the Colony of Trinidad and Tobago.-Part V. Zoologica 49:1-39. Ibis 1937:225-249. WHITE, G. 2000. Abundance and seasonal mi­ BELCHER, C., AND G. D. SMOOKER. 1937b. Birds of gration of birds at the Port of Spain Sewage the Colony of Trinidad and Tobago.-Part VI. Ponds. Living World (J. Trin. Tob. Field Nat. This 1937:505-550. Club) 1999-2000:20-26. BURGER, J. 2000. La11dscapes, tourism and con- Pp. 62-85 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. ll, 2002.

AVIFAUNA OF THE 'DRAGON'S TEETH': THE BOCAS ISLANDS, NORTHERN GULF OF PARIA, BETWEEN VENEZUELA AND TRINIDAD

FLOYD E. HAYES 1 AND lSHMAELANGELO SAMAD2 'Department ofLife Sciences, University of the West Indies, St. Augustine, Trinidad and Tobago and Department ofBiology, Caribbean Union College, P. 0. Box 175, Port of Spain, Trinidad and Tobago 2El Tucuche Hiking Lodge and Nature Retreat, Loango Village, Maracas, Trinidad and Tobago

ABSTRACT.-Situated in the northern Gulf of Paria, which separates Trinidad from the South American continent, the Bocas Islands comprise five major islands (up to 4.54 2 2 km ), ten minor islands (up to 0.08 km ) and many tiny islets. The predominant climax vegetation of the relatively arid islands includes littoral woodland and deciduous seasm1al forest on soils derived from sedimentary rocks. Data are provided on the abundance of 135 species of birds on the major islands based on general observations, point counts and mist-netting (three islands only). Only 31 species have been recorded on the minor islands. Of the 135 species, at least 34 have been confinned breeding, another 39 presumably breed, 32 likely represent non-breeding but locally resident (Venezuela or Trinidad) visitors, 25 are Nearctic migrants, two are Neotropical migrants, two are introduced visitors and one is extirpated (an additional ten are regarded as hypothetical). Seabirds and coastal waterbirds are scarce, presumably due to inadequate nesting and foraging habitat. Scavengers are exceptionally abundant, but presumably forage in Venezuela and Trinidad. The landbirds are dominated by forest interior species, with fewer forest/grassland edge species. Evidence of frequent overwater dispersal exists for certain species. The breeding season, which for most species is restricted to the early wet season, is more seasonal than it is on Trinidad.

RESUMEN.-Las Islas Bocas ubicadas al norte del Gulfo de Paria, que separa ]a 2 Trinidad del continente de Sudamerica, contienen cinco islas mayores (hasta 4.54 km ), 2 diez is las men ores (hasta 0.08 km ) ymuchos islotes. La vegetaci6n clfmax predominante de las islas relativamente secas incluye bosque litoral y bosque caducifolio estacional encima de suelos derivados de rocas sedimentarias. Se proveen datos sabre la abundancia de 135 especies de aves de las islas mayores basados sobre observaciones generales, conteos puntuales y capturas con redes de niebla (solamente en tres islas). Se registraron solamente 31 especies para las islas menores. De las 135 especies, por Jo menos 34 se reproducen con certeza en las islas, otras 39 presumiblemente anidan, 32 probablemente no anidan pero residen en la region (Venezuela o Trinidad), 25 son migratorias nearticas, dos son migratorias neotropicales, dos son visitas introducidas y una esta extirpada (otras diez son consideradas como hipoteticas). Las aves marinas y las aves acu;iticas costeras son escasas, presumiblemente debido a que el habitat no

62 Avifauna of th e Bocas Islands 63

es adecuado para anidar o alimentarse. Las carrofieras son excepcionalmente abundantes, pero presumiblemente se alimentan en Venezuela o Trinidad. El grupo de aves terrestres es dominado por especies del interior del bosque, con pocas especies que se encuentran en los bordes del bosque. Existe evidencia para Ia dispersion frecuente a traves del agua para ciertas especies de aves. La epoca de nidificacion es restringida al inicio de Ia estacion seca para Ia mayoria de las especies, y es mas estacional que Ia epoca de nidificacion en Trinidad.

KEY WORDS.-abundance, avifauna, Bocas Islands, breeding, distribution, Gulf of Pari a, mist netting, point counts, seasonality, Trinidad, Venezuela

The Gulf of Patia, which separates the con­ 30.3 km, from 61 o53 'W in the west (Patos) to tinental island of Trinidad from the northeastern 61 o36'W in the east (Caledonia); they vary little in coast of South America, is connected to the Carib­ latitude, ranging from l0°38 'N (Patos) to l0°45'N bean Sea at its northern extremity by the notorious (La Isleta). The major island of Patos, which 'Boca del Dragon' or 'Dragon's Mouth'. Scattered belongs to the Republic of Venezuela, is situated within the Dragon's Mouth and at the tips of the south of the Paria Peninsula. Islotes Las Garzas in­ Paria Peni11sula of Venezuela (to the west) a11d the clude three tiny islets off the southeast coast of tl1e Chaguaramas Peninsula ofTrinidad (to the east) are Pari a Peninsula. La Isleta is a minor island located numerous 'teeth', which collectively fotm the just off the northeastern tip of the Pari a Peninsula, Bocas Islands (Fig. I). Although most of these Venezuela; it is the 011ly Bocas Island in the Catib­ islands have been visited at some time or another bean Sea. The remaining islands, situated to the by ornithologists (Chapman 1894, Belcher and east, belong to the Republic of Trinidad and To­ Smooker 1936a, b, 1937a, b, Junge and Mees 1958, bago. Three of the major islands (Chacachacare, Phelps and Phelps 1958, Herklots 1961, S11ow 1962a, Huevos and Monos) form the 'incisors' ofthe Boca b, Snow and Snow 1963, ffrench 1965a-c, I 967a-c, del Dragon (Dragon's Mouth), a I 9.4 km strait 1969a, Temple 1996), there have been no previous between the Paria Peninsula of Venezuela and the attempts to rigorously survey the avifauna of each Chaguaramas Peninsula ofTrinidad. Gaspar Grande island or to summarise the entire avifauna in a and nine minor islands are scattered off the south­ single synthesis. ern coast of Trinidad's Chaguaramas Peninsula. In this paper we provide data on the status, Various topographical and geographical measures abundance and breeding of birds on the Bocas are summarised in Table I. Islands, based on a historical review of earlier Geological histmy. -The Bocas Islands are surveys and more extensive surveys during the composed chiefly of sedimentary limestones with past several years. A more thorough biogeo­ interbedded phyl1ites, schists and conglomerates graphical analysis of the birds of Trinidad, Tobago ranging in age from Jurassic to Cretaceous (Kugler and their satellite islands (including the Bocas 1953, Pierce 1958, Barr 1981). Caves are abundant Islands) will be published elsewhere (Hayes in on some islands, most notably at Patos and Gaspar prep.). Grande. The Bocas Islands presumably connected Venezuela's Paria Peninsula with Trinidad when STUDY AREA water levels were lower during the last glacial pe1iod, ca. I 0,000 ybp (Comeau 1991 ). Although the Geography.-The Bocas Islands comprise an maximum depths in the Dragon's Mouth exceed 400 archipelago of five major islands, ten minor islands m (Kenny and Bacon 1981 ), which is we11 below and many tiny islets in the nmihern Gulf of Paria, estimated sea levels duting the last glacial period which separates Trinidad from the South American (e.g., Imbrie and Imbrie 1976), strong tidal currents continent (Fig. 1). The islands span a distance of have undoubtedly eroded the channels ('bocas') 64 HAYES AND SAMAD

CARIBBEAN SEA

VENE­ ZUELA DRAGON'S MOUTH Huevos Monos TRINIDAD

Cha=h•~~") k;!p,rtllo .-----

Gaspar Gran~ , D Cronstadt p~ GULF OF PARIA

FIG. I. Map of the Bocas Islands. between the islands. The discovery of fossil coral es of mangrove occur in the more sheltered bays reefs dated 1780-3750 ybp off Trinidad's Chagua­ and in the Salt Pond of Chacachacare. The littoral ramas Peninsula (Kenny 1995) indicate that marine woodland extends up to 120m above sea level (on conditions in the northern Gulf of Paria were more Chacachacare; 60 m on Monos), with a canopy 3-1 0 oceanic than at present and that the channels of m high. The canopy of the deciduous seasonal the Dragon's Mouth already existed. Kenny (1995) forest is partially closed, averaging about 10 m in postulated that a relatively recent land-bridge con­ height, but emergent trees may reach 20 m. Of the nected southwestern Trinidad with the mainland of major Bocas Islands, Patos has the shortest forest Venezuela, thus blocking outflows from the Ori­ (N. Johnson et al. unpubl. data). Legumes, agaves noco River into the Gulf of Pari a. and cacti are abundant; palms, lianes and epiphytes Climate.-Situated in the rain shadow of Trin­ are scarce. Many trees are deciduous, losing leaves idad's Northern Range, the Bocas Islands are rela­ from Jan to Apr, with a new flush of leaves sprout­ tively dry, becoming increasingly so from east to ing before the onset of the wet season in May. The west (Berridge 1981 ). During 1935-1940, Cha­ understorey, which includes terrestrial aroids and cachacare averaged only 115 em of rainfall per year bromeliads, is sparse. Natural or man-made clear­ (Chalmers 1965). The wet season extends from late ings are covered by grasses. The vegetation of May through Dec and the dry season from Jan to individual islands has been described in further late May, with the amount of precipitation and the detail for Chacachacare (Darlington 1967), Huevos onset of each season varying greatly from year (Manuel 1967), Monos (Chalmers 1965, Manuel to year (Berridge 1981 ). Although temporary 1965) and the 'Five Islands' (Chaboo 1990). streams occur in the ravines during the wet season, Human activities.-Human activities during the none of the islands has a permanent supply of past few centuries have significantly altered the freshwater. vegetation on most of the islands (e.g., Joseph Vegetation.-The predominant climax vege­ 1838, Carmichael1961, Kelshall1988, Retout 1988). tation of the islands includes littoral woodland The fortifications were built on several of the along the coast and deciduous seasonal forest islands during the late 18th and early 19th cen­ elsewhere (Marshall1934, Beard 1946). Tiny patch- turies. Cotton and citrus plantations thrived on Avifauna of the Bocas Islands 65

TABLE 1. Topographical vmiables for the Bocas Islands, arranged from west to east. Data obtained from topographical maps (unavailable for Venezuelan islands); most elevations are estimated from maps or visual inspection.

Distance (krn) Distance (krn) Planimetric Maximum Distance (km) to big island to any island 2 Island area (km ) elevation (m) to continent or continent or continent Patos 0.81 100 4.6 4.5 4.5 lslotes Las Garzas 0.03 40 0.2 0.2 0.2 La Isleta 0.08 15 0.1 0.1 0.1 Chacachacare 4.09 249 10.4 6.8 1.2 Huevos 1.08 198 13.0 4.6 1.2 Monos 4.54 290 16.7 0.7 0.7 Gaspar Grande 1.58 103 21.1 1.0 0.6 Gasparillo 0.02 35 22.2 0.2 0.2 Cronstadt 0.06 46 25.0 0.6 0.4 Carrera 0.08 40 25.6 0.5 0.4 Rock 0.001 5 28.6 2.2 0.08 Lenagan 0.005 15 28.6 2.2 0.05 Nelson 0.01 15 28 .7 2.4 0.08 Craig 0.0006 20 28 .8 2.2 0.02 Caledonia 0.02 30 28.9 2.2 0.02 Pelican 0.002 5 29.2 2.5 0.15

Chacachacare during the 19th century. Holiday parently remained uninhabited for several decades. homes were established on most of the islands The leper colony of Chacachacare was closed in during the mid-1800s. Whallng stations were estab­ 1984; since then only the buildings beside the light­ lished at Gaspar Grande, Monos and Chacachacare house have been permanently manned. Vacation during the late 19th century, but were soon aban­ homes and permanent residences have reappeared doned as the whales of the region were extirpated. along the coasts ofHuevos (one only), Monos and From 1845-1917, Nelson served as a quarantine Gaspar Grande. The native forest vegetation has station for East Indian immigrants. A colony of up essentially recovered on Patos and Huevos. Al­ to 500 lepers was established on Chacachacare in though large areas have been cleared on Cha­ 1922. cachacare, Monos (especially; fires are often set) Land use in the Bocas Islands changed dra­ and Gaspar Grande, the native forest remains matically during World War ll, when the British largely intact. Cronstadt has been transformed into government expropriated portions of the Cha­ a large limestone mine and Carrera into a prison; guaramas Peninsula and Bocas Islands and leased these are the only islands which remain deforested. them to the United States. The armed forces of Great Britain and the United States constructed ORNITHOLOGICAL HISTORY buildings and paved roads on Patos, Chacachacare and Monos, but all were abandoned shortly after Patos.-Belcher and Smooker(1937b:546) visit­ the war (except for the paved road leading to the ed Patos on three occasions before 1934 (Phelps lighthouse on Chacachacare). Patos was given to and Phelps 1958), but provided little information Venezuela in 1942, and the remaining islands near and no dates. During 3-19 Aug 194 7, R. Urbano col­ Trinidad were gradually returned to Trinidad and lected 147 specimens of 31 species, and observed Tobago in the succeeding decades. Patos has ap- an additional 3 species of birds; the specimens ------··-- --- ··- --- · ------

66 HAYES AND SAMAD

were deposited in the Coleccion Omitologica ffrench (1967a, b) observed and mist-netted birds. Phelps in Caracas, Venezuela (Phelps and Phelps Recent surveys were conducted on 2 Mar 1997 1958). During 4-6 Aug 1962, M. ffrench observed (FEH, IS), 27Nov 1997 (FEH), 17 Feb 1998 (IS) and birds and set up a net for several hr, but caught few 10 Mar 1999 (IS), and noteworthy observations birds (ffrench I 965a, pers. comm.). The only recent from an interisland ferry passing between Huevos survey was that ofFEH and D. B. McNair dming 6- and Monos on 10 May 1998,27 Jun 1999, 15 Jul 8 Jan 1999. 2001, 1 Aug 2001 and 26 Oct 2001 (FEH). Chacachacare.-Dming 23-28 May and on 8 Monos.-During4-7 May 1893, Chapman (1894) Jun 1935, C. F. Belcher observed birds a11d col­ observed 26 species oflandbirds and collected sev­ lected a few for the British Museum in Tring, Great eral for the American Museum ofNatural History1n Britain (Belcher and Smooker1936a, b, 1937a, b).ln New York, USA. On 24 Oct 1953, Junge and Mees 1942, J. M. Abbott observed birds while serving in (1958) collected four specimens for the Rijksmus­ the military garrison (at least during late Mar to eum van Natuurlijke Historie in Leiden, Nether­ May; Herklots 196 I). At some point between Jul lands. On 7 Aug 1960, D. W. Snow (pers. comm.) I 953 and I 961, Herkiots (1961) visited Chacachacare visited the island. During 16-18 May 1964 and 1-3 but provided no dates. On 16 Oct 1958, W. G. Aug 1964, ffrench (1965a-c) observed and mist­ Downs collected a single bird for the Trinidad Re­ netted birds. Recent surveys were conducted on 9 gional Virus Laboratory in Port of Spain, Trinidad Feb 1997 (FEH, IS), 17 Feb 1998 (FEH, IS), 7 Mar (unpubl. catalog). D. W. Snow and B. K. Snow 1999 (IS) and 12 Dec 1999 (FEH), and noteworthy visited the island on 17 Oct 1958, 6, 7 and I 7 Nov observations from an interisland ferry passing be­ 1958, and 13 Apr 1960 (Snow and Snow 1963, tween Huevos and Monos on 26 Oct 2001 (FEH). ffrench 1973:365, 1991 :330, D. W. Snow pers. Gaspar Grande.-G. D. Smooker visited the comm.). T. H. G. Aitken explored the west coast of island on 19 Nov 1921 (Belcher and Smooker Chacachacare in Nov 1958 (Snow 1962b ). During 1937b). On 24 Oct 1953, Junge and Mees (1958) 28-30 May 1966 and 30 Aug to 1 Sep 1968, ffrench collected two specimens for the Rijksmuseum van (I967b, c, 1969a) observed and mist-netted birds. Natuurlijke Historie in Leiden, Netherlands, and W. L. Murphy observed birds on 18 Feb 1990. G. reported a few other species observed. R. P. ffrench White observed birds on 28 Sep 1991 and 22 Aug and M. ffrench visited the island on 22 Sep 1963 1992. On 22 Apr 1995, G. Seutin observed and mist­ and 16-17 Sep 1965, observing 38 species ofbirds. netted birds. During 14-15 Feb 1997, S. A. Temple A li st of 51 species observed from 1983-1993 was observed and mist-netted birds. C. Rooks observed reported by de Verteuil (1993). A banded bird was birds on 10 and 13 Oct 1999, J. Teixeira and G. recovered on 22 Feb 1972 (R. ffrench pers. comm.). Lalsingh on 12-13 Jan 2001, and M. Kenefick on 31 Recent surveys were conducted on 13 and 18 Oct Jan 2002. Our own surveys were conducted on 20 1996 (FEH, IS), 16 Feb 1997 (FEH, IS), 16 and 27 Oct 1996 (FEH, IS), 2-3 Jan 1997 (FEH, IS), 26 Jun Nov 1997 (FEH), 16 Mar 1999 (IS) and 11 Nov 2001 1997 (FEH), 7-8 Nov 1997 (FEH), 2-4 and 9-1 1 Oct (FEH). 1998 (FEH), 5 Nov 1998 (FEH), 14Feb I999 (FEH), Minor Bocas.-Few of the minor Bocas Islands 30 Sep I 999 (IS, S. Bodnar), 1 and 6-8 Oct 1999 (IS, have been adequately surveyed. Belcher and S. Bodnar), 29-31 Oct 1999(FEH), 12-14 Nov 1999 Smooker (1936a) reported eggs obtained at Cron­ (FEH),23Jan 2000(FEH), 16 Aug2000(FEH), 9-11 stadt on 3 Jun 1933 and Ramdial (1972) listed five Mar 2001 (FEH), 23-25 Mar 2001 (FEH), 22-24 Feb additional species of birds from the island. A band­ 2002 (FEH) and 1-3 Mar 2002 (FEH). During the 2-3 ed bird was recovered on Nelson Island in 1969 Jan 1997 survey, N. K. Klein and C. S. Griffiths (Anon. 1971 ). Surveys of the terrestrial fauna of collected nine specimens of birds for the Field Nelson and some of the other 'Five Islands' were Museum of Natural History in Chicago, USA. conducted duri11g 16-21 Sep 1979 by E. Carrington, Huevos.-A sea cave on the north coast was W. Diaz, J. S. Kenny, J. M. Koo and F. Razac and in visited by Chapman (1894) on 5 May 1893 and by May 1987 by G. White (unpubl. reports, Dept. of Snow (1962a, b) in 1959. During 5-7 Jun 1965, Zoology, Univ. of the West Indies). During I 0-11 ------

Avifauna of the Bocas Islands 67

Feb 1995, Temple (1996) surveyed birds 011 the trails or roads with a canopy gap< I 0 m wide, and 'Five Islands' (actually six): Rock, Lenagan, Nelson, a few were conducted near clearings. Birds seen Craig, Caledonia and Pelican. Recent surveys of flying above the forest were excluded from point Gasparillo were conducted on land during J 8 Oct counts. Point counts on different days were often 1996 and by water on 16 Feb 1997 (FEH, IS); ad­ repeated in the same areas, but an effort was made ditional observations were made from Trinidad on not to use the exact same points. All point counts 9 Oct 1998 (FEH). Recent surveys were conducted were conducted during the moming, from 0620-1100 at Nelson on 16 Aug 2000 (FEH) and on Nelson, hr. Craig and Caledonia on 7 Apr 2002 (FEH), where At Patos, FEH conducted 30 point counts dur­ some birds were seen on nearby islands as well. ing 7-8 Jan 1999 (15 each day). At Chacachacare, 11 Nothing is knoW11 regarding the birds of Carrera. point counts were conducted on 20 Oct 1996 (FEH, In Venezuela, La Isleta and Islotes Las Garzas 9; IS, 2), 9 on 3 Jan 1997 (FEH, 3; IS, 6), 10 on 26 Jun were briefly surveyed from a boat on 17 Jan 1999 1997 (FEH), and 5 on I I Oct 1998 (FEH), for a total (FEH, DBM). of 35. At Huevos, 19 point counts were conducted on 2 Mar 1997 (FEH, 11; IS, 8), 3 on 27 Nov 1997 METHODS (FEH), and 8 on 10 Mar 1999 (IS), for a total of30. At Monos, 16 were conducted on 9 Feb 1997 (FEH, The status of each species was defined as: (I) 8; IS, 8), 9 on 17 Feb 1997 (FEH), and 8 on 7 Mar breeding resident confirmed, based on observa­ 1999 (IS), for a total of 33. At Gaspar Grande, 3 tions of nests or recently fledged young; (2) breed­ point counts were conducted on 13 Oct I 996 (lS), ing resident suspected, based on nesting recorded 13 on 18 Oct 1996 (FEH, 8; IS, 5), 9 on 16 Feb 1997 from similar habitat in adjacent Venezuela (Meyer (FEH), and lOon 16 Mar 1999 (IS), fora total of35. de Schauensee m1d Phelps 1978) or Trinidad Abuudance based on mist-netting was cal­ (ffrench 1991 ); (3) non-breeding but locally resident culated as the number of birds captured (including visitor, based on few observations of presumed recaptures) per I 0 net hr, based on 12 m mist nets transients for species known to breed in nearby (e.g., Karr 1981 ). At Chacachacare, birds were mist­ Venezuela or Trinidad; (4) non-breeding but locally netted for 34 net hr during 28-30 May 1966 (ffrench introduced visitor; (5) Nearctic migrant, known to 1967b, c), 44 net hr during 30 Aug to I Sep 1968 breed only in North America; and (6) Neotropical (ffrench 1969a), I 06 net hr ou 22 Apr 1995 (G. migrant, known to breed only in temperate South Seutin), 82 net hr during 2-3 Jan 1997 (FEH, IS, America (see definitions of Hayes 1995). NKK, CSG), an unrecordedperiodduriug 14-15 Feb For each species we accumulated data on the 1997 (SAT), and 312 net hr during 30 Sep and 1, 6 abundance of birds based on three methods: (1) and 7 Oct 1999 (SB, IS), for a total of 578 net hr. At general observations; (2) mist-netting; and (3) point Huevos, birds were mist-netted for 79 net hr during counts. Relative abundance, based on general ob­ 5-7 Jun 1965 (ffrench 1967a, b). At Monos, birds se1vatim1s in the appropriate habitat and season, were mist-netted for 124 net hr during 16-18 May was defined as follows: abundant, 10 or more re­ 1964 aud I I 7 net hr during l-3 Aug 1964, for a total corded daily; common, recorded daily; uncommon, of241 net hr (ffrench 1965a-c). recorded every 2-10 days; rare, recorded at inter­ vals of 11 or more days. RESULTS AN"D DISCUSSION Abundance based on point counts was cal­ culated as the mean number of birds per point Species accounts.-The following accounts for count within a fixed radius of 25 m duriug a 10 min each species include: (1) relative abundance; (2) de­ period, with a minimum distance of 100 m between tails for rare species; (3) extreme migration dates in successive counts (e.g., Wunderle 1994). All point sequence of early and late; (4) evidence for breed­ counts were conducted at least 50 m from the ing; (5) locality of specimens; and (6) miscellaneous coast; most were conducted aloug narrow trails observations. Records for different islands are within forest, but some were conducted along wider given from west to east. Species whose occurrence 68 HAYES AND SAMAD on the Bocas Islands is regarded as hypothetical Monos (Chapman I 894; FEH). are placed within brackets. h1itials of authors and Great Egret (Ardea alba).-A single bird was other observers {see Acknowledgements section) seen south of Patos as it flew eastward on 8 Jan are given in parentheses. A checklist with data on 1999 (DBM). the status, presence and abundance (based on Snowy Egret (Egretta thula).-Four were see11 censuses for major Bocas only) of birds on each flying westward just south of Huevos on 1 Aug island is given in Tables 2 and 3. Museum abbrevi­ 2001 (FEH). ations for specimens include: American Museum of Little Blue Heron (Egretta caerulea).-At Cha­ Natural History, New York, USA (AMNH); Carib­ cachacare single birds seen regularly along coast bean Epidemiology Center {fmmerly Trinidad Re­ and in Salt Pond since 2 Jan 1997 (FEH). gional Virus Laboratory), Port of Spain, Trinidad Yellow-crowned Night-Heron (Nyctanassa vio­ (CAREC); Colecci6n Omito16gica Phelps, Caracas, lacea).-Reported breeding "for years" at Gaspar Venezuela (COP); Natural History Museum (for­ Grande (de Verteuil I993). An adult was seen at merly the British Museum), Tring, Great Britain Chacachacare on 3 Oct 1998 (FEH). An unidentified {BMNH); and Rijksmuseum van Natuurlijke His­ immature night-heron was seen at Chacachacare on torie, Leiden, Netherlands (RNH). Details forrarities 23 Mar 2001 (FEH). reported to the Trinidad and Tobago Rare Bird Scarlet Ibis (Eudocimus ruber).-F1ocks flying Committee (TTRBC) are deposited at the Depart­ over the islands include 36 at Chacachacare on 10 ment of Life Sciences, University of the West Oct 1998 (FEH), 35 at Chacachacare, Huevos and Indies, St. Augustine, Trinidad. Taxonomy is based Monos on 8 Oct 1999 (IS), and 20 at Chacachacare on the American Ornithologists' Union (1998). on 31 Oct 1999 (FEH). Brown Booby (Sula leucogaster).-An im­ Black Vulture (Coragyps atratus).-Roosts on mature was seen flying just north of Huevos on 27 rocky outcrops, tall trees, and man-made structures Jun 1999 (FEH), and two immatures were seen (e.g., buildings, lighthouses). The large population flying from SW of Monos and landing in water just of several hundred birds cannot be supported by SE ofHuevos on 26 Oct 2001 (FEH). the available resources of the Bocas Islands. The Brown Pelican (Pelecanus occidentalis ).- Fre­ islands are probably used mostly for nesting and quently seen flying along coasts or above the roosting; foraging occurs primarily in the dumps islands, occasionally perched. Fair numbers roost and beaches of adjacent Trinidad and Venezuela. in trees on the southwest side of Gasparillo, where Breeding: On 27 Nov 1997, two large nestlings were nesting may occur. Up to 130 were scattered in found below a large rock at Huevos (VM, FEH). On vegetation where nesting may occur on a large rock 18 Oct 1996, two smal111esthngs in one nest and an just north ofHuevos on 27 Jun 1999, 15 Jul 2001, 1 egg in another nest were found under large rocks at Aug 2001 and 26 Oct 2001 (FEH). T11e nearest Gasparillo (FEH). On 16 Aug 2000, a nest with two known breeding colonies are at Punta Uquire, along eggs was found at Nelson {BS et al.). the nmil1 coast of the Paria Peninsula (several Turkey Vulture (Cathartes aura).-Small num­ thousand on a small offshore island and along bers fly above forest or perch in trees. adjacent coast in Jan I 999; FEH, DBM), and at Saut Osprey (Pandion haliaetus).-Occasionally D'Eau Island, along the no1ih coast of Trinidad seen flying or perched in trees along coast. Extreme (ffrench 1969b). dates: 22 Aug 1992 at Chacachacare (GW) and I I Anhinga (Anhinga anhinga).-A male was Mar 2001 at Chacachacare (FEH). seen at Patos on 5 and 6 Aug I 962 (Mff). Reported Gray-headed Kite (Leptodon cayanensis).-A for Gaspar Grande (de Verteui11993). single bird was seen flying over Chacachacare on Magnificent Frigatebird (Fregata magnifi­ I 0 Oct 1999 (CR). cens).-Frequently seen flying along coasts or Hook-billed Kite (Chondrohierax uncinatus).­ above all islands. Fair numbers roost (and possibly A grey-morph adult circled over Chacachacare on nest) at lslotes Las Garzas, Venezuela (FEH, DBM), 24 Mar 2001 (FEH, BDH). and on a tiny islet off the northeast comer of White Hawk (Leucopternis albicollis).-Sing1e Avifauna of the Bocas Islands 69 birds were seen repeatedly at Chacachacare since has greatly expanded in Trinidad, and it has recent­ I 0 Oct 1998 (FEH), at Huevos on 27 Nov 1997 ly attempted nesting on Tobago (D. Finch pers. (FEH), and at Monos on 2 Mar 1997 (FEH). Two comm., FEH). were seen at Gaspar Grande 011 18 Oct 1996 (FEH). Merlin (Falco columbarius).-At Chacacha­ Gray Hawk (Asturina nitida).-Occasionally care, single birds were noted on 7 Nov 1997 and 13 seen or heard in the forest. On 18 Feb I 990, one Nov 1999 (FEH). was observed through a Questar telescope as it Peregrine Falcon (Falco peregrinus).-At Cha­ appeared from near the tip of the Paria Peninsula, cachacare, one or two regularly seen since 30 Oct flew over Chacachacare, and disappeared heading 1999 (FEH). Extreme dates: 30 Oct 1999 (FEH) to 25 toward Trinidad (WLM). Specimen: Patos (COP). Mar 2001 (BDH). Common Black-Hawk (Buteogallus anthra­ Rufous-necked Wood-Rail (Aramides axil­ cinus).-Occasionally seen hunting for crabs along laris).-Usually in humid ravines at lower eleva­ the coasts or in the forested interior. ions; also observed at the Salt Pond of Chacacha­ Roadside Hawk (Buteo magnirostris).-Report­ care (FEH). Heard calhng during May (ffrench edly observed but not collected on Patos in Aug 1965a, 1967a, c) to Oct (FEH). The only recent re­ 194 7 (Phelps and Phelps 1958). Unrecorded from cords (since 1970) are from Chacachacare (FEH) and any island east of Patos i11cluding Trinidad (ffrench Gaspar Grande (de Verteuil 1993); on the other 1991), but has been observed along the adjacent islands it is either overlooked or extirpated by over­ mainland of Venezuela at Macuro (FEH, DBM). hunting. On Patos, Phelps and Phelps (1958) report­ Broad-winged Hawk (Buteo platypterus).-At ed that they were hunted with dogs or by imitating Chacachacare, this species was repmied by Belcher the vocalisations of fledglings. FEH was told by in May 193 5 (Herklots 1961 ); recent sightings in­ residents of Macuro, Venezuela, that hunters fre­ clude a flock of 13 on 20 Oct 1996, one on 7 Nov quently visit Patos, where several Venezuelans 1997, 12 on 30 Oct 1999 and one on 13 Nov 1999 were observed hunting iguanas {Iguana iguana) in (FEH). One was seen flying above Monos on 27 Jan 1999. Breeding: Phelps and Phelps (1958) Nov 1997 (FEH). These birds presumably represent reported that young birds are present on Patos in the migratory Nearctic race platypterus rather than Jul and Aug. A juvenile was seen at Chacachacare the resident race antillarum. Phelps :md Phelps on 11 Oct 1998 (FEH). Specimens: Patos (COP). (1958) rejected an apparent sight record by Smook­ Semipalmated Plover (Charadrius semipalm­ er for Patos (reported toR. Meyer de Schauensee), atus).-Recorded only at Chacachacare during 30 suggesting that it may have been confused with an Aug to 1 Sep 1968 (ffrench 1969a) and on 3 Oct immature Gray Hawk. 1998 (FEH). Short-tailed Hawk (Buteo brachyurus).-Oc­ Greater Yellow legs (Tringa melanoleuca).-At casionally seen soaring overhead. Breeding: Nest­ Chacachacare, sightings include up to three during ed at Chacachacare in Mar 1942 (Herklots 1961). 23-25 Mar 2001 and up to two during 24 Feb to 3 Specimen: Patos (COP). Mar 2002, mostly at Salt Pond (FEH, BDH). Swain son's Hawk (Buteo swainsoni).-A pale­ Lesser Yellowlegs (Tringajlavipes).-One was breasted, pale-headed, light-phased immature was at Salt Pond, Chacachacare, 24 Feb and 3 Mar 2002 seen and heard repeatedly at Chacachacare during (FEH). 29-31 Oct 1999, 13-14 Nov 1999 and 12-13 Jan Solitary Sandpiper (Tringa solitaria).-One (Hayes 2001 ). was seen at Chacachacare on 3 Oct 1998 (FEH). Re­ Zone-tailed Hawk (Buteo albonotatus).-Often ported for Gaspar Grande (de Verteuil 1993) but de­ seen perched in trees or flying over the forest. One scription "wags its tail" (p. 123) clearly refers to the was seen canying an unidentified snake at Patos more common Spotted Sandpiper (see account be­ on 8 Jan 1999 (FEH). low). Yellow-headed Caracara (Milvago chimachi­ Willet (Catoptrophorus semipalmatus).-Three ma).-First recorded at Chacachacare on 17 Mar were seen at Chacachacare on 30 Oct 1999 (FEH). 1942 (Herklots 1962); subsequently its population Spotted Sandpiper (Actitis macularia).-Ob- 70 HAYES AND SAMAD served at the Salt Pond of Chacachacare and along care, ffrench (1967b) reported a nest with eggs dur­ the shorehnes elsewhere. Extreme dates: 1-3 Aug ing 28-30 May 1966. Specimens: Patos (COP). 1964 (ffrench 1965b) and 5 Jun 1965 at Huevos (Plain-breasted Ground-Dove (Columbina min­ (ffrench 1967b, 1991). Specimen: Patos (COP). uta)].-Reported without details for Chacachacare Semipalmated Sandpiper (Calidris pusilla).­ (Herklots 1961) and Gaspar Grande (de Verteuil Recorded at Chacachacare during 30 Aug to 1 Sep 1993), but appropriate savannah habitat absent. 1968 (ffrench 1969a). One was observed at Lenagan Ruddy Ground-Dove (Columbina talpacoti).­ during 16-22 Sep 1979 (JSK, JMK). Usually near clearings. Specimen: Patos (COP). Least Sandpiper ( Calidris minutilla).-A male Blue Ground-Dove ( Claravis pretiosa).-Proba­ was collected at Patos in Aug 1947 (Phelps and bly seasonal. Reported as "fairly common" at Phelps 1958). Specimen: Patos (COP). Monos during 16-18 May 1964 and 1-3 Aug 1964 Laughing Gull (Larus atricilla).-Sporadically (ffrench 1965a-c), and reported without details at observed along the coasts. Gaspar Grande (de Verteuil 1993), but unrecorded [Roseate Tem (Sterna dougallii)].-About 10 during recent surveys. terns possibly of this species were seen flying just White-tipped Dove (Leptotila verreauxi).­ north ofHuevos on 27 Jun 1999 (FEH). Breeding: An occupied nest was reported without Common Tern (Sterna hirundo ).-Observed details at Chacachacare (ffrench 1967c) during 28 -30 along the coasts between 28 Sep (GW) and Jun May 1966, and a nest with two eggs was found at (Anon. 1971). Two band recoveries: one at Nelson Huevos during 5-7 Jun 1965 (ffrench 1967a). Speci­ Island in Jun 1970, which had been banded on mens: Patos (COP). Great Gull Island, NY, USA, on 5 Jul 1969 (Ano11 . Lilac-tailed I Scarlet-shouldered Parrotlet (Tau­ 1971); and one captured at Baleine Bay, Gaspar it batavica I huetii) .-A flock of 20 was seen flying Grande, on 22 Feb 1972, with a USF&WS band eastward high above Chacachacare on 1 Sep 1968 (number not reported) and a green band on the (ffrench 1969a). The birds were most likely the right leg (repmied to RPff). Lilac-tailed Parrotlet, which is considerably more Least Tern (Sterna antillarum).-An immature common in Trinidad (ffrench 1991). was seen at Chacachacare on 3 Oct 1998 (FEH). [Yellow-crowned Parrot (Amazona ochro­ Junge and Mees (1958) observed many in the Boca cephala)] .-Reported for Gaspar Grande (de Verteuil de Monos (presttmably including Monos) on 29 1993), but undoubtedly refers to the more common Jun 1953. Orange-winged Parrot (see next account). Brown Noddy (Anous stolidus).-One was seen Orange-winged Parrot (Amazona amazonica ).­ flying just north ofHuevos on 27 Jun 1999 (FEH). At Gaspar Grande, de Verteuil (1993: 121) reported Rock Dove (Columba livia).-One was seen 200 nesting at the 11orth end of the island for "the landing on the beach at Chacachacare on 30 Oct past four years", flying to Trinidad in the early 1999 (FEH). morning and returning in the evening, but the birds Pale-vented Pigeon (Columba cayennensis).­ were more likely roosting than nesting. An ap­ Observed at Gaspar Grande on 17 Apr 1965 (RPff, parently schizochroic individual, described as Mff). "completely yellow" and presumably lacking mel­ Scaled Pigeon (Columba speciosa).-Possibly anin pigments, was also noted (de Verteuil 1993). seasonal. One bird was seen and several heard FEH noted two flying over Gasparillo from Trinidad calling at Chacachacare on 26 Jun 1997 (FEH, NAT) to Gaspar Grande in the morning of 16 Feb 1997 and at Monos on 17 Feb 1998 (FER, IS). Reported (FER), and 143 were flying from Trinidad to Gaspar for Gaspar Grande (de Verteuil 1993). Grande during 1620-1707 hron 9 Oct 1998 (FEH). At [Eared Dove (Zenaida auriculata)].-Report­ Chacachacare, up to 15 seen regularly siuce 2 Jan ed without details for Gaspar Grande (de Yerteuil 1997 (FEH). Several were seen at Huevos on 2 Mar 1993), but possibly confused with another species. 1997 and I 0 Mar 1999 (FEH, IS) and at Monos on 9 Common Ground-Dove (Columbina passer­ Feb I 997, I 7 Feb 1998, 7 Mar 1999 and I Dec 1999 ina).--Dccurs in clearings. Breeding: At Chacacha- (FER, IS). Avifauna of the Bocas Islands 71

Yellow-billed Cuckoo ( Coccyzus americanu.s).­ chacare, the remains of nests and a few dry seeds Singie birds were seen at Chacachacare on 17 Nov were found by T. H. G. Aitken in a small sea cave 1958 (DWS), 7 Nov 1997 (FEH, PRB, GCC), 4 Oct on the west side of the island in Nov 1958 (Snow 1998 (FEH) and 8 Oct 1999 (IS). A female was col­ 1962b). In a sea cave at Huevos, Chapman (1894) lected at Monos on 4 May 1893 (Chapman J 894). estimated a population of 200 on 5 May 1893; in Specimen: Monos (AMNH). 1959, Snow (1962b) estimated a population of 300 Mangrove Cuckoo (Coccyzus minar).-Pos­ birds in the cave and described it as a single long sibly seasonal. Several birds were seen aud heard chamber about 30m high with an entrance about 5 in deciduous forest aud iu mangroves at Chaca­ m high . Breeding: At Cbacachacare, the remains of chacare on Oct/Nov 1958 (DWS), 3 Jan 1997 (IS, nests reported in Nov 1958 (Snow 1962b) provide NKK, FEH), 11 Oct 1998 (FEH) and 13 Nov 1999 circumstantial evidence for a former breeding colo­ (FEH). A female was collected at Monos on 24 Oct ny. A "laying" female specimen was obtained at 1953 (Junge and Mees 1958). One was seen in Huevos on 5 May 1893 {Chapman 1894). Specimen: deciduous forest at Gaspar Grande on 16 Nov 1997 Huevos (AMNH). (FEH). Breeding: one seen feeding another at Rufous Nightjar (Caprimulgus rufus).~Heard Chacachacare in 1958 (date not provided; DWS). singing from Mar (FEH) to Jun (ffrench 1965a, Specimen: Monos (RNH). 1967a, c). Dark-bi lied Cuckoo ( Coccyzus melacor;ph­ White-tailed Nigh~ar (Caprimulgus cayen­ u.s).-Possibiy seasonal. A male and tl1ree females nensi.s).-A small nighijar, almost certainly of this were collected at Patos in Aug 1947 (Phelps and species, was seen at Patos on 6 Aug 1962 (Mff). At Phelps 1958); none were found in Jan 1999 (FEH). Chacachacare, heard calling from Mar to Nov Specimens: Patos (COP). {FEH). Breeding: At Chacachacare, two nestlings Striped Cuckoo (Tapera naevia).-Heard cal­ were found at a nest during 28-30 May 1966 ling at Monos during 16-18 May and 1-18 Aug 1964 (ffrench 1967c). (ffrench 1965b); not recorded subsequently. Common Potoo Nyctibius griseus.-At Gaspar [Little Cuckoo (Piaya minuta)].-Reported for Grande, de Verteui1 (1993: 121) reported hearing its Gaspar Grande (de Verteuill993), but possibly con­ unmistakable "plaintive cry". fused with another species. Chestnut-collared Swift ( Cypseloides rutilus).­ Smooth-bj]]ed Ani (Crotophaga ani).-A male At Huevos, several were observed flying in and out was collected at Patos in Aug 1947 (Phelps and of a sea cave, where breeding presumably occurred, Phelps 1958). Reported at Gaspar Grande (de Ver­ in 1959 (Snow 1962a). teuil 1993). Single birds were seen and heard at Short-tailed Swift (Chaetura brachyura).­ Chacachacare on 26 Juu 1997 (FEH, JLV, NAT) and Ubiquitous above islands; presumably breeds in Gaspar Grande on 16 Mar 1999 (IS). Specimen: Pat­ trees. Breeding: A set of 3 eggs was obtained at os (COP). Cronstadt on 3 Jun 1933 (Belcher and Smooker [Barn Owl (Tyto alba)].-An old but intact owl 1936a). An incubating female was at Nelson on 16 pellet presumably belonging to this species was Aug 2000 (FEH). found in the abandoned building at Patos on 7 Jan Rufous-breasted Hermit (Glaucis hirsuta).-At 1999 (FEH). The pellet contained a skeleton of a rat Chacachacare, a presumed vagrant was seen near (Rattus sp., presumably R. rattus) tightly packed the Salt Pond on 31 Oct 1999 (FEH). At Monos, it within its fur; Rattus sp. has recently been reported was regularly observed in relatively humid, low­ from Chacachacare (Lall and Hayes 1999). elevation forest at Grand Fond Bay, where breeding Tropical Screech-Owl (Otus choliba).-Heard may occur. calling from Feb (FEH) to Nov (Herklots 1961 ). Black-throated Mango (Anthracothorax nigri­ Fenuginous Pygmy-Owl ( Glaucidium bra.sil­ collis).-Occasionally seen at flowering plants, usu­ ianum).-Heard calling during Feb (FEH, IS) and ally at forest edges. Only one record from Chaca­ May (ffre11ch 1967b). chacare on 22 Aug 1992 (GW). Oilbird (Steatornis caripensis).-At Chaca- Ruby-topaz Hummingbird ( Chrysolampis mos- 72 HAYES A."'D SAMAD quitus).-At Chacacbacare, one was seen on 28 Sep 1936b). 1991 (GW) and a male was seen on 14 Nov 1999 Plain-brown Woodcreeper (Dendrocincla fuli­ (FEH). At Monos, an immatme male was captured ginosa).-At Chacachacare, one was seen and well on 3 Aug 1964 (ffrench 1965c) and a male was seen described on 2 Jan 1997 (VLJ), and one was cap­ on 7 Mar 1999 (IS). Also observed at Gaspar tured on 14 Feb 1997 (SAT). Three unidentified Grande on 17 Apr 1965 (RPff, Mff). woodcreepers (a pair and a solitary individual) seen Tufted Coquette (Lophornis ornata).-At Cha­ on 10 Oct 1998 (FEH) may have been this species. cachacare, a female was seen on 7 Nov 1997 (FEH, These observations provide evidence for a small PRB, GCC) and a male on 13 Nov 1999 (FEH). resident population; this species may be a recent Blue-chinned Sapphire (Chi orestes notatus).­ immigrant. Army ants, with which this species often Observed at Monos dming 16-18 May 1964 associates (ffrench 1991 ), have not yet been (ffrench 1965b). A pair was seen at Monos on 7 recorded on any of the Bocas Islands (C. K. Starr Mar 1999 (IS). pers. comm.). Blue-tailed Emerald ( Chlorostilbon mellisu­ Straight-billed Woodcreeper (Xiphorhynchus gus).-Occasionally seen at flowering plants, usual­ picus).-A single bird was captured and photo­ ly at forest edges. graphed at Chacachacare on 1 Oct 1999 (SB, IS). A Copper-rumped Hummingbird (Amazilia toba­ foraging individual was seen at Gaspar Grande on ci).-Ubiquitous in forest interior and at forest 16 Mar 1999 (IS). edges. Patos is reportedly inhabited by the race Black-crested Antsh1ike (Sakesphorus cana­ caudata (Phelps and Phelps 1958) whereas the densis).-Aithough reported at Gaspar Grande in other islands are inhabited by the race erythronota 1953 (Junge andMees 1958), 1963 and 1965 (RPff, (ffrench 1991 ). The vocalisations on Patos seemed Mff), and apparently observed between 1983 and distinct (FE!-I). Breeding: On Patos, two large nest­ I 993 by de Verteuil ( 1993), we failed to find any dur­ lings fledged from a nest on 7 and 8 Jan 1999, re­ ing recent surveys. Breeding: A nest with two nest­ spectively, and two old nests were found (FEH, lings was found at Monos on 18 May 1964 (ffrench DBM). Specimens: Patos (COP) 1965a). [White-tailed/Violaceous Trogon (Trogon viri­ Barred Antshrike (Thamnophilus doliatus).­ dislviolaceus)].-Recorded only at Gaspar Grande, At Chacachacare, a male was captured on 14 Feb where heard on 22 Sep 1963 (RPff, Mff). 1997 (SAT), and three males were seen on 10 Oct Belted Kingfisher (Ceryle alcyon).-Single 1998 (UWI students), providing evidence for a birds were seen along the coasts of Chacachacare small, previously undetected population; however, on 14 Apr (year not given; Herklots 1961 ), 11 Oct no females have yet been observed. This species 1998 (GG) and 31 Jan 2002 (MK), Monos on 2 Jan may be a recent immigrant. 1997 (FEH), and Gaspar Grande on 17 Apr 1965 White-fringed Antwren (Formicivoragrisea).­ (RPff, Mff). Restricted to Chacachacare, occurring throughout Red-crowned Woodpecker (Melanerpes rubri­ forest. A report for H uevos (ffrench 1973, 1991) capillus).-Restricted to Patos. Breeding: Report­ appears to be in error. Breeding: At Chacachacare, edly nests during Apr and May (Belcher and a nest with two eggs was found on 8 Jun I 935 Smooker 1936b, Phelps aud Phelps 1958). Nesting (Belcher and Smooker 1936b ), and fledglings were holes were ubiquitous in Jan 1999 (FEH, DBM). noted during 30 Aug to 1 Sep 1968 (ffrench 1969a). Specimens: Patos (COP). Specimens: Chacachacare (BMNH, FMNH). Crimson-crested Woodpecker ( Campephilus Southern Beardless-Tyrannulet ( Camptostoma melanoleucos).-Observed at Monos during 16-18 obsoletum).-Seeming1y occurs in more humid May 1964 (ffrench 1965b ). forests than the following species. Specimen: Patos Pale-breasted Spinetail (Synallaxis albes­ (COP). cens).-Occasionally found singing in brushy areas Mouse-colored Tyrannulet (Phaeomyias muri­ at forest edges. Breeding: An old nest was found at na).-Seeming1y occurs in drier forests than the Chacachacare in May 1935 (Belcher and Smooker preceding species, with which it is easily confused. Avifauna of the Bocas Islands 73

Calls described as a "thin peeet or czert, or a quick 1935 (Belcher and Smooker 1937 a). At Monos, two chatter" (ffrench 1991 :304), or as a chuwee with a fledglings were seen on 11 May 1964 and a nest slight double-noted effect, rising slightly in pitch with three small nestlings was found on 18 May (FER); these descriptions differ from those reported 1964 (ffrench 1965a). Specimens: Patos (COP); Cha­ in South America by Ridgely and Tudor (1994). cachacare (FMNH); Monos (RNH); Gaspar Grande Reported for Patos (Mff), but possibly confused (RNH). with the Southern Beardless-Tyrannulet, which was Great Kiskadee (Pitangus sulphuratus).- Oc­ previously reported (Phelps and Phelps 1958). curs mostly at forest edges and along shore-lines. Breeding: a fledgling was captured on 30 Sep 1999 Breeding: A nest with two eggs was found at at Chacachacare (SB). Monos on 18 May 1964 (ffrench 1965a). [Forest Elaenia Myiopagis gaimardii].-Repor­ Boat-billed Flycatcher (Megarynchus pitan­ ted at Chacachacare (Rerklots 1961 ), but no detai Is gua).--Qccurs throughout forest. Although repor­ provided and unreported subsequently. ted on Patos by Phelps and Phelps (1958), none Yellow-bellied Elaenia (Elaeniajlavogaster).­ was heard or observed duri11g 6-8 Jan 1999 (FER). Occurs primarily at forest edges or along coast. Streaked Flycatcher (Myiodynastes maculat­ Specimens: Patos (COP). us).-Possibly seasonal; recorded between dates of Small-bi lied Elaenia ( Elaenia parvirostris).-An 9 Feb 1999 at Monos (IS) and 1-3 Aug 19 at Monos adult was captured at Chacachacare on 30 May (ffrench 1965:b). Breeding: Two nestlings were 1966 (ffrench 1967c). found in a nest at Huevos during 5-7 Jun 1965 Northern Scrub-Flycatcher (Sublegatus aren­ (ffrench 1967a). arum).-Occurs throughout forest. Specimens: Tropical Kingbird (Tyrannus melancholicus).­ Patos (COP); Chacachacare (FMNH). Occurs primarily at forest edges or along coast. Yellow-breasted Flycatcher ( Tolmomyias jlavi­ Specimens: Patos (COP). ventris).-Occurs in the forest canopy of the more Gray Kingbird (Tyrannus dominicensis).-Ob­ humid ravines. At Chacachacare, reported only on served only at Monos during 16-18 May 1964 15 Feb 1997 (SAT). Breeding: At Monos, nesting (ffrench 1965b). was reported during 16-18 May 1964 (ffrench Fork-tailed Flycatcher (Tyrannus savana).­ 1965b). Specimens collected at Patos in Aug 194 7 were re­ White-throated Spadebill (Platyrinchus my­ ferred to the nominate race savana (Phelps and staceus).-One seen in a moist ravine at Chaca­ Phelps 1958). At Chacachacare, up to 25 noted chacare on 20 Oct 1996 (FER). Several recorded at between 16Aug2000(FEH)and28Sep 1991 (GW). Monos during 16-18 May 1964 and 1-3 Aug 1964 At Monos, several were noted on 7 Aug 1960 (ffrench 1965b). Breeding: At Monos, nesting was (DWS). Specimens: Patos (COP). reported during 16-18 May 1964 (ffrench 1965b). White-winged Becard (Pachyramphus poly­ Bran-colored Flycatcher (Myiophobus fasci­ chopterus).-A few individuals were observed at atus).-Breeding: Fledglings were noted at Cha­ Monos during 16-18 May 1964 and 1-3 Aug 1964 cachacare duri11g 30 Aug to l Sep 1968 (ffrench (ffrench l965b). 1969a). Specimens: Patos (COP). White-bearded Manakin (Manacus manac­ Tropical Pewee (Contopus cinereus).-A soli­ us).-An adult female with a brood patch was cap­ tary bird was well observed and heard singing re­ tured at Monos on 2 Aug 1964 (ffrench 1965c). peatedly at Monos on 17 Feb 1998 (FEH). Yellow-throated Vireo (Vireo jlavifrons).-At Fusco us Flycatcher (Cnemotriccus fuscatus ).­ Chacachacare, one was captured on 13 Apr 1960 Occurs throughout forest. Breeding: At Monos, (ffrench 1973, 1991). nesting was rep01ted during 16-18 May 1964 Red-eyed Vireo (Vireo olivaceus).-Highly sea­ (ffrench 1965b). Specimens: Patos (COP). sonal; apparently the most common land bird during Brown-crested Flycatcher (Myiarchus tyran­ the breeding season. Recorded between dates of 15 nulus).-Occurs throughout forest. Breeding: A pair Feb 1997 at Chacachacare (SAT) and 30 Aug to I was building a nest at Chacachacare on 23 May Sep 1968 at Chacachacare (ffrench 1969a). Breeding: 74 HAYES AND SAMAD

At Patos, Phelps and Phelps (1958) reported large Blackpoll Warbler (Dendroica striata).-At fledglings during 3-19 Aug 1947. At Monos, nest­ Chacachacare, one was collected on 16 Oct 1958 ing was reported during 16-18 May 1964 (ffrench (WGD), one was mist-netted, one washed up on the 1965b). Specimens: Patos (COP). beach and another was seen on 17 Oct 1958 (DWS), Gray-breasted Martin (Progne chalybea).­ and many were seen on 7 Nov 1958 (DWS). Speci­ Often flying overhead and perching on cliffs, where men: Chacachacare (CAREC). it presumably nests. Specimens: Patos (COP). American Redstart (Setophaga ruticilla).-At White-winged Swallow (Tachycineta albi­ Chacachacare, the species was observed between venter).-At Monos, up to two birds were seen 30 Aug and 1 Sep (ffrench 1969a), a female was along the south coast and in Grand Fond Bay on 2 seen on 20 Oct 1996 (FER, HN), and one was seen Mar 1997, 27Nov 1997 and 17 Feb 1998 (FER, TS). on 14 and 15 Feb 1997 (SAT). A female was noted This species has been expanding its range on Trin­ at Monos on 7 Mar 1999 (IS). idad, where it now occurs in extreme northeastem Northern Waterthrush (Seiurus noveboracen­ Trinidad (Hayes et al. 1998). sis).-Occurs primarily along the shorelines. Extreme Southem Rough-winged Swallow (Stelgidop­ dates: 4 Oct 1998 at Chacachacare (FER) and 25 teryx ruficollis).-Occasionally seen catching in­ Mar 2001 at Chacachacare (FEH). sects over clearings. Golden-crowned Warbler (Basileuterus culici­ Bam Swallow (Hirundo rustica).-Single birds vorus).-Occurs in the relatively humid forest ra­ were noted at Chacachacare and Nelson on 16 Aug vines. The report of this species from Chacacha­ 2000 (FER, MK). care by Herklots (1961) is credible, but there have House Wren (Troglodytes aedon).-Occurs in been no subseque11t records. forest edges and, surprisingly, well within the Bananaquit (Coereba flaveola).-Occurs forest interior. Breeding: At Chacachacare, an adult throughout the forest, but is surprisingly absent was seen carrying food inside a building on 30 Oct from Patos. Breeding: Two nestlings were observed 1999 (FEH). At Monos, nesting was reported dur­ in a nest at Chacachacare during 28-30 May 1966 ing 16-18 May 1964 (ffrench 1965b). Specimens: (ffrench 1967c) and a pair was observed attending Patos (COP); Chacachacare (FMNH). a nest at Huevos during 5-7 Jun 1965 (ffrench Bare-eyed Robin (Turdus nudigenis).-Occurs 1967a). Another occupied nest was reported at in the more humid forests. Specimen: Patos (COP). Chacachacare during 30 Aug to 1 Sep 1968 (ffrench Tropical Mockingbird (Mimus gilvus).-Occurs l969a). Specimens: Chacachacare (FMNH). primarily in clearings or along the coast. Breeding: [Bicolored Conebill (Conirostrum bicolor)].­ At Chacachacare, a nest with two nestlings and an RepOlted from Monos (ffrench 1973, 1991), but no egg was found during 28-30 May 1966 (ffrench details provided. 1967c), two fledglings were heard on 26 Jun 1997 White-lined Tanager (Tachyphonus rufus).­ (NAT, FEH), and a nestlings were seen on 23 Feb Usually seen in pairs in the forest. Breeding: At 2002 (FEH). An old nest was at Nelson on 16 Aug Monos, nesting was reported during 16-18 May 2000 (FER). 1964 (ffrench 1965b). Tropical Parula (Parula pitiayumi).-Occurs Scarlet Tanager (Piranga olivacea).-A colour throughout the forest, but is surprisingly absent photograph of an adult male was taken by an from Patos. Breeding: Fledglings were noted at unlmown lady at Monos in Apr 1995; the photo­ Chacachacare during 16 Aug 2000 (FER) to 1 Sep grap11 was submitted by GG to tl1e TTRBC and 1968 (ffrench 1969a). Specimen: Monos (RNH). subsequently accepted (ffrench and Hayes 1998; Yellow Warbler (Dendroica petechia).-At TTRBC 1996-13). Chacachacare, single birds were seen 011 28 Sep Blue-gray Tanager (Thraupis episcopus).-Ap­ 1991 (GW), 1 I Oct 1998 (FEH), 5 Nov 1998 (FER, parently more common than Palm Tanager in the WKH) aud 30 Oct 1999 (FER). Given its abundance Bocas; in Trinidad, the Palm Tanager is more in Trinidad (ffrench 1991 ), its scarcity in the Bocas common (Hayes unpubl. data). Breeding: At Mon­ Islands is puzzling. os, nesting was reported during 16-18 May 1964 Avifauna of the Bocas islands 75

( ffrench 1965b ). was not observed in May 1964, but was found to Palm Tanager (Thraupis palmarum).-Qften be "common" in Aug 1964 (ffrench 1965c). Ob­ associates with the Blue-gray Tanager. Specimens: setved at Gaspar Grande on22 Sep 1963 (RPff, Mff). Patos (COP). Breeding: At Monos, a nest with two nestlings was Trinidad Euphonia (Euphonia trinitatis).­ found on 2 Aug 1964 (ffrench 1965c). Heard at Monos during 16-18 May 1964 (ffrench Ruddy-breasted Seedeater (Sporophila min­ 1965b). uta).-Possibly extirpated. At Chacachacare, ffrench Golden-rumped Euphonia (Euphonia cyano­ (1967c) captured two birds during28-30 May 1966, cephala).-Two were seen at Chacachacare on 28 but there have been no recent records. At Monos, Sep 1991 (GW). it was not observed in May 1964, but was found to Red-legged Honeycreeper (Cyane1pes cyan­ be "fairly common" in Aug I 964 (ffrench 1965b). eus).-Possibly seasonal; recorded only during Apr Obsetved at Gaspar Grande on 22 Sep 1963 (RPff, (GS) to Jun (ffrench 1965b, c, J967b). Mff). Two pairs were reported at Nelson duting 16- Blue-black Grassquit ( Volatinia jacm-ina).­ 21 Sep 1979 (EC, WD , JMK, FR). Occurs mostly at forest edges, but on Monos Lesser Seed-Finch ( 01yzoborus angolensis).­ obsetved within thick secondary forest (FEH). Possibly extirpated. At Monos, it was not observed Specimens: Patos (COP). in May 1964, but was found to be "fairly common" Gray Seedeater (Sporophila intermedia).-Pos­ in Aug 1964, when two birds were captured (ffrench sibly extirpated; extensively trapped for aviculture. 1965b, c). Regarded as "uncommon" at Monos (ffrench Black-faced Grassquit (Tiaris bicolor).-Resi­ 1965b) , but not recorded subsequently. This and dent in clearings and forest edges at Chacachacare. the other species of Sporophila require clearings At Huevos, recorded only by ffrench (1967a), who with grass. All are extensively trapped for avi­ captured two birds near the beach of Torture Bay culture. during 5-7 Jun 1965 (ffrench 1967 a). Reported at [Variable Seedeater (Sporophila americana)] .­ Nelson during 10-11 Feb 1995 (Temple 1996), but In May 1935, C. F. Belcher was shown a captive may have been Blue-black Grassquits instead. male at Chacachacare and was told by the light­ Streaked Saltator (Saltator striatipectus).- Oc­ house keeper that it had been lured into a cage in curs throughout forest. Breeding: At Chacachacare, 1934 (Belcher and Smooker 1937b). If indeed it was clutches of 2 and 3 eggs were found on 23 and 24 captured at Chacachacare, it may have been a pet May 1935, respectively (Belcher and Smooker which escaped from the Leprosarium. Thus its 1937b); fledglings were seen on 26 Jun 1997 {NAT, origin remains suspect. FEH) and during 30 Aug to 1 Sep 1968 (ffrench Yellow-bellied Seedeater (Sporophila nigri­ 1969a). Specimens: Patos (COP); Monos (RNH); collis).-Possibly seasonal. Four specimens were Gaspar Grande (RNH). taken on Patos in Aug 1947 (Phelps and Phelps Grayish Saltator (Saltator co erulescens).-lt 1958). At Chacachacare, it has been recorded reg­ remains unknown how this species and its sym­ ularly between the dates of28-30 May 1966 (ffrench patric congener (previous species) partition re­ 1967c) and 5 Nov 1998 (FER), with as many as 30 sources. Breeding: A nest with an egg was found at present during 4-11 Oct 1998 (FEH). At Monos, Chacachacare during 28-30 May 1966 (ffrench ffrench ( 1965b) regarded the species as "uncom­ 1967c). mon" to "fairly common", but there have been no Rose-breasted Grosbeak (Pheucticus ludovici­ subsequent records. Reported for Gaspar Grande anus).-A female was observed at Chacachacare on (de Verteuill993). Breeding: At Chacachacare, a 22 Apr 1995 (GS); the record was accepted by the fledgling was being fed on 4 Oct 1998 (FEH). TTRBC (ffrench and Hayes 1998; TTRBC 1996-16). Specimens: Patos (COP). Bobolink (Dolichonyx oryzivorus).-Qne was Lesson's Seedeater (Sporophila bouvron­ seen and heard calling repeatedly near the light­ ides).-Qne male (possibly two) was seen at Chaca­ house ofChacachacare on 4 Oct 1998 (FEH) . chacare on 4 and 10 Oct 1998 (FEH). At Monos, it Carib Grackle (Quiscalus lugubris).-At Cha- 76 HAYESANDSAMAD

TABLE 2. A vi fauna of the major Bocas Islands. Species within brackets are regarded as hypothetical. Status: BR =breeding resident confirmed; B? = breeding resident suspected; EX = extirpated, breeding status unknown; IV= introduced visitor; RV =non-breeding but locally resident (Venezuela or Trinidad) visitor; NA = Nearctic migrant; NT= Neotropical migrant; ? = hypothetical (see Methods for definitions). Abun-dance: A = abundant; C = common; U =uncommon; R =rare (see Methods for definitions). For each island (from westto east): PC = mean birds detected per point count; MN =mean birds captured per 10 mist net hr; + = recorded, but not during point counts; - = not recorded; ? = hypothetical; '" = breeding confirmed (see Results).

Chaca- Gaspar Patos chacare Huevos Monos Grande Sta- A bun- Species tus dance PC PC(MN) PC(MN) PC(MN) PC Brown Booby RV R + + Brown Pelican s~ A + + + + + Anhinga RV R + + Magnificent Frigatebird RV A + + + + + Great Egret RV R + Snowy Egret RV R + Little Blue Heron RV R + Yellow-crowned Night-Heron BR R + +* Scarlet Ibis RV R + + + Black Vulture BR A 3.98 0.09 0. 17* + + Turkey Vulture B? c + + + 0. 03 + Osprey NA u + + + + + Gray-headed Kite RV R + Hook-billed Kite RV R + White Hawk s~ u + + + + Gray Hawk B? u + + 0.03 + 0.03 Common Black-Hawk s~ u 0.03 + + + + Roadside Hawk RV R + Broad-winged Hawk NA u + + Short-tailed Hawk BR u + +* + Swainson's Hawk NA R + Zone-tailed Hawk B? c 0.03 + + + + Yellow-headed Caracara B? u + + + + Merlin NA R + Peregrine Falcon NA u + Rufous-necked Wood-Rail BR u +* + + + + Semipalmated Plover NA u + Greater Y ellowlegs NA R + Lesser Yellowlegs NA R + Solitary Sandpiper NA R + Willet NA R + Spotted Sandpiper NA c + + + + + Semipalmated Sandpiper NA u + Least Sandpiper NA R + Laughing Gull RV u + + + + [Roseate Tern] ? ? ? Common Tern NA u + + + + Least Tern RV R + + BroWll Noddy RV R + Rock Dove IV R + Pale-vented Pigeon RV R + Avifauna of the Bocas islands 77

TABLE 2 continued.

Chaca- Gaspar Patos chacare Huevos Monos Grande Sta- A bun- Species Ius dance PC PC(MN) PC (MN) PC(MN) PC Scaled Pigeon B? u + + + [Eared Dove] ? ? ? Common Ground-Dove BR u + + [Plain-breasted Ground-Dove] •) ? ? ? Ruddy Ground-Dove B? u + + (0.04) + Blue Ground-Dove RV R + (0.21) + White-tipped Dove BR c 0.13 0.17* (0.02) 0.10* 0.15 (0.21) 0.51 Parrotlet sp. RV R + [Yellow-crowned Parrot] ? ? ? Orange-winged Parrot RV u + + 0.15 + Yellow-billed Cuckoo NA u + + Mangrove Cuckoo BR u 0.11 * + + Dark-hilled Cuckoo B? u + Striped Cuckoo B? R + [Little Cuckoo] ? ? ? Smooth-billed Ani RV R + + O.Q3 [Bam Owl] ? ? ? Tropical Screech-Owl B? u + (0.02) + + + f'enuginous Pygmy-Owl B? u + 0.17 Oilbird BR u ? +* Rufous NighDar B? u + + + White-tailed NighDar BR u ? +* (0.02) Common Potoo B? R + Chestnut-collared Swift B? R + Short-tailed Swift B? A + 0.03 (0.03) + (0.13) + + Rufous-breasted Hennit B? c + 0.15 (0.33) Black-throated Mango B? u + + + 0.03 Ruby-topaz Hummingbird B? R + O.D3 (0.04) + Tufted Coquette RV R + Blue-chinned Sapphire RV R 0.06 Blue-tailed Emerald m u + (0.22) + + Copper-rumped Hununingbird BR c 1.00* 0.20 (0.07) 0.20 0 39 (0.17) 0.31 [White-tailed/Violaceous Trogon] ? ? ? Belted Kingfisher NA u + + + Red-crowned Woodpecker BR c 0.67* Crimson-crested Woodpecker RV R + Pale-breasted Spinetail BR u +* + 0.12 (0.04) Plain-brown Woodcreeper B? R + Straight-billed Woodcreeper RV R + (0.02) 0.03 Black-crested Antshrike BR c 0.43 (0.13) 0.39* (0.33) + Barred Antshrike B? R + White-fringed Antwr~n BR A 1.46* (0.66) Southern Beardless-Tyrannulet B? u + 0.03 0.13 027 Mouse-colored Tyrannulet BR c ? 0.06~ (0.57) 0.03 + [Forest E1aeina] ? ? ? Yellow-bellied Elaenia B? u + 0.06 (0.03) 0.03 (0.13) 0.52 0.17 Small-billed Elaenia NT R + (0.02) Northern Scrub-Flycatcher B? c 003 0.09 (0.12) + (0.38) 0.03 + 78 HAYES AND SAMAD

TABLE 2 continued.

Chaca- Gaspar Patos chacare Huevos Monos Grande Sta- Abun- Species Ius dance PC PC(MN) PC (MN) PC (MN) PC Y cllow-breasted Flycatcher BR c + +(0.13) 0.12* White-throated Spadebill BR R + +* (0.12) Bran-colored Flycatcher BR u + +* (0.12) 0.03 (0.13) 0.03 (0.1 7) Tropical Pewee RV R + Fuscous Flycatcher DR c 0.37 + (0.12) 0.10 (1.65) +* (0.62) Drown-crested Flycatcher BR A 1.00 0.46 (0.45) 0.67 (0.25) 0.15* (0.17) 0.23 Great Kiskadee DR c 0.03 + (0.05) 0.03 0.30* (0.08) 0.86 Doat-billed Flycatcher B? c + 0.09 0.03 0.15 0.34 Streaked Flycatcher BR u + (0.02) +* 0.30 (0.12) 0.09 Tropical Kingbird D? c + + 0.03 + 0.03 Gray Kingbird RV R + Fork-tailed Flycatcher NT u + + + White-winged Becard RV R + White-bearded Manakin RV R + (0.04) Yellow-throated Vireo NA R + Red-eyed Vireo BR A +* 0.80 (0.74) 0.43 (2.78) 0.12* (0.71) 0.06 (Mar-Sep) 2.80 (1.56} 0.48 (2.78) 0.50 (0.71) 0.20 Gray-breasted Martin D'' c + + + + 006 White-winged Swallow RV R + Darn Swallow NA R + Southern Rough-winged Swallow RV u + (0.02) + + House Wren 13R A 0.60 0.29* (0.19) 0.80 (1.14) 0.42* (0.29) 0.20 Bare-eyed Robin D? c 0.10 0.11 (0.12) 0.17 (0.63) 0.33 (0 .66) 0.34 Tropical Mockingbird BR c 0.09* (0.1 0) 0.03 (0.13) 0.06 0.34 Tropical Paru1a BR A 1.00* (0.14) 0.97 0.64* 0.20 Yellow Warbler NA u + Dlackpoll Warbler NA R + American Redstart NA u 0.03 + (Sep-May) 0.04 Northern Waterthrush NA c 0.09 (0.09) 0.1 5 0.03 (Sep-May) 0.12 (0.12) Golden-crowned Warbler B? u + 0.03 (0.13) + (0.04) Bananaquit BR A 0.54* (0.45) 0.60* (0.25) 1.64*(1.41) 0.14 [Bicolored Conebill] ? ? ? White-lined Tanager BR c 0.29 (0.28) 0.37 (0.51) 0.85* (1.66) 0.54 Scarlet Tanager NA R + Blue-gray Tanager BR c 0.17 (0.03) 0.10 (0.51) 0.24* (0.17) 0.51 Palm Tanager B? u 0.07 0.03 0.13 0.15 0.23 Trinidad Euphonia B? R + Golden-mmped Euphonia RV R + Red-legged Honeycreeper B? u + (0.02) 0.10 (0.51) + (0.08) + Blue-black Grassquit D? c + 0.03 (0.02) + 0.09 0.09 Gray Seed eater B? R + [Variable Seedeater] ? ? ? Yellow-bellied Seedeater BR u + +* (0.03) + (0.04) + Lesson' s Seedeater DR R + +* + Ruddy-breasted Seedeater 8? R + (0.03) + + Lesser Seed-Finch B? R + (0 .12) ------

Avifauna of the Bocas Islands 79

TABLE2 continued.

Chaca- Gaspar Patos chacare Huevos Monos Grande Sta- Abun- Species Iu s dance PC PC (MN) PC(MN) PC (MN) PC Black-faced Grassquit B? c + (0.05) + (0.25) Streaked Salta tor BR c 0.27 0.09* (0.29) 0.13 (0.51) +* (0.08) 0.17 Grayish Saltator BR u 0.03* (0.03) 0.03 0.30 (0. 12) 0.14 Rose-breasted Grosbeak NA R + Bobolink NA R + Carib Grackle RV R + + + Shiny Cowbird B? u + (0.02) 0. 17 (0.13) 0.03 Yellow Oriole DR A. 0.40* 0.20* (0.03) 0.07* 0.06* (0. !2) 1.00* Crested Oropendola RV R + Yellow-fronted Canary IV R + Red Siskin EX R + +

cachacare, one was noted on 15 Feb 1997 (SAT) vagrant or a locally breeding resident on the Bocas and a singing male was seen near the lighthouse on Islands. At Monos, Chapman ( 1894) reported ob­ 26 Jun 1997 (FEH, VLJ, NAT). On 10 May 1998, a serving two individuals feeding on the fruit of a female flew aboard the interisland ferry as it passed large cactus during 4-7 May 1893; a single speci­ between Huevos and Monos, hitched a lide for 20 men was collected (not three, as reported by minutes, and then flew off toward Trinidad (FEH, ffrench [1973 , 1991 ]; M. Levinepers. comm.). Ob­ NAT; photograph deposited with TTRBC). served, but no details reported, by G. D. Smooker at Shiny Cowbird (Molothrus bonariensis).- Oc­ Gaspar Grande on 19 Nov 1921 (Belcher and curs primarily at forest edges. No brood parasite Smooker 1937b). Specimen: Monos (AMNH). host species yet detennined for the Bocas Islands. Faunal composition .-Thus far 135 species of Yellow Oriole (Icterus nigrogularis).-Breed­ birds have been reliably reported from the Bocas ing: At Chacachacare, an occupied nest was repor­ islands (see Species Accounts, Table 2). Of these, ted without details dming 28-30 May 1966 (ffrench at least 34 have been confirmed breeding, another 1967c), two fledglings were observed on 26 Jun 39 presumably breed, 32 likely represent non-breed­ 1997 (NAT, FEH), and an occupied nest was noted ing but locally resident (Venezuela or Trinidad) during 30 Aug to I Sep 1968 (ffrench 1969a). A pair visitors, 25 are Nearctic migrants, two are Neotropi­ was attending a nest at Huevos during 5-7 Jun 1965 cal migrants, two are introduced visitors and one is (ffrench 1967a). Specimens: Patos (COP). extirpated (former breeding status uncertain); an Crested Oropendola (Psarocolius decuman­ additional ten species are regarded as hypothetical us).-At Monos, several were heard calling on 9 Feb (see Species Accounts, Tables 2-3 ). All 135 species 1997 (FEH, IS) and seen on 7 Mar 1999 (IS). One of birds have been recorded from the major Bocas was seen flying along the south coast of Gaspar Islands. In contrast, only 31 have been recorded Grande on 27 Nov 1997 (FEH). No breeding colo­ thus far from the minor Bocas Islands (Table 3), nies, which are conspicuous, have yet been found. although this may be expected to increase with Yellow-fronted Canary (Serinus mozambic­ further field work. us).-A singing individual, obviously representing As expected, the largest islands contain the an escaped cagebird (presumably from Trinidad), most species, with 105 (61 presumably resident was carefully studied at the lighthouse on Chaca­ landbirds) recorded for Chacachacare, 87 (58) for chacare on 16 Aug 2000 (FEH, MK, BS). Monos, 60 (47) for Huevos, 66 (49) for Gaspar Gran­ Red Siskin (Carduelis cucullata).-Extirpated; de, and 43 (33) for more isolated Patos. An analysis it remains uncertain whether this species was a of the factors affecting species richness and den- 80 HAYES AND SAMAD

TABLE 3. Avifauna of the minor Bocas Islands. Islands (from west to east): ILG = Islotes Las Garzas; LIS = LaTsleta; GAS=Gasparillo; CRO=Cronstadt; ROC = Rock; LEN=Lenagan; NEL = Nelson; CRA = Craig; CAL = Caledonia; PEL= Pelican. The birds of Carrera have not been surveyed. Status: BR = breeding resident confirmed; B? = breeding resident suspected; RV =non-breeding but locally resident (e.g., Trinidad) visitor; NA = Nearctic migrant; NT= Neotropical migrant. For each island:+= recorded; - = not recorded; * = breeding confirmed.

Species Status ILG LIS GAS CRO ROC LEN NEL CRA CAL PEL Brown Pelican B? + + + + + + Magnificent Frigatebird B? + + + + I31ack Vulture BR +* + + +* + + Osprey NA + + Common I31ack-Hawk B'? + Yellow-headed Caracara RV + Rufous-necked Wood-Rail B? + Spotted Sandpiper NA + Semipalmated Sandpiper NA + Laughing Gull RV + + + Common Tern NA + + + Ruddy Ground-Dove B? + White-tipped Dove B? + + + + + Orange-winged Parrot RV + Tropical Screech-Owl B? + Short- tailed Swift BR + +* + + Blue-tailed Emerald" B? + + Copper-rumped Hummingbird B? + + + Yellow-bellied Elaenia B? + + + + + + Brown-crested Flycatcher B? + Great Kiskadcc B? + + Tropical Kingbird B? + Gray-breasted Martin B? + Barn Swallow NA + Tropical Mockingbird B? + + +* + + + Bananaquit B? + + + + Blue-gray Tanager B? + + + + + + + Red-legged Honeycreeper RV + Blue-black Grassquitb B? + Ruddy-breasted Seedeater B? + Yellow Oriole BR +* + •reported as a White-chested Emerald (Amazilia chionopectus), but most likely a female Blue-tailed Emerald; the former is unrecorded in the Bocas Islands and the latter is uncommon and was subsequently seen on Caledonia (FEH) bBlack-faced Grassquit also reported, but most likely Blue-black Grassquit; the former is unrecorded between Huevos and Tobago and the latter was subsequently seen on Nelson (FEH) sity overcompensation of birds in the Bocas Is­ Bocas Islands and small islets off the north coast of lands will be presented elsewhere (Hayes in prep.). Huevos and Monos (see Species Accounts). The Seabirds are relatively scarce, presumably due presence of snakes (see Murphy 1997, Lall and to the lack of adequate nesting and foraging habit­ Hayes 1999) and hawks may deter seabirds from at. No seabirds are known to breed on any of the nesting on the major Bocas Islands. major Bocas Islands, but the Brown Pelican and Coastal waterbirds are also scarce, with none Magnificent Frigatebird may breed on the minor !mown to breed on the islands. There are few mud- Avifauna of the Bocas Islands 81

TABLE 4. Number of bird species breeding during different months of the year in the Bocas Islands.

Evidence of 13reeding Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Eggs 0 0 0 0 6 3 0 2 0 0 0 Nestlings l 0 0 5 I 0 I 0 2 l 0 Fledglings 0 0 0 I 3 0 5 4 0 0 0 No details 0 0 10 2 3 2 0 0 Number of species breeding l 20 8 1 11 6 3 0 Days of field work 9 ) ] 13 3 17 5 0 27 12 24 13 flats or beaches to attract wading birds or shore­ those restricted to the Bocas Islands and north­ birds. The hypersaline Salt Pond of south em Cha­ western Trinidad. Three species are restricted to cachacare hosts a variety of invertebrate or­ the western Bocas Islands and are absent in ganisms (Bacon 1967), but apparently attracts few Trinidad: Red-crowned Woodpecker, Black-faced waterbirds; only a few individuals of Little Blue Grassquit and White-fringed Antwren. Enigmatical­ Heron (once), Rufous-necked Wood-Rail (once), ly, each of these species is common on Tobago Greater Yellowlegs, Lesser Yellowlegs, Spotted (ffrench 1991 ), which must have passed close to the Sandpiper (regular) and Northern Waterthrush (reg­ north coast of Venezuela as it was transported east­ ular) have been recorded during numerous visits. ward to its present position (e.g., Comeau 1991). Scavengers and raptors are surprisingly nu­ Five species are restricted to the Bocas Islands and merous. Vultures presumably forage primarily in northwestern Trinidad, suggesting that the islands Ve11ezuela and Trinidad, and nest or roost on the may have served as stepping stones during rela­ Bocas Islands. Hawks are apparently supported by tively recent dispersal events to Trinidad: Rufous sustainable populations of crabs, lizards, snakes Nightjar, Blue-tailed Emerald, Mouse-colored Ty­ and birds. rannulet, Streaked Saltator and Red Siskin (ffrench The landbird fauna is dominated by forest 1991). interior species tolerant of relatively arid vege­ Observations of overwater dispersal between tation. Several species are restricted to more open Venezuela and the islands are rare for locally resi­ l1abitats such as forest/grassland edges and the dent landbirds. Nevertheless, direct and indirect larger clearings (e.g., Common Ground-Dove, Yel­ evidence suggests that certain species may oc­ low-bellied Elaenia, the seedeaters). casionally or even routinely traverse between the Distributional patterns .-Because most spe­ Paria Peninsula of Venezuela and the Chaguaramas cies of resident birds are geographically wide­ Peninsula of Trinidad. A Gray Hawk was once ob­ spread, their source of origin is obscure. Presu­ served in a Questar telescope flying from Venezuela mably populations of many species were present over Chacachacare and on toward Trinidad (W. L. when the islands became isolated from the main­ Murphy pers. comm.), indicating that large raptors land. Some populations may have been augmented may routinely disperse between the continent and by immigrants from the Paria Peninsula of Ven­ adjacent Trinidad. Similarly, a flock of parrotlets ezuela or from Trinidad, whereas others likely be­ (Touit sp.) was once seen flying eastward high came extirpated through random population fluc­ over Chacachacare (ffrench 1969a), suggesting a tuations, natural disturbances (e.g., drought, fires non·stop flight between Venezuela and Trinidad or hurricanes) or human alteration of habitat (e.g., (no Touit sp. has been observed in trees on the deforestation). Some extirpated species may have Bocas Islands). The highly seasonal occurrence of recolonized the islands, particularly on the smaller the Red-eyed Vireo provides evidence that it all­ islands where faunal tumover is probably higher nually disperses across water in large numbers. The (e.g., Temple 1996). rare occurrences of obviously non-breeding birds The proximity of the Pmia Peni11sula makes it a on Chacachacare, located nearly halfway between likely source for many resident species, particularly Venezuela and Trinidad, provide indirect evidence 82 HAYES AND SAMAD that the Gray-headed Kite, Hook-billed Kite, main fairly pristine whereas others, such as Chaca­ Smooth-billed Ani, Tufted Coquette, Golden­ chacare, are gradually reverting back to their natur­ rumped Euphonia and Carib Grackle occasionally al condition. However, developers and conser­ disperse between Venezuela and Trinidad. vationists are currently battling over the future of Evidence for overwater dispersal by locally the islands belonging to T1inidad and Tobago. resident landbirds is more readily available for the Investors recently proposed to develop a gambling islands close to Trinidad. Orange-winged Parrots casino on Chacachacare, which would negatively have been noted flying from Trinidad to Gaspar impact the region's environment. Conservationists Grande (FEH); their apparent rarity from the Paria recently proposed to preserve Chacachacare and Peninsula (none seen during 1988 and 1999 expe­ the Chaguaramas Peninsula of Trinidad as a nation­ ditions; Bond eta!. 1989, FEH eta!.) suggests that al park. Trinidad is the source for birds wandering as far The Bocas Islands and the Chaguaramas Pen­ west as Chacachacare. A variety of birds observed insula of Trinidad provide the best examples of on Monos and Gaspar Grande, such as the White­ deciduous seasonal forest in Trinidad and Tobago, bearded Manakin (no known leks, which are con­ with a unique flora and fauna. This study docu­ spicuous) and Crested Oropendola (no known ments the current status of the avifauna of the nesting colonies, which are conspicuous), almost Bocas Islands, which presently does not include cetiainly represent strays from nearby Trinidad. any globally threatened species. However, the The Yellow-headed Caracara, Tropical Kingbird and globally threatened Red Siskin once occurred on Palm Tanager have been observed flying between the islands and a reintroduction programme has Trinidad and Gasparillo. been proposed (J. C. Eitniear pers. comm.). Further Similar observations of landbirds obviously studies of the status of plants and animals are dispersing between Venezuela and Trinidad have urgently needed to determine which species may be been recorded from tiny Soldado Rock, which threatened if developers succeed and what steps cannot support breeding populations of such birds, may be taken to mitigate the consequences of in the southern Gulf ofParia (ffrench 1990). Further development. observations of overwater dispersal, which could be facilitated by an ambitious banding project, may ACKJ\OWLEDGEMENTS enable us to better understand the factors affecting turnover rates of birds among the Bocas Islands as We thank the following observers who con­ well as the migration patterns of landbirds that tributed observatiollS for this study: P.R. Bacon, S. regularly migrate between South America and Bodnar, E. Carrington, G. C. Cuffy, W. Diaz, W. G. Trinidad (ffrench 2000). Downs, M. ffrench, R. P. ffrench, G. Gomes, C. S. Breeding season.-Based on observations of Griffiths, B. D. Hayes, W. K. Hayes, V. L. Joseph, nests and fledglings, the breeding season for most M. Kenefick, J. S. Kenny, N. K. Klein, J. M. Koos, species on the Bocas Islands appears to be re­ G. Lalsingh, V. Maharajh, D. B. McNair, W. L. stricted to the early wet season, from May to Sep Murphy, H. Nelson, F. Razac, C. Rooks, B. Sanasie, (Table 4). In contrast, many species breed through­ G. Seutin, D. W. Snow, J. Teixeira, N. A. Trimm and out the year in Ttinidad and Tobago, although G. White. For reviewing earlier versions of this breeding generally peaks during the early wet sea­ manusctipt we thank C. Chariandy, C. T. Collins, J. son (Snow and Snow 1964, ffrench and ffrench C. Eitniear, R. ffrench, W. L. Murphy and S. A. 1979). Apparently insufficient food resources are Temple. Funds for our expeditions to the Bocas available during the dry season in the Bocas Is­ Islands were provided directly or indirectly by the lands to support reproductive activities for most British Broadcasting Corporation (to C. K. Starr and species ofbirds. IS), Caribbean Union College (biology labs, to Conservation.-Aithough most of the Bocas FEH), Center for the Study of Tropical Birds (grant Islands have been significantly altered by human to FEH and IS), Field Museum of Natural History activity dming the past two centuties, several re- (grant to N. K. Klein), Sigma Xi (grant to M. V. Avifauna of the Bocas Islands 83

Bernard), University of Florida at Fort Lauderdale BOND, R.,P. COVEY,C.SHARPE,ANDA. VAREY. 1989. (to V. Maharajh), University of Wisconsin (grant to Cambridge Columbus Zoological Expedition to N. K. Klein), and University of the West Indies Venezuela 1988. Unpubl. rept. (zoology labs and grant to FEH). Field work by G. CARMICHAEL, G. 1961. The history of the West Indi­ Seutin was funded by the National Geographic an islands of Trinidad and Tobago 1498-1900. Society(grantto R. E. Ricklefs). The Coast Guard of Alvin Redman, London. 463 pp. Trinidad and Tobago provided transportation and CHABOO, C. 1990. The vegetation of the Five Is­ logistical support for several UWI trips to Chaca­ lands, T1inidad, W. I. Living World (J. Trin. chacare. R. C. Boos permitted access to Huevos. J. Tab. Field Nat. Club) 1989-90:10-11. M. Bates provided a pertinent reference. M. Levine CHALMERS, W. S. 1965. The vegetation of Grand clmified the status of Red Siskin specimens in the Fond, Monos. J. Trin. Field Nat. Club 1965:10- American MLtseum of Natural History. Finally, we 10-15. thank several faculty members and many students CHAPMAN, F. M. 1894. On the birds of the island of from CUC and UWI, plus several colleagues, who Trinidad. Bull. A mer. Mus. Nat. Hi st. 6:1-86. accompanied us on field trips. COMEAU, P. L. 1991. Geological events influencing natural vegetati011 in Trinidad. Living World (J. LITERATURE CITED Trin. Tob. Field Nat. Club) 1991-1992:29-38. DARLINGTON, J. 1967. The vegetation ofChacacha­ A MERTC.A.N ORNITHOLOGISTS' UNION. 1998. Checklist care Island. Ttin. Field Nat. Club J. 1967:29-40. of North American birds. 7th ed. American DE VERTEUIL, A. I 993. Scientific sorties. Litho Ornithologists' Union, Washington, D. C. 829 Press, Port of Spain. pp. FFRENCH, R. P. I 965a. Notes on the avifauna of ANON. 1971. Atlantic Coast tern watch. Ttin. Field Grand Fond, Monos, May I 964. J. Trin. Field Nat. Club J. 1971 :38. Nat. Club 1965:28-36. BACON, P. R. 1967. The salt pond, Chacachacare FFRENCH, R. P. 1965b. Check-list of the birds of Island. Trin. Field Nat. Club J. 1967:41-44. Grand Fond VaHey and Bay. J. Trin. Field Nat. BARR, K. H. 1981. Geological outline. Pp. 13-22 in Club 1965:37-39. The natural resources of Trinidad and Tobago FFRENCH, R. P. 1965c. Notes on the avifauna of (St. G. C. Cooper and P. R. Bacon, eds.). Ed­ Grand Fond, Monos, Aug 1964. J. Trin. Field ward Arnold (Publishers) Ltd., London. Nat. Club 1965:41-50. BEARD, J. S. 1946. The natural vegetation of FFRENCH, R. P. 1967a. The avifauna of Huevos Trinidad. Oxford For. Mem. 20:1-152. Island. Trin. Field Nat. Club J. 1967:19-24. BELCHER, C., AND G. D. SMOOKER. 1936a. Birds of !'FRENCH, R. P. I967b. Checklist of the birds of the Colony of Trinidad and Tobago.-Part III. Huevos and Chacachacare. Trin. Field Nat. Ibis 1936:1-35. Club J. 1967:25-27. BELCHER, C., AND G. D. SMOOKER. 1936b. Birds of FFRENCH, R. P. !967c. The avifauna of Chacacha­ the Colony of Trinidad and Tobago.-Part IV. care Island. Trin. Field Nat. Club J. 1967:45-52. Ibis 1936:792-813. FFRENCH, R. P. 1969a. Further notes on the avifauna BELCHER, C., AND G. D. SMOOKER. 1937a. Birds of ofChacachacare Island. Trin. Field Nat. Club J. the Colony of Trinidad and Tobago.-Part V. 1969:10-12. Ibis 1937:225-249. fFRENCH, R. P. 1969b. The avifauna of Saut D'Eau BELCHER, C., AND G. D. SMOOKER. 1937b. Birds of Island. Trin. Field Nat. Club J. 1969:16. the Colony of Trinidad and Tobago.-Part VI. FFRENCH, R. 1973. A guide to the birds of Trinidad Ibis 1937:505-550. and Tobago. Livingston Publishing Company, BERRIDGE, C. E. 1981. Climate. Pp. 2-12 in The Wynnewood, Pennsylvania. 470 pp. natural resources of Trinidad and Tobago (St. FFRENCH, R. 1990. The birds and other vertebrates G. C. Cooper and P.R. Bacon, eds.). Edward of Soldado Rock, Trinidad. Living World (J. Arnold (Publishers) Ltd., London. Trin. Tab. Field Nat. Club) 1989-1990:16-20. 84 HAYES AND SA.\1AD

FFRENCH, R. 1991 . A guide to the birds of Trinidad KUGLER, M. G. 1953. Jurassic to recent sedimentary and Tobago. 2nd ed. Cornell University Press, environments in Trinidad. Bull. Ass. Suisse Ithaca, New York. 426 pp. des Gel. & Ing. du Petro1e 20(59):27-60. FFRENCH, R. 2000. Possible intra-regional bird mi­ LALL, S.A.,ANDF.E.HAYES. 1999. Observations on gration in Trinidad a11d Tobago. Living World the reptiles and mammals of Chacachacare, (J. Trin. Tob. Field Nat. Club) 1999-2000:27-31 . Bocas Islands, with notes on six species new FFRENCH, R., AND M. FFRENCH. 1979. The birds of to the island. Living World (J. Trin. Tob. Field Grafton Estate, Tobago. Living World (J. Trin. Nat. Club) 1999:in press. To b. Field Nat. Club) 1978-1979: I 9-24. MANUEL, R. L. 1965. Monos Island studies (mos­ FFRENCH, R. P., AND F. E. HAYES. 1998. Rare bird quitoes, reptiles, bats, bromeliads, orchids). J. records from Trinidad & Tobago in 1997. Co­ Trin. Field Nat. Club 1965:16-24. tinga 9:84-85. MANUEL, R. L. 1967. Huevos Island survey report HAYES, F. E. 1995. Definitions for migrant birds: (mosquitoes, bromeliads, orchids and bats). what is a Neotropical migrant? Auk 112 :521- Trin. Field Nat. Club J. 1967:12-14. 523. MARSHALL, R. C. 1934. The physiography and HAYES, F. E. 2001 . First sight records ofSwainson's vegetation ofTrinidad and Tobago. Clarendon Hawk (Buteo swainsoni) for Trinidad and Cha­ Press, Oxford, UK. cachacare Island, with comments on its status MEYER DE SCHAUENSEE, R. M., AND W. H. PHELP S, and trans-Caribbean migration. Pitine 14: 63-65. JR. 1978. A Guide to the Birds of Venezuela. HAYES, F. E., C. L. RAM.JOHN, AND F. B. LUCAS. 1998. Princeton University Press, Princeton. 424 pp. Checklist of the birds of proposed Matura Na­ PHELPS, W. H., AND W. H. PHELPS, JR. 1958. Las tional Park and adjacent areas in northeastern aves de Ia isla de Patos con algunos docu­ Trinidad. Department of Life Sciences, Uni­ mentos sobre Ia historia y la geologia de Ia isla. versity of the West Indies, St. Augustine, Bol. Soc. Ven. Cs. Nat. 92:105-133. Trinidad and Tobago. 6 pp. PrERCE, G. R. 1958. Geology of Patos Island, State HERKLOTS, G. A. C . 1961 . The birds ofTrinidad and of Sucre. Bol. Soc. Ven. Cs. Nat. 92:122-123. Tobago. Collins, London. 287 pp. RAMDIAL, B.S. 1972. Kronstadt Island. Pp. 54-58 in IMBRIE, J., AND K. P. IMBRIE. 1976. Ice ages. Enslow The wildlife sanctuaries of Trinidad and To­ Publishers, Short Hills, New Jersey. 224 pp. bago (P.R. Bacon and R. P. ffrench, eds.). Min­ JOSEPH, E. L. 183 8. History of Trinidad. A. K. istry of Agriculture, La11ds and Fisheries, Pmt Newman and Co. Ltd. (reprinted 1970 by Frank of Spain, Trinidad. Cass & Co., London). 272 pp. RETOUT, M. T. 1988. Called to serve. A history of JUNGE, G.C.A., ANDG.F.MEES. 1958. The avifauna the Dominican sisters in Trinidad and Tobago ofTrinidad and Tobago. Zool. Verhand. 37:1- 1868-1988. Pari a Publishing Co., PortofSpain, 172. Trinidad. 184 pp. KARR, J. R . 1981. Surveying birds with mist nets. RIDGELY, R., AND G. TUDOR. 1994. The birds of Stud. Avian Bioi. 6:62-67. South America. Vo I. II. The suboscine pas­ KELSHALL, G. T. M. I 988. The U-boat war in the serines. University of Texas Press, Austin, Caribbean. Pari a Publishing Co., Port of Spain, Texas. 814 pp. Trinidad. 496 pp. SNOW, D. W. 1962a. Notes on the biology of Trin­ KENNY, J. S. 1995. Views from the bridge: a memoir idad swifts. Zoologica 47:129-139. of the freshwater fishes of Trinidad. Trinprint SNOW, D. W. 1962b. The natural history of the Limited, Barataria, Trinidad and Tobago. 98 pp. oilbird, Steatornis caripensis , in Trinidad, W. KENNY, J. S., AND P. R. B ACON. 1981. Aquatic re­ I. Part 2. Population, breeding ecology and sources. Pp. 112-1 44 in The Natural Resources food. Zoologica 47:199-221 . of Trinidad and Tobago (St. G . C. Cooper and SNOW, D. W., AND B. K. SNOW. 1963. Weights and P.R. Bacon, eds.). Edward Arnold (Publishers) wing-lengths of some Trinidad birds. Zoolo­ Ltd., London. gica 48:1-12. Avifauna of the Bocas Islands 85

SNOW, D. W., AND B. K. SNOW. 1964. Breeding Tob. Field Nat. Club) 1995-1996:22-26. seasons and annual cycles of Trinidad land WUNDERLE, J. M. , JR. 1994. Census methods for birds. Zoologica 49:1-39. Caribbean land birds. U. S. Dept. Agr. For. TEMPLE, S. A. 1996. Distributional ecology of Serv., S. For. Exp. Sta., Gen. Tech. Rep. S0- selected plants and animals on T1inidad's Five 98:1-26. Islands archipelago. Living World (J. Trin. Pp. 86-103 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Uni v. West Indies, St. Augustine, Occ. Pap. 11, 2002.

GROUND-BASED NEARCTIC-NEOTROPIC LANDBIRD MIGRATION DURING AUTUMN IN THE EASTERN CARIBBEAN

1 2 3 DOUGLAS B. MCNATR , FRED SIBLEY , EDWARD B. MASSJAH , AND MARTIN D. FRosr 1 Tall Timbers Research Station, 13093 Henry Beadel Drive, Tallahassee, FL 32312-0918, USA 2The Conservation Agency, 6 Swinburne Street, Jamestown, Rl 02835, USA 3c/o Dr. Nelson, Johnson Road, Fitts Village, St. James, Barbados 4Featherbed Lane, St. John, Barbados

ADSTRACT.-We examined ground-based Nearctic-Neotropic landbird migration during autumn at coastal sites on two islands about 775 km apart in the eastern Caribbean, where autumn migration had not been previously studied using mist-nets. We sampled migrants using mist-nets at Harrison Point (HP), Barbados, for 42 days in 1997 and 31 days in 1998-1999, and at Guana Island (Gl), British Virgin Islands, for 52 days during 1995-1999. We also obtained information on landbird migration from sight observations. We recorded 28 species of Nearctic-Neotropic landbird migrants at HP and 23 species at GI, for a total of 36 species. The volume of migration was low at both sites. The Blackpoll Warbler (Dendroica striata) was the most abundant migrant (98 captures, 206 observations at HP; 132 captures, 263 observations at GI). The Yellow­ billed Cuckoo (Coccyzus americanus) was the second most abundant migrant at HP (six captures, 101 observations), but was rare at Gl (seven observations). The Red-eyed Vireo (Vireo o. olivaceus), previously considered a vagrant or scarce transient in the eastern Caribbean, was the third most abundant nocturnal migrant at HP (12 captures, 8 observations). At HP and Gl, respectively, 23% and 33% of captured Blackpoll Warblers were after hatching year birds, compared to 8% and 14% for other Nearctic­ Neotropic migrants. At both sites we recorded many scarce transients or apparent vagrants, some verified or seen for the first time in the eastem Caribbean. All species recorded except Northern Rough-winged Swallow (Stelgidopteryx serripennis) at HP and Nashville Warbler (Vermivora rujicapilla) at GI, have been recorded at least once during winter in South America; however, more species wintering primarily within the West Indies occurred at GI. Autumn migration of Nearctic-Neotropic landbirds is a regular phenomenon to the eastern Caribbean for a few relatively abundant species moving to their winter range in South Ametica, and also includes a large variety of scarce species. Other than Blackpoll Warblers, which migrate during autumn over the western North Atlantic Ocean through the West Indies to South America, the other Nearctic-Neotropic landbird migrants probably departed from southeastern North America for a shorter over-water crossing through the Greater Antilles and over the Caribbean Sea.

RESUMEN.-Se estudio Ia migraci611 por tierra del nea1iico al neotr6pico de aves terestres durante el otofio en sitios costeros de dos islas separadas aproximadamente 775 km Ia una de la otra en el este del Caribe, donde no se ha estudiado previamente Ia migraci6n de otoiio us ando redes de neblina. Se muestrearon migratorios usando redes

86 Nearctic-Neotropic Landbird Migration 87

de neblina en Harrison Point (HP), Barbados, por42 dias en 1997 y31 dias en 1998-1999, yen Isla Guana (I G), Islas Virgenes de Inglaterra, par 52 dias durante 1995-1999. Tam bien se obtuvo informacion sobre Ia migraci6n de aves terrestres por observaciones visuales. Se registraron 28 especies de aves migratorias terrestres neartico-neotr6pico en HP y 23 especies en IG, para un total de 36 especies. El volumen de migraci6n fue bajo en ambos sitios. La Reinita Rayada (Dendroica striata) fue el migratorio mas abundante (98 capturas, 206 observaciones en HP; 132 capturas, 263 observaciones en IG). El Cuclillo Pico Amarillo (Coccyzus americanus) fue el segundo migratorio mas abundante en HP (seis capturas, 101 observaciones), pero fue raro en IG (siete observaciones). El Julian Chivi Ojirrojo (Vireo o. olivaceus), previamente considerado vagante o escaso, fue e] tercermigratorio noctumo mas abundante e11 HP (12 capturas, 8 observaciones). En HP y GI, respectivamente, 23% y 33% de las capturas de Reinita Rayada fueron de aves de mas de un afio de edad, comparados con 8% y 14% de otros migratorios neartico-neotr6- pico. En ambos sitios se registraron muchos transeuntes escasos o vagantes aparentes, algunos documentados u observados por primera vez en el este del Caribe. Todas las especies registradas, salvo Ia Golond1ina Ala de Sierra (Stelgidopteryx serripennis) en HP y Ia Reinita de Nashville (Vermivora ruficapilla) en IG, han sido registradas par lo menos una vez durante el inviemo del norte en Sudamerica; sin embargo, en IG se regis­ traron mas especies que inveman p1incipalmente dentro de las lndias Occidentales. La migraci6n de otofio neartico-neotropico de las aves tenestres es un fen6mino regular en el este del Caribe para las especies relativamente abundantes que migran bacia su area de invemada en Sudamerica, y tam bien incluye una amplia variedad de especies escasas. Ademas de las Reinitas Rayadas, que migran durante el otoi'io sobre el Noroeste Atlantica por las Indias Occidentales basta Sudamerica, las otras especies migratorias terrestres neartico-neotr6pico probablemente parten del sudeste de Norteamerica realizando un cruce mas corto sobre el Mar del Caribe por las Antillas Mayores.

KEY WORDS.- abundance, age, autumn migration, Barbados, Cmibbean Sea, Coccyzus americanus, Dendroica striata, landbirds, migratory routes, Nearctic-Neo­ tropic migrants, vagrants, Vireo o. olivaceus, Virgin Islands

Radar-based observations from Pue11o Rico relatively large number of species and generally low and several locations in the Lesser Antilles (Anti­ numbers of individuals of Nearctic-Neotropic mi­ gua, Barbados), aided by visual confirmation of grants during autumn, with a broad peak of occur­ species identification, documented that large num­ rence in October and early November. Norton bers of small landbirds, including Blackpoll War­ {1981 ), Norton eta!. (I 989), Keith (1997), Steadman blers (Dendroica striata), fly over these regions et al. (1997) and Feldmann et al. (1999) cited few during autumn migration (Hilditch et al. 1973, observations of Nearctic-Neotropic landbirds dur­ Williamsetal.1974, 1977a,b, 1978,Richardson1976, ing autumn migration in the British Virgin Islands, 1980, Williams and Wi !Iiams 1978a,b, Larkin et al. St. Lucia, St. Kitts, and Guadeloupe and Martin­ 1979, Williams 1985, Nisbet et al. 1995), although ique. Although the Virgin Islands (at the eastern tl1e density of Jandbirds east of Puerto Rico is much end of the Greater Antilles) has a fair number of less (Richardson 1976). Sight observation data overwintering Nearctic-Neotropic landbirds com­ obtained over many years from Antigua and Bar­ pared to the Lesser Antilles (Robertson 1962, Pash­ bados, where observer effort has been relatively ley 1988, Wunderle and Waide 1993), the general high for the Lesse: Antilles (Holland and Williams scarcity of overwintering Nearctic-Neotropic land­ 1978; Hutt et al. in prep.), have documented a birds in the eastern Caribbean, especially in the 88 McNAIR ET AL. southern Lesser Antilles (Terborgh and Faaborg above sea level. The mean annual rainfall is 110-125 1980, Wunderle and Waide 1993, Keith 1997), has em; surface water is absent. The vegetative cover reinforced the perception that grounded migrants is highly disturbed coastal scrub, thickets and during autumn are sporadic and scarce here. The woodlots, which now surround an abandoned low number of grounded Nearctic-Neotropic land­ sugar cane plantation house. Naturalised species bird migrants east of Puetto Rico is 11ot concordant are numerous, especially quick stick (Gliricidia with the large volume documented by radar data. sepium), casuarina (Casuarina equisetifolia), clam­ Nearctic-Neotropic landbird migration has not my cheery (Cordia obliqua) and Pride of India been investigated using mist-nets in the eastern {Tamarindus indica), although the native white­ Caribbean, except documentation of new and rare wood (Tabebuia pal/ida) is one of three dominant species of Nearctic-Neotropic landbird migrants trees. Other native trees or shrubs which are during autumn !997 at Barbados (McNair et al. numerous include bread-and-cheese (Pithecello­ 1999). Previous studies using mist-nets to sample bium unguis-cati), dog wood (Capparisjlexuosa), populations ofNearctic-Neotropic landbirds in the sage (Lantana spp.), black sage (Cordia curas­ West Indies have concentrated on wintering birds savica) and coffee fence (Clerodendrum aculeat­ (Wunderle and Waide 1993, Wallace et al. 1996, um). HP is about 16 ha, excluding adjacent sugar Wallace et al. 1999, and references cited therein). cane fields. We operated mist-net stations during autumn along Guana Island (18 o30'N, 64 o30'W), 340 ha, is the coast of two island sites about 775 km apart in located in the British Virgin Islands just northeast the eastern Caribbean, at Harrison Point (hereafter of Tortola Island. The British Virgin Islands are HP), Barbados, and Guana Island (hereafter Gl), about 130 km north-northwest of Anguilla, the British Virgin Islands. Our sampling periods were northernmost large island of the Lesser Antilles. primarily restricted to October to coincide with the The mean annual rainfall is 102 em. Freshwater on Bl ackpo 11 Warbler migration (see Nisbet 1970, Pash­ GI is scarce and restricted to a small seasonal seep ley and Hamilton 1990, Nisbet et al. 1995). (other than pools associated with a hotel). A large The primary purpose of our combined efforts salt pond is present. The vegetative cover is pri­ was to obtain samples of patterns ofNearctic-Neo­ marily open xerophytic forest with more than 40 na­ tropic landbird migration in the eastern Caribbean. tive tree species, plus artificially maintained grassy We use this information to address which of two fields and some ornamental vegetation around the migratory routes these species take during autumn only hotel. The forest is recovering from over­ to reach the eastern Caribbean. Birds may fly from grazing by sheep that ended about 10 yr ago . northeastern North America over the western North Native trees and shrubs include the frequent dom­ Atlantic Ocean through the West Indies to South inant tabebuia (T. heterophylla), gumbo-limbo America (Blackpo11 Warbler: Nisbet 1970, Hilditch et (Bursera simaruba), loblolly (Pisonia subcordata), al.1973, Williamsetal.l974, 1977b, 1978,Richard­ frangipani (Plumeria alba), buttonwood (Cono­ son 1976, 1980, Williams and Williams 1978a, Larkin carpus erectus), acacia (Acacia muricata) and sea et al. 1979, Williams 1985, McNair and Post 1993, grape ( Coccoloba uvifera; Lazell1996). Naturalised Nisbet et al. 1995) or may depart from southeastern species, which are not an important component of North America for a sh01ter over-water crossi11g the vegetation, include coconut (Cocos nucifera), through the Greater Antilles and over the Carib­ royal poinciana (Delonix regia) and tamarind (Tam­ bean Sea (Richardson 1976, 1980; also see route orinda indica). number three in Rappole et al. 1979). Sampling methods.-In 1997, McNair, Massiah and Frost monitored 16 30-mm mist-nets atHP from STUDY AREAS AND METHODS 29 September to 9 November (42 days) for a total of 5,909 net hours. Nets were usually operated from Study areas.-Harrison Point (13 o J9'N, 59 o sunrise to sunset, although occasionally closed 1-2 39'W) is located at the northwest tip of Barbados hours before sunset. We temporarily closed the on a raised coral limestone terrace about 30 m nets for a few hours on some days because of Nearctic-Neotropic Landbird Migration 89 inclement weather, but did not miss a single day of 0-3 , Manomet Bird Observatory [a trace of fat was sampling. We placed half of the mist-nets in fairly scored as 0.5]). Birds were aged and sexed when open forest (mean score of 60% for canopy den­ possible by skull ossification and plumage charac­ sity; James and Shugart 1970) dominated by quick ters following Pyle et al. (1987, 1997). A small pro­ stick. The other eight nets were placed in fairly portion (<5%) ofHY Blackpoll Warblers from mid­ closed mixed forest (mean score of75% for canopy October onward had fully ossified skulls, so these density) where whitewood was usually the domi­ individuals were aged solely by plumage characters nant tree, along with a variety of naturalised and including the non-singular use of pointedness of native species. Casuarinas emerged above the can­ the rectrices. opy in mixed habitat in more than half of the net We assessed the abundance of birds at each lanes, to 13.3-17 m. Otherwise, the mean heights of site by calculating the number of daily captures and the vegetation in the 'whitewood' net lanes was estimated sight observations for each species and still higher than in the 'quick stick' lanes (7.5-9.5 m summed these totals for each category over the vs. 5.5-6.0 m). In 1998-1999, Massiah and Frost year or years. Observations of banded birds were monitored 8-12 mist-nets and operated nets on an excluded from the sight observation totals. Sight intermittent basis from 26 September to 8 November observations may include dupllcate data, so we (31 days) for a total of 1,333 net hours. We usually estimated these numbers conservatively for the opened the nets in the morning; the nets were most numerous species. We assessed the frequen­ always open at midday (4-8 hours post-sunrise), cy of birds at each site by calculating the number of but rarely later. We also used sight observation days each species was recorded, based on both data obtained during autumn migration from 1993- captured birds and sight observations. 1999 (excluding 1997, 52 days) to augment our We calculated migratory volume at both sites results from mist-netting. using capture rates from mist-net sampling only, Sibley and associates operated 2-12 30/36 mm although we recognise that we did not use stan­ mist-nets at Gl during October for 5 yr (1995-1999; ardised procedures at GI. Yellow-billed Cuckoos 52 days) for a total of 1,869 net hours. 1l1e length of were excluded from this analysis because they were our visits each year varied from 1-3 weeks. Uu1ike not adequately sampled by the small mesh sizes HP, where mist-net operations were standardised, that we used. Indigo Buntings (Passerina cyanea) we frequently moved nets at GI in attempts to in­ at HP were also excluded from this analysis be­ crease capture rates ofNearctic-Neotropic migra11ts cause we captured these birds 5-7 days after their and closed or failed to open nets during unpro­ arrival by moving one mist-uet to a favoured lo­ ductive pe1iods. We placed the nets at many lo­ cation and beating the birds in (McNair et al. 1999). cations (ridges, along trails) in the open forest We assessed the seasonal distribution of where mean height of the vegetation ranged from 5- Yellow-billed Cuckoo at HP in 1997 by combining 7 m, aud across hedgerows with nets extended to the number of daily captures and estimated sight the fields, roads or margin of the salt pond at one or observations to obtain a daily estimated total and both ends. We often operated the nets throughout then calculated the number of birds for 5-day peri­ daytime, but favoured morning hours. We also ods. Using the same method, we added this infor­ used sight observation data obtained during au­ mation to results from sight observations only from tumn migration from 1994-1999 (58 days) to aug­ 1993-1996 and 1998-1999, butadjustedforthenum­ ment our results from mist-netting. er of days each period was sampled since this was Data collection and analyses.-For all birds unequal. Our unit of measure is bird-day (for each captured in mist-nets, we recorded date of capture, 5-day period), as used by bird observatories in age (AHY =adult; HY = immature) and sex, flat­ Britain. We also assessed the seasonal distribution tened wing length (mm; at HP) or wing chord (mm; of Blackpoll Warbler, but this information will be at GI), mass (nearest 0.1 or 0.25 g, but nearest 0.5 g presented elsewhere (McNair et al. in prep.). for Yellow-billed Cuckoo [Coccyzus americanus]), We used chi-square analysis to compare dif­ and fat class (HP: 0-5, Foster and Cannelll990; GI: ferences iu the diurnal timing of migration for cap- 90 McNAIRETAL tured birds at HP in 1997 after adjusting the ex­ We estimated the rate of mass loss (g/hr) as a pected frequencies for minor differences in netting function of mass for each species from the empiric­ effmi among the three time periods used. We also ally-detived formula for small passerines (8-32 g) performed Chi-square analysis for sight obser­ during nocturnal flight (Hussell and Lambert 1980), vations, with a= 0.05. which estimates that mean mass loss is 0.91% of 040 We obtained information 011 estimated mean body mass/hr. This f01mula is Lw = 0.0533 W , fat-free masses, adjusted for age, sex, and wing where L =mass loss (g/hr) and W =mass. We as­ length category when possible (although informa­ sumed that mass loss only represents loss of met­ tion on wing length category is rarely available) for abolized adipose fat. We also used this formula for noch1mal Nearctic-Neotropic migrants from Connell our only medium-sized non-passerine (Yellow-billed et al. (1960), Odum in Dunning (1993) [which super­ Cuckoo). We used measured, not derived values of cedes Odum in Nisbet et al. (1963) for Blackpoll mean mass loss for four species (Swainson's Warbler], Rogers and Odum (1 964, 1966) and Child Thrush, Red-eyed Vireo, American Redstart, and (1969). Estimated mean fat-free masses used are: Ovenbird) in Russell and Lambert (1980). We used Yellow-billed Cuckoo, 46.8 g; Red-eyed Vireo (Vir­ the empirically derived value of mass loss (0.144 eo o. olivaceus), 14.59 g; Gray-cheeked Thrush g/hr) for Blackpoll Warbler, despite the perception (Catharns m. minimus), 25.2 g; Swainson's Thrush that Blackpolls may have lower fllght metabolism (C. ustulatus), 24.18 g; Northern Parula (Parula am­ costs than other passerines (Russell and Lambert ericana, 5.93 g; Chestnut-sided Warbler (D.pensyl­ 1980), as well as the estimated values of0.1 07 glhr vanica), 8.03 g; Magnolia Warbler (D. magnolia), and 0.07 g/hr (for birds of low mass; less than 13 .2 6.92 g; Black-throated Blue Warbler (D. caerul­ g) in Nisbet et al. ( 1963) since all three values are of escens), 7.64 g; Blackpo11 Warbler, I 0.34 g; Ameri­ similar magnitude (not 0.062 g!hr which pertains to can Redstart (Setophaga ruticilla), 6.49 g; Oven­ captured [resting] birds not undergoing migratory bird (Seiurus aurocapillus), 15.52 g; Nmihem fllght contra Hunt and Eliason [ 1999]). Then using Waterthrush (S. noveboracensis), 13.68 g; Ken­ mean fat loads for each species, we converted rates tucky Warbler (Oporornisfonnosus), 11 .36 g; Scar­ of mass loss to the estimated number of hours each let Tanager (Piranga olivacea), 24.13 g; and Indigo species could fly before reaching their fat-free mass Bunting, 12 .34 g. Using these values, we calculated and conve1ted this value to the estimated distance the mean percentage above fat-free mass for each each species could fly, using an average air speed of these species that we captured at either site. We of 38.5 km/hr for small passerines over the Lesser compared these calculated values at our two sites Antilles under conditions of no wind (Nisbet et al. to the mean percentage above fat-free mass of 1963, Williams et al. l977b, 1978, Williams and trans-Gulf migrants during spring (published mass Williams 1978a, Williams 1985, Pennycuick 1989). data are not available for arrival of trans-Gulf mig­ rants during autumn in the Yucatan peninsula; see RESULTS Winker 1995a) tl1at were captured at East Ship Island, a barrier island 14 km off the Mississippi Species composition and abundance.-We coast, following a long (approximately 1050 km) captured or observed 22 species of nocturnal over-water flight (Kuenzi et al. 1991 ); we also ob­ Nearctic-Neotropic landbird migrants at HP during tained information on the mean mass value of Gray­ 1993-1999 (Tables 1 and 2), plus six species of cheeked Thrushes that were not recaptured at a diurnal migrants (Chimney Swift [Chaetura pel­ coastal woodland chenier in Cameron Parish, Louis­ agica ], l1irundinids and Bobolinks [Dolichonyx ian a; Yong and Moore 1997). We used the same myzivorus]). At GI, we captured or observed 20 fat-free values as above in our calculations of the species of noctumallandbird migrants during 1994- mean percentage above fat-free mass for these 1999 (Table 1) , plus three species of diurnal mi­ trans-Gulf migrants except for Chestnut-sided War­ grants (himndinids and Bobolinks). At both sites bler (8.01 g), Scarlet Tanager (24.5 g), and Indigo combined, we recorded a total of 36 species. Bunting (11 .97 g for females, 12.69 g for males). The Blackpoll Warbler was the most abundant Nearctic-Neotropic Landbird Migration 91

TABLE 1. Number of birds captured in mist-nets and estimated number of birds observed, number of days recorded and range of dates for each species of Nearctic-Neotropic landbird migrant at Hanison Point, Barbados, from 29 September to 9 November 1997 (42 days), and at Guana Island, British Virgin Islands, in October 1995-1999 (52 days).

Harrison Point, Barbados Guana Island, British Virgin Islands Number Number Number Range Number Number Number Range Species' captured observed of days of dates captured observed of days of dates Nocturnal Migrants Coccyzus american us 6 45 30 2 Oct-8 Nov 7 5 14-25 Oct Contopus virens I sordidulus l l90ct Vireo jlavifrons 1 12 Oct Vireo o. olivaceus lO 5 12 5-23 Oct 6 6 14-21 Oct Catharos m. minimus I I 12 Oct Catharus ustulatus 19 Oct Vermivora chrysoptem I Nov 2 14-18 Oct Vermivora mficapilla l 13 Oct Parula americana 22 Oct 2 3 19-28 Oct Dendroica petechia 9 Nov Dendroica pensylvanica 8 Nov 2 2 18-26 Oct Dendroica mag;;J[ia 1 200ct Dendroica tigrina 2 7 16-22 Oct Dendroica caerulescens 2 2 4-22 Oct Dendroica discolor 10 4 4-14 Oct Dendroica striata 75 98 25 I Oct-9 Nov 132 263 49 3-30 Oct Mniotilta varia 5 7 9 6-28 Oct Setophaga ruticilla 2 2 13-15 Oct 1 I 26 Oct Seiurus aurocapillus 3 1 4 21-28 Oct Seiurus noveboracensis 5 13 16 5-29 Oct Oporomis formosus 2 2 2-4 Oct 1 20 Oct Oporornis agilis 1 1 Nov Piranga olivacea 4Nov Pheuctiws fudovicimzus 3 4 22 Oct-1 Nov 3 3 19-22 Oct Guiraca caerulea 1 8 Nov 2 2 10-12 Oct Passerina cyanea 9 9 l-9Nov 22 Oct Diurnal Migrants Tachycineta bicolor 21 Oct StelgidopteiJIX serripennis 1 6 Oct Riparia riparia 17 4 2-130ct Petrochelidon pyrrhonota 5 2 8-12 Oct Hinmdo rustica 47 9 2-!6 Oct 7 2 21-25 Oct Dolichonyx oryzivorus 154 26 29 Sep-29 Oct 5 2 12-22 Oct 'species names not mentioned in text include: Yellow-throated Vireo (Vireo flaviji·ons), Tree Swallow (Tachycineta bicolor), Bank Swallow (Riparia riparia), Cliff Swallow (Petrochelidon pyrrhonota), Yellow Warbler (Dendroica petechia; aestiva group), Prairie Warbler (Dendroica discolor), Black-and-white Warbler (Mniotilta varia), Rose- breasted Grosbeak (Pheucticus ludovicianus), and Blue Grosbeak (Guiraca caerulea)

migrant at both sites (Tables 1 and 2). Excluding similar except that the number of captured birds in Yellow-billed Cuckoos, Indigo Buntings, and diur­ 1998-1999 was lower. Excluding Yellow-billed Cuc­ nal migrants at HP, Blackpolls accounted for 78% of koos and diurnal migrants at GI, 81% of all captured all captured birds and 89% of all observed birds in birds from 1995-1999 and 85% of all observed birds 1997. Results at HP in other years si1Ke 1993 were from 1994-1999wereBiackpoll Warblers. TheYel- 92 McNAIRET AL.

TABLE 2. Estimated number of observations, number of days observed, and range of dates for each species ofNearctic-Neotropic landbird migrant at Harrison Point, Barbados, from autumn 1993-1996 and 1998-1999 (52 days). The number of birds captured in mist-nets during non-standardized operations in 1998-1999 (31 days) is also given.

Observations Captures Number Number Range Number Number Range Spec ies• observed of days of dates captured of days of dates Nocturnal Migrants Coccyzus am ericanus 56 27 29 Sep-13 Nov Vireo o. olivaceus 3 3 6-23 Oct 2 2 27 Sep-6 Nov Pllrula mnericana I 22 Oct Dendroica petechia 3 3 ll-l80ct Dendroica striata 13 1 40 26 Sep-8 Nov Mniotilta vuria 7 Oct Setophaga ruticilla 5 4 24 Sep-7 Nov Protonotaria citrea I I 60ct Seiurus noveboracensis 2 2 17 Oct-6 Nov Oporornis agilis 6Nov Wilsonia canadensis 31 Oct Piranga rubra I olivacea 20 Sept Jcterus galbula 25 Oct Diurnal Migrantsb Chaetura pelagica 3 2 30-31 Oct Riparia riparia 17 2 23 Oct-6 Nov Petrochelidon pyrrhonota 7 2 3 Oct-6 Nov Hirundo rustica 18 2 23 Oct-6 Nov Dolichonyx otyzivorus 65 5 2-24 Oct 'species names not mentioned in text or at bottom of Table l include: Canada Warbler (Wilsonia canadensis), Summer Tanager (Piranga rubra), and Baltimore Oriole (Icterus gafbula) bthc data for all four diurnal migrants are incomplete low-billed Cuckoo was the second most numerous Yel1ow-billed Cuckoos and Indigo Buntings, were nocturnal migrant at HP, where its frequency of 16.7 birds/1000 net hours (from 1 October, the first occurrence was similar to Blackpoll Warbler, but day we captured a Nearctic-Neotropic migrant), Yellow-billed Cuckoo was rare at GI. Red-eyed including 13 birds/1000 net hours for Blackpoll Vireo was the third most numerous nocturnal mi­ Warblers only. The capture rate in 1998-1999 com­ grant at HP in 1997 ( 10% of all captured birds ex­ bined was 3.8 birds/] 000 net hours. Migratory vol­ eluding Yellow-billed Cuckoos and Tndigo Bmlt­ ume at GI as measured by non-standardised mist­ ings) and it also occurred (six captured birds, one net efforts was higher although still low. The cap­ seen) at Gl. Other nocturnal migrants we captured ture rate from 1995-1999 combined was 85 .6 birds/ or observed at both sites included a large number 1000 net hours, including 69.6 birds/1000 net hours of scarce transients or apparent vagrants. Among for Blackpoll Warblers only. Excluding 1998 data, diurnal migrants, only Barn Swallows and Bobo­ capture rates declined to 48 birds/] 000 net hours links occurred at both sites; Bobolinks were rela­ and 33.5 birds/ 1000 net hours for all birds and tively abundant and frequent migrants at HP in Blackpol1 Warblers only, respectively. 1997 (Table I), mainly in adjacent sugarcane fields. Recaptures.- At HP, the only recaptured birds Migratory volume as measured by mist-net were two Red-eyed Vireos (often banded; 20%) in captures was low at HP. Capture rates in 1997 for all 1997, both 2 days after the original capture date. At nocturnal Nearctic-Neotropic migrants, excluding GI, the only recaptured birds were three B1ackpoll Nearctic-Neotropic Landbird Migration 93

TABLE 3. The seasonal distlibution of Yellow-billed regularly in early November. Among diurnal mi­ Cuckoos during autumn migration at Harrison grants, the number of hirundinids and Bobolinks Point, Barbados, based on the daily estimated total peaked in early to mid-October; Bobolinks were of birds per day for 5-day periods from 1993-1999. absent after late October although hirundinids Numbers in 1997 are based on both captured and continued into early November. observed birds, totals in other years on birds seen Daily timing ofoccurrence.-Excluding Black­ only (see text). poll Warblers (McNair et al. in prep.) and Indigo Buntings, more Nearctic-Neotropic migrants (n = Five-day No. of No. of No. of 18) were captured at HP during midday ( 4-8 hours after sunrise) than earlier in the morning (n = 5) or reriod da~s birds birds/da;t 2 21-25 Sep 2 0 0 later in the aftemoon (n =4; x = 9.31, p < 0.01). 26-30 Sep 6 4 0.7 Mass and fat class.-Most individuals of most l-50ct 10 13 1.3 species had low mass and little visible fat (Tables 4- 6-10 Oct 9 7 0.8 6), although variability characterised the samples. 11-15 Oct 8 12 1.5 The mean mass of unsexed Blackpoll Warblers at 16-20 Oct 15 1.2 HP in 1997 was 12.0 g, 15.8% above their mean fat­ 21-25 Oct 15 25 1.7 free mass. The mean mass of Blackpoll Warblers at 26-30 Oct 11 8 0.7 Gl was also low (11.2 g), 8.3% above their mean fat­ 31 Oct- 4 Nov 9 9 1.0 free mass. The mean mass of unsexed Red-eyed 5-9 Nov 8 10 1.2 Vireos was 18.2 gat HP, 24.7% above their fat-free 10-14 Nov 1 1.0 mass, and 15.6 g at GI, 6.9% above their fat-free TOTALS 94 107 1.1 mass. The mean fat class of the Red-eyed Vireo was double that ofBlackpoll Warbler at HP and similar at Gl. The two Red-eyed Vireos recaptured at HP Warblers, two individuals 2 days later, the other lost mass (0.15 g to 0.45 g/day). The single Black­ bird 9 days later. poll Warbler at GI that was re-measured maintained Ageclasses.-AtHPin 1997, 17 (23%)Blackpoll its mass. Warblers were AHY birds. Only three of 36 (8%) Fat-load as a percentage of mean fat-free mass other Nearctic migrants we captured at HP were of 15 selected nocturnal Nearctic-Neotropic mi­ AHY birds, including one of ten (1 0%) Red-eyed grants captured in mist-nets at both HP and GI dur­ Vireos, a Gray-cheeked Thrush and a Swainson's ing autumn migration averaged approximately 15- Thrush. Al1 remaining i11dividuals of the other nine 20%, higher than nine of the same species captured species we captured at HP were HY birds. At GI, 39 during spring migration on East Ship Island, Mis­ of 118 (33%) Blackpoll Warblers were AHY birds sissippi, following a long over-water flight across (excluding 14 birds of unknown age). Of all indi­ the Gulf of Mexico {Table 5). Along the northern viduals of the other 13 species we captured at GI, Gulf coast these birds averaged approximately 7% three of22 (14%) were AHY birds (excluding eight fat-load as a percentage offat-free mass. birds of unknown age). Flight range estimates.-Ignoring differences Seasonal timing of occurrence.- The low num­ among 'fallout' birds and other Blackpoll Warblers ber of birds and restricted sampling period at GT did at HP (McNair et al. in prep.), Blackpolls had esti­ not petmit further analyses for most species except mated flight ranges of about 435-895 km at HP and to present the range of dates of occurrence (Tables 235-475 km atGI. Red-eyed Vireos had an estimated I and 2). At HP, mid- to late-October was the peak flight range of I 015 km at HP and 285 km at Gl. Ex­ of migration for B1ackpo11 Warblers and Yel1ow­ cluding Scarlet Tanager at HP, which was below its biJied Cuckoos (Table 3); detailed analyses of mean fat-free mass, the flight range estimates for Blackpoll Warbler will be presented elsewhere the other nocturnal Nearctic-Neotropic migrants at (McNair et al. in prep.). Blackpolls were scarce after HP and GI were similar, with a mean for all species October although Yellow-billed Cuckoos occurred combinedofapprox.imately600 krn (range: HP, 350- 94 McNA!RET AL.

TABLE4. Mass and fat class for 13 species of nocturnal Nearctic-Neotropic landbird migrants captured in 3 mist-nets at Harrison Point, Barbados, from 29 September to 9 November 1997 and in 1998 , and mass and fat class for 14 species captured at Guana Island, British Virgin Islands, from 1995-1998•.

Harrison Point, Barbados Guana Island, British Virgin Islands Mass (g) Fat class Mass {g) Fat class Speciesb Mean±SD(range) Mean±SD(range) Mean±SD(range) Mean±SD(range) Coccyzus american us 51.9±7.4(44.3-61.3) 0 Vireo o. olivaceus 18 .2±1.3(16.5-20.9) 1.5±0.9(0-3) 15.6±0.8(14.1-16.5) 0.4±0.4(0-1) Catharus m. minimus 27.2 0 Catharus ustulalus 30.5 Vermivora c!uysoptera 7.6 0 Parula americana 8.15±0.6 o.sc Dendroica petechia 8.9 0 Dendroica pensylvanica 9.5 1 Dendroica magnolia 7.9 0.5 Dendroicn tigrina 9 nad Dendroica caerulescens 8.5±1 .7(7.3 -9.7) 0.25±0.35(0-0.5) Dendroica striata0 11.97±1.2(8.9-15.2) 0.7±0.8(0-3) 11.2±1.2(9-14.7) 0.5±0.5(0-2) Mniotilta varia 10.4±1.1(9-12) 0.4±0.4(0-1) Setophaga ruticilla 9.1±0.1(9-9.2) 1±1.4(0-2) 7.8 0.5 Seiurus aurocapillus 19±2.6(16-21) 0 Seiurus noveboracensis 16.9±1.4(16-19.3) 0 Oporornis formosus 12f±l.I(l1.9- 13.5) 0 14.1 0 Oporornis agilis 12.9 0 Piranga olivacea 22.8 0 Pheucticus ludovicianus 37.4 0 30.2 Passerina cyaneag 14.3±0.5(13.6-14.9) 0.4±0.5(0-1) 16.5 2 "no Ncarctic-Neotropic landbird migrants were captured at HP or GI in 1999 bsample sizes given in Table I

I 050 km; GI, 265-975 km; Table 6). nets substantially increased our ability to detect migrants at HP and Gl, especially secretive species DISCUSSION such as Catharus thrushes and Oporornis warblers that occupy dense habitats. The timing of our sam­ We have provided the first quantitative data pling periods (primarily October) in the eastern Car­ using mist-net captures of ground-based Nearctic­ ibbean coincided with the migration of Nearctic­ Neotropic landbird migrants during autumn migra­ Neotropic landbirds (Richardson 1976, 1980; tion in the eastern Caribbea11. Our results document Holland and Williams 1978; Williams and Williams that autumn Nearctic-Neotropic landbird migration 1978a; Bond 1985; Bosque and Lentino 1987, is a regular phenomenon over the eastern Carib­ Williams 1985; Raffaele 1989; Pashley and Hamilton bean for a few relatively abundant species moving 1990; Hutt et al., in prep.). Continued and more ex­ to their winter ra11ge in South America, and also tended observer effort would augment and enhance includes a large variety of scarce species as would our knowledge of ground-based Nearctic-Neotropic be predicted by the renoW11ed vagrancy of long­ land bird migration during autumn in this region. distance migrants (Grinnell1922). The use of mist- Nonetheless, we have shown that migration as Nearctic-Neotropic Landbird Migration 95

TABLE 5. Fat-load as a percentage of mean fat-free Winker (1 995b), but is consistent with their winter mass of 15 selected noctumal Nearctic-Neotropic range in South America (Paynter 1995). The conun­ landbird migrants captmed in mist-nets during dmms about earlier evaluations of its status in the autumn migration in the eastem Caribbean at eastern Caribbean are presented and discussed in Harrison Point (HP), Barbados, and Guana Island Keith (1997) and McNair et al. (1999). (Gl), British Virgin islands" compared to nine ofthe We verified or observed some other species same species captured during spring migration on for the first time in the eastern Caribbean (see East Ship Jsland (ESI), Mississippib, following a McNair et al. 1999, Sibley and Arendt in prep.). long over-water flight across the Gulf of Mexico. Local environmental conditions such as the ab­ Fat-free masses were obtained from published sence of surface water and appropriate habitat at weights (see text). HP undoubtedly accounted for the scarcity of Prothonotary Warblers (Protonotaria citrea) and Species HP GI ESI Northern Waterthmshes (Seiurus noveboracensis), Coccyzus american us 10.9 -08 two of the few Parulidae that overwinter regularly in Vireo o. olivaceus 24.7 6.9 2 8-6.9 Barbados (principally in mangrove forest at Graeme Catharus m. minimus 7.9 Hall Swamp; cf., Wunderle and Waide 1993, Wal­ Catharus ustulatus 26.1 0.5-9.6 lace et a!. 1996). 14.7-23.1 Parula americana 37.4 The most abundant species we recorded in the Dendroica pensylvanica 18.3 11.1 Dendroica magnolia 14.2 2.6-9.8 eastern Caribbean winter primarily in South Amer­ Dendroica caerulescens 11.3 ica (Bam Swallow [Hirundo rustica]) or winter Dendroica striata 15.8 8.3 exclusively or almost exclusively in South America Setophaga ruticilla 40.2 20.2 4.8-10 9 (Biackpoll Warbler, Yellow-billed Cuckoo, Red-eyed Seiurus aurocapill'us 22.4 Vireo and Bobolink; Paynter 1995,American Ornith­ Seiurus noveboracensis 23.5 ologists' Union 1998). All species that occurred at Oporornis.formosus 11.8 24.1 HP, except Northern Rough-winged Swallow (Stel­ Piranga olivacea -5 .5 -2.4-8.2 Passerina cyanea 15.9 33.7 0.3-1 1.9 gidopteryx serripennis), and all species at GI 'sample sizes given in Table 1 except Nashville Warbler (Vermivora ruficapilla), bsample sizes given in Kuerzi et al. (1991) and Yong and have been recorded at least once during winter in Moore ( 1997); mass data for Catlwrus m. minimtts South America (Paynter 1995), although records of was obtained from Cameron Parish, Louisiana several species (e.g., Golden-winged Warbler [V. chrysoptera], Kentucky Warbler and Indigo Bunt­ ing] have been restricted to northwestern South determined through sampling of grounded land­ America (Paynter 1995). Northern Rough-winged birds is more pronounced than heretofore appreci­ Swallow has been observed in the Netherlands ated although migratory volume is generally low. Antilles (Voous 1983) and Nashville Warbler has 111e higher volume at Gl can only be attributed to been observed as far south as western Panama our non-standardised mist-netting protocol, plus (Ridgely and Gwynne 1989, American Ornithol­ proximity to larger numbers of wintering Nearctic­ ogists' Union. 1998). The species composition of Neotropic migrants in the Greater Antilles. Nearctic-Neotropic migrants among HP and Gl was We discovered that Red-eyed Vireo, previous­ fairly similar, although proportionally more species ly thought to be a vagrant or scarce transient in the that ptimarily winter within the West Indies eastern Caribbean, was relatively numerous at HP . occurred at GI (also see Robertson 1962, Holland Red-eyed Vireos also occurred at GI, where previ­ and Williams 1978, Pashley 1988, Wunder1e and ous surveys in the British Virgin Islands did not Waide 1993). This pattern is consistent with its cover migration during September or October (Nor­ location at the eastern end of the Greater Antilles, ton et a!. 1989). Our results indicate the autumn where most Nearctic-Neotropic landbird migrants in migration route of Red-eyed Vireo in the West In­ the West indies overwinter (Wunderle and Waide dies occurs much farther east than depicted in 1993, Wallaceetal. 1996, Wallaceetal. 1999). All 96 McNATR ET AL.

TABLE 6. Estimates ofrate ofmass loss (g/hr) as a function of mass, mean fat load (g), time of flight (hr) given mean fat load and rate of mass Joss, and distance (km) flown based on time of flight with a mean air speed of 38.5 km/hr under conditions of no wind for 15 selected nocturnal Nearctic-Neotropic landbirds at Barbados and the British Virgin Islands during autumn migration (see text).

Harrison Point, Barbados Guana Island, British Virgin Islands Mass Fat Time of Distance Mass Fat Time of Distance loss load flight flown Joss load flight flown Species (g/hr) (g) (hr) (km) (glhr) (g) (hr) (krn) Coccyzus americanus 0.26 5.1 19.7 760 Vireo o. oli vaceus 0.14 361 26.3 1015 0.14 1.01 7.4 285 Catharus m. minimus 0.20 2 10 385 Catharus ustulatus 0.23 6.32 27.2 1050 Parula americana 0.12 2.22 18.1 695 Dendroica pensylvanica 0.13 1.65 12.6 485 Dendroica magnolia 0.12 0.98 8 310 Dendroica caerulescens - 0.16 0.86 6.9 265 Deudroica striata 0.14- 1.63 1!.3- 435- 0.14 0.86 6.1· 235- 0.07" 23.3b 895' 0.07' 12.3b 475' Setophaga ruticilla 0.13 2.61 19.5 750 0.13 1.31 9.8 375 Seiurus aurocapillus 0.20 3.48 17.8 685 Seiurus noveboracensis 0.17 3.22 19.5 750 Oporornis jormosus 0.15 1.34 9.1 350 0.15 2.74 17.8 685 Piranga o!ivacea 0.19 -1.33 0 0 Passerina cyanea 0.15 1.96 12.7 490 0.16 4.16 25.4 975 'range of rate of mass loss ~>range of time of flight 'range of distance flown

Nearctic-Neotropic migrants at both sites were of groups of birds in Richardson (1976, 1980). His species that breed in eastern North America, which conclusion assumed that migrants take a constant suggests that the wood-pewee at Barbados compass heading (mean of around 152 degrees) (McNair et al. 1999) was an Eastern Wood-Pewee from departure areas in northeastern North Amer­ (Contopus virens), not Western Wood-Pewee (C. ica, from Virginia to Nova Scotia (Stoddard et al. sordidulus), although both species winter in South 1983, Williams 1985). Williams (1991) and Williams America (Paynter 1995). and Webb (1996) further modified their hypothesis Richardson (1976, 1980), Williams et a1. (1977a) tl1at the uniform orientation of Nearctic-Neotropic and Williams and Williams (l978a) stressed that landbirds resulted in a broad front migration during Nearctic-Neotropic landbirds take two routes dur­ autumn over the western North Atlantic Ocean to ing autumn migration to reach the eastern Carib­ the West Indies rather than the use of a more bean: the long overwater 'Atlantic' route across the exclusive, narrower 'Atlantic' route, with the extent western North Atlantic Ocean from northeast-em of transoceanic crossing dependent upon how far North America (e.g., Blackpoll Warbler), or the north the migrant breeds (Wi !Iiams, pers. comm.). 'Greater Antillean' route down the Atlantic slope of Williams (pers. comrn.) stated that the orientation southeastern North America through the Florida (heading of 152 degrees) of migrants from Miami, peninsula and thence southeastward through the Florida (Williams et al. 1977a), was consistent with Greater Antilles. Later, Williams (1985) ascribed broad front migration over the western North At­ Nearctic-Neotropic migration along the 'Greater lantic Ocean from departure areas he sampled far­ Anti11ean' route to the 'Atlantic' route instead, ther north. although he did not dispute two routes for the two In southern Florida, where Blackpoll Warblers Nearctic-Neotropic Landbird Migration 97 are scarce during autumn (McNair and Post 1993), eastern Caribbean. In contrast, despite their gen­ Williams et al. (l977a) documented that nocturnal erally low numbers on the ground, we believe that movements of migrant landbirds continue south­ Blackpoll Warblers in the eastern Caribbean are eastward along a single compass heading toward flying along their main transoceanic route, not the nearest coast of Cuba, not farther east; along the margin of either route. Our evidence headwinds are avoided by flying at high altitudes. supporting the 'Atlantic' route for Blackpoll War­ However, Richardson (1976) documented directed bler is indirect (Nisbet et al. 1995) although still movements of landbirds along the 'Greater An­ consistent with Nisbet et al. (1995), who predicted tillean' route to the east/south-southeast from and that few Blackpolls are grounded in the West to Puerto Rico (from Hispaniola). These movements Indies as they are taking a long over-water flight en would require reorientation (change of headings route to South America. Murray (1989) implied that from a constant compass direction) of birds once the number of grounded Blackpolls would be much they reached land over Cuba, after flying over higher in tile West Indies since he states iliey are water, assuming birds aniving in Hispaniola or 'fairly common' there during a shorter over-water Puerto Rico did not depart from areas farther north flight. in southeastern North America. We doubt that the Other nocturnal Nearctic-Neotropic migrants constant compass mechanism postulated by (and Blackpoll Warblers; McNair et al. in prep.) that Williams is valid once migrants reach Cuba, their we captured at HP (and GI; F. Sibley, pers. obs.) first main goal along the 'Greater Antillean' route; arrived throughout the day, which is consistent they probably reorient both to the west-southwest with birds undergoing long-distance migration over (toward Yucatan) and the east-southeast (toward a large water barrier on either route. While noc­ Hispaniola). Although most birds taking this route turnal movements are much heavier than diurnal winter in the Greater Antilles (excluding species movements along the ' Greater Antillean' route flying to South America, e.g., Yellow-billed Cuc­ (where birds occur in much higher densities than koo), some species also winter in the eastern along the 'Atlantic' route), the number of birds Caribbean. moving during the daytime are nonetheless sub­ Furthermore, we cannot reconcile our results stantial (Richardson 1976). Richardson ( 1976) used with the transoceanic route or its recent broad-front the term 'island-hopping' to describe the nocturnal modification as proposed by Williams, other than and diurnal movements of Jandbirds along the for Blackpoll Warbler. The combination of a large 'Greater Antillean' route. He did not specify variety yet low numbers of nocturnal migrants, the whether birds landed on 011e isla11d before depart­ proportionally low numbers of all species (ex­ ing for the next one or whether birds continued to cluding Yellow-billed Cuckoo at Barbados) com­ fly over islands sequentially. The timing of de­ pared to Blackpoll Warbler (including other species parture of nocturnal passerines during autumn mi­ that are numerous in northern or northeastern gration in the West Indies is more protracted than North America duri11g the breeding season or in more northerly latitudes (Richardson 1976, autumn migration), and the predominance of Williams et al. 1978), and may continue as long as immatures of other Nearctic-Neotropic migrants 6 hr after sunset. compared to a higher proportion of adults for Despite later departure times for many birds, Blackpoll Warbler (Nisbet et al. 1963 , Ralph 1981 ), they evidently are not 'islm1d-hopping' (Richard­ suggest that these Nearctic-Neotropic species son 1976, Keith 1997) short distances on the 'Great­ otl1er than Blackpoll Warbler probably migrated er Antillean' route. ' Island-hopping' to Barbados, along the fringe of the 'Greater Antillean' route to lying east of the Lesser Antillean arc, would also be reach the eastern Ca1ibbean, including the southern maladaptive. Outside Cuba (and possibly Hispan­ Lesser Antilles (Richardson 1976). If other Nearctic­ iola), our Nearctic-Neotropic migrants had enough Neotropic 1andbirds are migrating over the western time and fat to arrive at their destination before North Atlantic Ocean, very few individuals of any dawn or within 2-3 hr after dawn if they are only of these species must use this route to reach the 'island-hopping' short distances (Gauthreaux 1978, 98 McNAIR ET AL.

Bingman 1980, Wiedner et al. 1992). Most of our the scarcer species we captured or observed in the Nearctic-Neotropic migrants, although of! ow mass, eastern Caribbean winter primarily in Middle Amer­ were not emaciated, unlike many trans-Gulf land­ ica and may have been wind-drifted vagrants birds during spring migration (Kuenzi et al. 1991 ). displaced eastward. However, wind-drifted vagran­ Although our sample sizes of other Nearctic-Neo­ cy to the eastern Caribbean from regions along the tropic migrants were low, the modest amount of fat Gulf of Mexico west of the Florida peninsula is un­ above fat-free mass of many captured birds at land­ likely, since none of the preferred flight directions fall on two small islands in the eastern Caribbean of trans-Gulf migrants are to the southeast during may be 'insurance' when flying over a large eco­ autumn when northerly winds are infrequent and logical barrier (long over-water distances). Most usually from the nmtheast (Able 1972). birds had sufficient fat for continued flight, es­ The relative abundance and frequency of oc­ pecially at Barbados where many migrants could currence of Yellow-billed Cuckoo, Red-eyed Vireo have covered the distance of approximately 450 km and Bobolink at Barbados suggest these three to South America. The high mass of Red-eyed species may be candidates for the long overwater Vireos compared to other species at Barbados is route across the western North Atlantic Ocean to difficult to explain; these birds could have reached South America. However, no compelling evidence South America easily, even allowing for a reservoir exists which supports this possibility. Unlike Black­ of unused fat as 'insurance'. Birds at Gl would oll Warblers, surveys of these species' distribu­ require longer times to refuel for the longer cros­ tions during autumn indicate that they initiate mi ­ sing to South America (approximately 880 km), if gration from southeastern Nmth America, Yellow­ this is their destination. Alternatively, non-emaciat­ billed Cuckoos and Red-eyed Vireos as both trans­ ed birds may have landed at both islands during Gulf migrants and down the Florida peninsula and daytime because conditions are more favorable for Bobolinks from the Atlantic slope only (Chapman migration at night (Biebach 1992). Regardless, most 1890; Bent 1940, 1958; Hamilton 1962, Taylor and of our other Nearctic-Neotropic migrants have pro­ Anderson 1973, Crawford 1980, 1981, Taylor and bably flown appreciable distances between depar­ Kershner 1986, Robertson and Woolfenden 1992, ture areas along the 'Greater Antillean ' route and Stevenson and Anderson 1994, Winker 1995b, arrival at GI and Barbados, regular migrants and Remsen et al. 1996, Woodrey and Moore 1997). vagrants alike. Aboard ships in the western Nmth Atlantic Ocean, Rather than take the 'Greater Antillean' route, only one Bobolink was captured and no others Rappole et al. ( 1979) suggested that some migrants were reported seen (McClintock et al. 1978), where depatting from southern Florida during autumn may the status of Nearctic-Neotropic landbird migrants fly southwest to Yucatan and Central America. other than Blackpoll Warbler is consistent with Although Williams et al. (1977a) failed to detect wind-drifted vagrancy {Munay 1989). Williams et strong southwest flights, recent studies using a!. (I 977b) suggested that Yellow-hilled Cuckoos WSR-88D radar have confirmed that landbird mi­ crossed the western North Atlantic Ocean and saw grants may depart southwest from southem Florida cuckoos greater than 320 km from the coast, but during autumn, although the flights are fewer and otherwise cited no specific reports. Furthermore, its of lesser magnitude than north of Tampa (K. P. status as an uncommon autumn migrant in the Able, pers. comm.). Nearctic-Neotropic migrants northern Bahamas (parallel to the southern Florida that predominantly winter in this region are widely coast where it is numerous) compared to its greater dispersed during autumn migration in the Florida abundance in the southern Bahamas (and Greater peninsula (Robertson and Woolfenden 1992), al­ Antilles) farther south (Raffaele et al. 1998) is also though several of these species are generally inconsistent with passage ofYellow-billed Cuckoos scarce on the southeastern Atlantic coastal plain in over the western North Atlantic ocean. Red-eyed autumn (e.g., Golden-winged Warbler, which has Vireos have not been captured or seen at all. The nonetheless increased recently in the West Indies status of these three species during autumn migra­ [Gochfeld 1974, Raffaele 1989, this study]). Some of tion in the eastern Caribbean is consistent with ·· ~ ------··--- ·· ------

Nearctic-Neotropic Landbird Migration 99 their status elsewhere in the West Indies. Ye1low-billed Cuckoos pass through the largest Hilditch eta!. ( 1973) and Williams and Williams islands of the Greater Antilles during October, but (1978a) stressed that few of the many birds which cited no numbers. 'Fallouts' of Yellow-billed fly over the West Indies are grounded, in part be­ Cuckoos may have been overlooked in the northern cause birds can frequently detour around ap­ and eastern Caribbean, but their primary restriction proaching storms. This assessment agrees with our despite their visibility (large size) to the southem observations of the frequent absence of 'fallouts' portion of the Caribbean Sea is consistent with an during autumn migration even when storms occur. over-water crossing of the Caribberu1 Sea (fat birds In addition, the occurrence of birds in waves sepa­ have been collected dming September and October rated by several days with bttle or no migration in the Dominican Republic and Puerto Rico; (Williams et al. 1977b, 1978; Williams 1985) would Schwartz and Klinikowski 1965), not over the west­ also contribute toward the absence of 'fallouts' em North Atlantic Ocean. Their rarity at GI despite during storms. Nonetheless, documented 'fallouts' suitable habitat (also generally rare during autumn of nocturnal Nearctic-Neotropic landbirds during at St. Croix, American Virgin Islands, where F. W. autumn migration have occurred in the West Sladen [pers. comm.] had 34 birds on 19 days over Indies, including the eastern Caribbean. Most 'fall­ 10 yr [1980-1989]) is also inconsistent with migra­ outs' have been primarily limited to two species. tion over the western North Atlantic Ocean. Docu­ 'Fallouts' of Blackpoll Warblers are documented mented 'fallouts' of Yellow-billed Cuckoos have elsewhere (McNair et a!., in prep.), but have oc­ also occun·ed independently of 'fallouts' of Black­ curred throughout the northern, eastem, and poll Warblers, e.g., Kale et a!. (1969), Meier et al. southern Caribbean during autumn, e.g., in the (1989), this study. Except for several thrushes and Bahamas (Kale eta!. 1969). Yellow-billed Cuckoos some parulids (Kale et al. 1969, Robertson 1970), no are rare to locally common breeders in the Greater other species have been documented to have Antilles (Kepler and Kepler 1978, Raffaele et a!. occurred in substantial numbers during 'fallouts' of 1998) and at two sites in the Lesser Antilles, St. either Yellow-billed Cuckoos or Blackpoll Warblers Kitts and St. Martin (Steadman et a!. 1997, Feld­ in the West Indies, although this is certainly pos­ mann et a!. 1999), but their breeding status should sible for species [e.g., Red-eyed Vireo, Connecticut not unduly affect assessment of their status during Warbler ( 0. agilis)] that arrive at north em South autumn migration, which occurs primarily from late America after an over-water crossing of the Carib­ September to November (not ' very few' birds in bean Sea during autumn mi gration. We believe the November and not 'uncommon to rare ' in the scarcity of conspicuous 'fallouts' of species other Lesser Antilles contra Raffaele eta!. 1998). than Blackpoll Warbler in the northern Caribbean Most 'fallouts ' (arbitrarily defined as ;::: 10 strengthens our argument that we have not over­ birds/day) of the Yellow-billed Cuckoo have oc­ looked other possible candidate species for an curred in the southern Caribbean, at the Nether­ over-water crossing of the western North Atlantic lands Antilles, Barbados and Tobago, near north­ Ocean. em South America (Voous 1983, ffrench 1993, Hutt In addition, low numbers, predominance of eta!. in prep.). Bonhote (1903) collected 12 Yellow­ immatures of birds captured or salvaged aboard billed Cuckoos on 15 October 1901 atBirdRock off ships, generally low masses and low fat classes, Crooked Island in the Bahamas and Robertson and improbable destinations based on the winter (1970) stated Yellow-billed Cuckoos in association range and known migratory routes of most with other Greater Antillean migrants were numer­ Nearctic-Neotropic migrants other than Blackpoll ous on 14 October 1969 at a lighthouse at Cayo Warblers seen south of Bermuda (only two species Caiman off Caibarien near the coast of Cuba, but listed by McClintock et al. [ 1978] winter in South both locations in the Straits of Florida would be America) do not support the long over-water route consistent with migration down tl1e Florida pen­ across the western North Atlantic Ocean during insula. Raffaele (1989) and Raffaele et al. (1998) autumn (Ralph 1981 , Murray 1989; contra Mc­ stated that sometimes very large concentrations of Clintock eta!. 1978, Wi !Iiams and Williams 1978b, 100 MCNAIR ET AL.

Willlams 1985 [although Williams' two pub­ Sibley for assisting with banding on Guana Island. lications included a retraction for species that do We thank F. W. Sladen for sharing unpublished not winter in the Neotropics]). The occurrence of data from St. Croix. Finally, we thank K. P. Able, W. these species over the western North Atlantic 1. Arendt, W. Post, T. C. Williams, and K. Winker Ocea11 is consistent with wind drift from the North for their reviews of our manuscript. American mainland. Recently, Morris et al. (1996) nominated Ten­ LITERATURE CITED nessee Warbler (V. peregrina) as another potential trans-oceanic migrant over the western North At­ ABLE, K. P. 1972. Fall migration in coastal Louisiana lantic. However, this species is a trans-Alleghanian and the evolution of migration patterns in the migrant in continental North America (e.g., one of Gulfregion. Wilson Bull. 84:231-242. the two most abundant parulids during autumn AMERICAN 0RL'IITHOLOGISTS' UNION. 1998. Check­ migration at high elevations of the Southern list of North American birds. 7th ed. American Appalachian Mountains; McNair, unpubl.) that Ornithologists' Union, Washington, D.C. 829 moves to the northern Gulf coast and onward to the pp. winter range from southern Mexico to northwest BENT, A. C. 1940. Life histories of North American South America (Paynter 1995). Furthermore, the cuckoos, goatsuckers, hummingbirds, and Tennessee Warbler is found 011ly in the notihem their allies. Bull. U.S. Nat!. Mus. 176:1-506. and western Caribbean on the eastern fringe of its BENT, A. C. 1958. Life histories of North American autumn migration route and is generally rare to blackbirds, orioles, tanagers, and allies. Bull. U. uncommon here (Gochfeld I 974, Raffaele et al. S. Natl. Mus. 211:1-549. 1998). Uncritical evalttation ofthe autumn migration BIEBACH, H. W. 1992. Flight-range estimates for route of Tennessee Warbler l1as not contributed to small trans-Sahara migrants. Ibis 134:S47-S54. the legitimate debate about transoceanic migration BINGMAN, V. 1980. Inland morning flight behavior of ofB!ackpoll Warblers and other Nearctic-Neotropic nocturnal passerine migrants in eastern New landbirds from northeastern North America to the York, USA. Auk 97:465-472. West Indies and South America (see Nisbet eta!. BOND, J. 1985. Birds of the West Indies. 5th ed. 1995). Excluding Blackpoll Warbler, an unknown Collins, London. 256 pp. propmiion of a few species (e.g., Cape May BONHOTE, J. L. 1903. Bird migration at some ofthe Warbler [D. tigrina], Com1ecticut Warbler and Bahama lighthouses. Auk20:169-179. NoJihern Waterthrush) may migrate during autumn BOSQUE, C., AND M. LENTINO. 1987. The passage of over the western North Atlantic Ocean after depart­ North American migratory land birds through ing from north of southeastern North America, but xerophytic habitats on the westem coast of this has not yet been convincingly documented. Venezuela. Biotropica 19:267-273. CHAPMAN, F. M. 1890. On the winter distribution of ACKNOWLEDGEMENTS the Bobolink (Dolichonyx oryzivorus) with re­ marks on its routes of migration. Auk 7:39-45. We thank R. Carter, Director, Youth Affairs, CHILD, G. I. 1969. A study of nonfat weights in and H. Haynes, Chief, Barbados Youth Service, for migrating Swainson's Thrushes (Hylocichla allowing and facilitating accommodation and board ustulata). Auk 86:327-338. for DI3M at Harrison Point, St. Lucy, and R. CONNELL, C. E., E. P. ODUM,ANDH. KALE.l960. Fat­ Marshall, Environmental Officer, EnvironmentDiv­ free weights of birds. Auk 77:1-9. ision, Ministry of Health and the Environment, for CRAWFORD, R. L. 1980. Wind direction and the issuing a scientific collecting pennit for our re­ species composition of autumn TV tower kills search. We also thank the Jarecki family for allow­ in northwest Flmida. Auk 97:892-895. ing us to work on Guana Island, the Falconwood CRAWFORD, R. L. 1981. Bird casualties at a Leon Foundation and J. Lazell for making work on GI County, Florida, TV tower: a 25-year migration possible, and A. Olivieri, J. Richardson, and M. study. Bull. Tall Timbers Res. Sta. 22:1-30. ------··--

Nearctic-Neotropic Landbird Migration 101

DUNNING, J. B. 1993. CRC handbook of avian body KALE, H. W., 11, M. H. HUNDLEY, AND]. A. TuCKER. masses. CRC Press, Boca Raton, FL. 371 pp. 1969. Tower-killed specimens and observa­ FELDMANN, P ., E. BENITO-ESPINAL, ANDA . R. KEITH. tions of migrant birds from Grand Bahama Is­ 1999. New bird records from Guadeloupe and land. Wilson Bull. 81 :258-263. Martinique, West Tndies. J. Field Omithol. 70: KEITH, A. R. 1997. The birds of St. Lucia, West In­ 80-94. dies. British Ornithologists' Union Check-hst FFRENCH, R. 1993. Further records of birds on 15:1-176. Trinidad and Tobago. Living World (J. Trin. KEPLER, C. B., ANDA. K. KEPLER. 1978. Status and Tob. Field Nat. Club) 1993-1994:28-31. nesting of the Yellow-billed Cuckoo in Puerto FoSTER, M. S., AND P. F. CANNELL. 1990. Bird Rico. Auk95:417-419. specimens and documentation: critical data for KUENZI, A. J., F. R. MOORE, ANDT. R. SIMONS. l991. a critical resource. Condor 92:277-283. Stopover of Neotropical land bird migrants on GAUTHREAUX, S. A., JR. 1978. Importance of the East Ship Island following trans-Gulf migra­ daytime flights ofnoctumal migrants: redeter­ tion. Condor 93:869-883. mined migration following displacement. Pp. LARKrN, R. P., D. R. GRIFFIN, J. R. TORRE-BUENO, 219-227 in Animal migration, navigation and AND J. TEAL. 1979. Radar observations ofbird homing (K. Schmidt-Koenig and W. T. Keetm1, migration over the western North Atlantic eds.). Springer-Verlag, Berlin. Ocean. Behav. Ecol. Sociobiol. 4:225-264. GOCHFELD, M. 1974. Status of the genus Vermivora LAZELL, J. 1996. Guana Island: a natural history (Aves Parulidae) in the Greater Antilles with guide. Conserv. Agency Occas. Pap. 1:1-20. new records from Jamaica and Puerto Rico. MCCLINTOCK, C. P., T. C. WILLIAMS, AND J. M. Carib. J. Sci. 14:177-181 . TEAL. 1978. Autumnal migration observed GRINNELL, J. 1922. The role of the "accidental." from ships in the western North Atlantic Auk 39:373-380. Ocean. Bird-Banding 49:262-275. HAMILTON, W. J., III. 1962. Bobolink migratory McNAIR, D. B., E. B. MASSIAH, AJ\D M. D. FROST. pathways and their experimental analysis un­ 1999. New and rare species of Nearctic land­ der night skies. Auk 79:208-233. bird migrants during autumn for Barbados and HILDITCH, C. D. M., T. C. WILLIAMS, AND T. C. T. the Lesser Antilles. Catib. J. Sci. 35:46-53. NISBET. 1973. Autum11al bird migration over McNAIR, D. B., AND W. POST. 1993. Autumn mi­ Antigua, WJ. Bird-Banding 44:171-179. gration route of Blackpoll Warblers: evidence HOLLAND, C. S, AND J. M. WILLIAMS. 1978. Obser­ from southeastern Nmth America. J. Field vations on the birds of Antigua. Amer. Birds Omithol. 64:417-425. 32:1095-1105. MEIER, A. 1., R. E. NOBLE, AND H. A. RAFFAELE . HUNT, P. D., AND B. C. ELIASON . 1999. Blackpoll 1989. The birds of Desecheo Island, Puerto Warbler (Dendroica striata). In The birds of Rico, including a new record for Puerto Rican North America, no. 431 (A. Poole and F. Gill, territory. Carib. J. Sci. 25:24-29. eds.). The Birds of North America, Jnc., Phila­ MORRIS, S. R., D. W. HOLMES, ANDM. E. RICHMOND. delphia. 1996. A ten-year study of the stopover pat­ RUSSELL, D.]. T., AND A. P. LAMBERT. 1980. New terns of migratory passetines during fall estimates of weight loss of birds dming uoc­ migration on Appledore Island, Maine. Condor tumal migration. Auk 97:547-558. 98:395-409. HUTI, M . B., H. F. HUTT, P. A. BUCKLEY, E. B. MURRAY, B. G., JR. 1989. A critical review of the MASSIAH, M.D. FROST, AND F. G. BUCKLEY. In transoceanic migration of the Blackpoll War­ prep. The birds of Barbados. British Ornithol­ bler. Auk 106:8-17. ogists' Union Check-list. N ISBET, I. C. T. 1970. Autumn migration of the JAMES, F. C., AND H. H. SHUGART, JR. 1970. A quan­ Blackpoll Warbler: evidence for long flight pro­ titative method of habitat description. Aud­ vided by regional survey. Bird-Banding 41 :207- ubon Field Notes 24:727-736. 240. ------

102 McNATRETAL

NISBET, I. C. T., W. H. DRURY, JR., AND J. BAIRD. ing of migration and route selection in North 1963. Weight loss during migration. Part I: de­ American songbirds. Pp. 199-214 in Proceed­ position and consumption of fat by the Black­ ings of the First Welder Wildlife Foundation poll Warbler Dendroica striata. Bird-Banding Symposium(D. L Drawe,ed.). Welder Wildlife 34:107-138. Foundation, Sinton, TX. 276 pp. NISBET, l. C. T., D. B. McNAIR, W. POST, ANDT. C. REYISEN, J. V., JR., S. W. CARDIFF, AND D. L. DITT­ WILLIAMS. 1995. Transoceanic migration of the MANN. 1996. Timing of migration and status of Blackpoll Warbler: summary of scientific evi­ vireos (Vireonidae) in Louisiana. J. Field Omi­ dence and response to criticisms by Murray. J. thol. 67:119-140. Field Omithol. 66:612-622. RICHARDSON, W. J. 1976. Autumn migration over NORTON, R. L 1981. Additional records and notes Puerto Rico and the western Atlantic: a radar ofbirds in the Virgin Islands. Amer. Birds 35: study. Ibis 118:309-332. 144-147. RICHARDSON, W. J. 1980. Autumn landbird migra­ NORTON, R. L, R. M. CHIPLEY, ANDJ. D. LAZELL, JR. tion over the western Atlantic Ocean as evi­ 1989. A contribution to the ornithology of the dent from radar. Proceedings of the 17th Inter­ B1itish Virgin Islands. Carib. J. Sci. 25:115-118. national Ornithological Congress at Berlin, PASHLEY, D. N. 1988. Warblers of the West Indies. 1978:501-506. J. The Virgin Islands. Carib. J. Sci. 24:11-22. RIDGELY, R. S.,ANDJ. A. GWYNNE, JR. 1989.Aguide PASHLEY, D. N., AND R. B. HAMILTON. 1990. War­ to the birds of Panama. 2nd. ed. Princeton Uni­ blers of the West Indies. TIL The Lesser Antil­ versity Press, Princeton, NJ. 534 pp. les. Carib. J. Sci. 26:75-97. ROBERTSON, W. B., JR. 1962. Observations on the PAYNTER, R. A., JR. 1995. Nearctic passerine birds of St. John, Virgin Islands. Auk 79:44-76. migrants in South America. Pub!. Nuttall ROBERTSON, W. B., JR. 1970. Florida region. Audu­ Omithol. Club 25:1-126. bon Field Notes 24:33-38. PENNYCUICK, C. J. 1989. Bird flight performance: a ROBERTSON, W. B., JR., AND G. E. WOOLFENDEN. practical calculation manual. Oxford University 1992. Florida bird species: an annotated list. Press, Oxford. 153 pp. Florida Ornithol. Soc. Spec. Pub!. 6:1-260. PYLE, P ., S. N. G. HOWELL, R . P. YUNICK, AND D. F. ROGERS, D. T., JR., AND E. P. 0DUM. 1964. Effect of DESANTE. 1987. Identification guide to North age, sex, and level of fat deposition on major American passerines. Slate Creek Press, Bo­ body components in some wood warblers. linas, CA. 278 pp. Auk 81:505-513. PYLE, P., S. N. G. HOWELL, D. F. DESANTE, R. P. ROGERS, D. T., JR., AND E. P. 0DUM. 1966. A study YUNTCK, AND M. GUSTAFSON. 1997. Identifi­ of autumn postmigrant weights and vernal fat­ cation guide to North American birds. Part J. tening of North American migrants in the tro­ Columbidae to Ploceidae. Slate Creek Press, pics. Wilson Bull. 78:415-433. Bolinas, CA. 732 pp. SCHWARTZ, A., AND R. F. KLINIKOWSKJ. 1965. Ad­ RAFFAELE, H. A. 1989. A guide to the birds of Puer­ ditional observations on West Indian birds. to Rico and the Virgin Islands. Princeton Uni­ Notulae Naturae (Acad. Nat. Sci., Philadelphia) versity Press, Princeton, NJ. 254 pp. 376:1-16. RAFFAELE, H. A., J. WILEY, 0. GARRIDO, A. KEITH, STEADMAN, D. W., R. L NORTON, M. R. BROWNING, AND J. RAFFAELE. 1998. A guide to the birds of AND W. J. ARENDT. 1997. The birds of St. Kitts, the West Indies. Princeton University Press, Lesser Antilles. Carib. J. Sci. 33:1-20. Princeton, NJ. 511 pp. STEVENSON, H. M., AND B. H. ANDERSON. 1994. The RALPH, C. J. 1981. Age ratios and their possible use birdlife of Florida. University of Florida Press, in determining autumn routes of passerine Gainesville, FL. 892 pp. migrants. Wilson Bull. 93:164-188. STODDARD, P. K. , J. E. MARSDEN, AND T. C. RAPPOLE, J. H ., M.A. RAMos,R. J. 0ELENSCHLAGER, WILLIAMS. 1983. Computer simulation of au­ D. W. WARNER,ANDC.P.BARKAN.l979.Tim- tumnal transatlantic bird migration. Anim. Nearctic-Neotropic Landbird Migration 103

Behav. 31 :173-180. Amer. 239 :166-176. TAYLOR, W. K., ANDB. H.ANDERSON.1973 . Noctur­ WILLIAMS, T. C., A.'ID J. M. WILLIAMS. 1978b. Ori­ nal migrants killed at a central Florida TV tow­ entation of transatlantic migrants. Pp. 239-251 er: autumns 1969-1971. Wilson Bull. 85:42-51. in Animal migration, navigation and homing TAYLOR, W. K., AND M.A. KERSHNER. 1986. Mig­ (K. Schmidt-Koenig and W. T. Keeton, eds.). rant birds ki11ed at the vehicle assembly build­ Springer-Verlag, Berlin. 462 pp. ing (V AB), John F. Kennedy Space Center. J. WILLIAMS, T. C., P. BERKELEY, AND V. HARRIS. Field Omithol. 57: 142-154. !977a. Autumnal bird migration over Miami TERBORGH, J. W., AND J. FAABORG. 1980. Factors studied by radar: a possible test of the wind affecting the distribution and abundance of drift hypothesis. Bird-Banding 48:1-10. North American migrants in the eastern Carib­ WILLIAMS, T. C., J. M. WILLIAMS, AND L. C. bean region. Pp. 145-155 in Migrant birds in IRELAND. 1974. Bird migration over the North the Neotropics: ecology, behavior, distribu­ Atlantic. Pp. 359-382 in Proceedings of a con­ tion, and conservation (A. Keast and E. S. ference on biological aspects of the bird/air­ Morton, eds.). Smithsonian Institution Press, craft collision problem (S. Gauthreaux, ed.). U. Washington, D.C. 576 pp. S. Air Force Office of Scientific Research, Voous, K. H. 1983. Birds of the Netherlands Antil­ Arlington, VA. les. de Walburg Press, Utrecht. 327 pp. WILLIAMS, T. C., J. M. WILLIAMS, L. C. IRELAND, WALLACE, G. E., H. G. ALONso, M. K. McNrcHOLL, AND J. M. TEAL 1977b. Autumnal bird migra­ D. R. BATISTA, R. 0. PRIETO, A. L. SOSA, B. S. tion over the western North Atlantic Ocean. ORlA, AND E. A. H. WALLACE. 1996. Winter Amer. Birds 31 :251-267. surveys afforest-dwelling Neotropical migrant WILLIAMS , T. C., J. M. WILLIAMS, L. C. IRELAND, and resident birds in three regions of Cuba. ANDJ. M. TEAL. 1978. Estimated flight time for Condor 98:745-768. transatlantic autumnal migrants. Amer. Birds WALLACE, G. E., E. A. H. WALLACE, D. R. FROEH­ 32:275-280. LICH, B. WALKER, A. KIRKCONNELL, E. S. WINKER, K. 1995a. Autumn stopover on the Isth­ TORRES, H. A CARLISLE, AND E. MACHELL. mus of Tehuantepec by woodland Nearctic­ 1999. Hermit Thmsh and Black-throated Gray Neotropic migrants. Auk 112:690-700. Warbler, new for Cuba, and other significant WINKER, K. 1995b. Neotropical stopover sites and bird records from Cayo Coco and vicinity, Middle American migrations: the view from Ciego de Avila Province, Cuba, 1995-1997. southern Mexico. Pp.l50-163 in Conservation Florida Field Nat. 27:37-51. ofNeotropical migratory birds in Mexico (M. WIEDNER, D. S., P. KERLINGER, D. A. SIBLEY, P. H. Wilson and S. A. Sader, eds.). Maine Agri­ HOLT,J. HOUGHANDR.CROSSLEY. 1992. Visible cultural and Forest Experiment Station Misc. morning flight ofNeotropicallandbird migrants Publ. 727. at Cape May, New Jersey. Auk 109:500-510. WOODREY, M. S., AND F. R. MOORE. 1997. Age­ WILLIAMS, T. C. 1985. Autumnal bird migration over related differences in the stopover of fall land­ the Windward Caribbean Islands. Auk 102:163- bird migrants on the coast of Alabama. Auk 167. 114:695-707. WILLIAMS, T. C. 1991. Co11stant compass orienta­ WUNDERLE, J. M., JR., AND R. B. WAIDE. 1993. tion for North American autumnal migrants. J. DistJibution of overwintering Nearctic mig­ Field Ornithol. 62:218-225. rants in the Bahamas and Greater Antilles. WILLIAMS, T. C., AND T. WEBB, Ill. 1996. Neotropi­ Condor 95:904-933. cal bird migration during the ice ages: Olienta­ YoNG, W., ANDF. R. MooRE. 1997. Spring stopover tion and ecology. Auk 113: I 05-118. of intercontinental migratory thrnshes along WILLIAMS, T. C., AND J. M. WILLIAMS. 1978a. An the northern coast of the Gulf of Mexico. Auk oceanic mass migration of land birds. Sci. 114:263-278. ------

Pp. 104-110 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. II, 2002.

OBSERVATIONS OF PELAGIC SEABIRDS WINTERING AT SEA IN THE SOUTHEASTERN CARIBBEAN

WILLIAM L. MURPHY 8265 Glengarry Court, Indianapolis, IN 46236, USA

ABSTRACT.-1 report observations, including several significa11t distributional records, of 16 species of seabirds wintering at sea in the southeastern Caribbean during cruises from Bonaire to the Orinoco River {5-13 January 1996, 3-12 March 1997 and 23 December 1997- I January 1998). A few scattered shearwaters (Calonectris diomedea and Puffinus lherminieri) were seen. Storm-Petrels (Oceanites oceanicus and Oceano­ drama leucorhoa), particularly the latter species, were often seen toward the east. Most tropicbirds (Phaethon aethereus) and gulls (Larus atricilla) were near Tobago. Boobies were common; Sula leucogaster outnumbered S. sula by about 4: I and S. dactylatra was scarce. Frigatebirds (Fregata magnificens) were strictly coastal. Several skuas (Stercorarius slata) were seen off Venezuela. Jaegers were common, with a ratio of 90 Stercorarius pomarinus to 8 S. parasiticus to 2 S. longicaudus. Only two tern species were seen: Sterna maxima was widespread and 4,000 S. antillarum were noted south­ east of Trinidad.

RESUMEN .-Reporto observaciones, incluyendo algunos registros significativos, de 16 especies de aves marinas invernando en el sudeste del mar Caribe durante viajes realizados desde Bonaire hasta el rio Orinoco (5-13 de enero de 1996, 3-12 de marzo de 1997 y e1 23 de diciembre hasta 1 de euero de 1998). Se observaron algunos pufinos (Calonectris diomedea y Puffinus lherminieri). Las golondrinas de tormenta (Oceanites oceanicus y Oceanodroma leucorfzoa), particularmente esta ultima especie, fueron observadas con mayor frecuencia hacia el este. La mayoria de aves tropicales (Phae­ thon aethereus) y gaviotas (Larus atricilla) fueron observadas cerca de Tobago. Los piqueros fueron comunes; Sula leucogaster sobrepas6 a S. sula en una proporci6n aproximada de 4:1 y S. dactylatra fue escaso. Las fregatas (Fregata magnificens) estuvieron restringidas a las areas costeras. Se observaron algunos salteadores (Sterco­ rarius skua) cerca de Venezuela. Otros salteadores fueron comunes, con una proporci6n de 90 Stercorarius pomarinus a 8 S. parasiticus a 2 S. longicaudus. Se observaron solamente dos especies de gaviotines: Sterna maxima se encontr6 en todas partes y 4,000 S. antillm·um se registraron en el sudeste de Trinidad.

KEY WoRDS.-Charadriiformes, Netherlands Antilles, pelagic distribution, Pelecani­ fotmes, Procellariiformes, seabirds, Ca1ibbean Sea, Trinidad and Tobago, Venezuela

The status of pelagic seabirds wintering in the the region. Our current knowledge of pelagic sea­ southeastern Caribbean is poorly known since bird­ bird distribution in the regiou is summarised by ers and ornithologists seldom venture out to sea in Bond {1985) and Raffaele (1983, 1998) for the West

104 Seabird Distribution in the Southern Caribbean 105

TABLE 1. Itineraries ofthree cruises aboard the Yorktown Clipper, 1996-1998.

Date" Localities visited 01/05/96 moored at Willemstad, Curaoyao; departed for Bonaire at 1200 01 /06/96 arrived at Kralendijk, Bonaire, N.A.; departed for Mochima National Park, Venezuela, at 1300 01 /07/96 arrived at Mochima Natlonal Park at 1400; departed for Tobago at 1900 01 /08/96 cruised from Mochima National Park to Tobago 01 /09/96 arrived at Scarborough, Tobago, at 0700; departed for the Orinoco River at 1800 01/10/96 cmised to the Orinoco River; arrived at Curiapo, Venezuela, at 1400; departed for Ciudad Guayana, Venezuela, at 1900 01111 /96 arrived at Ciudad Guayana, Venezuela; departed for El Toro tributary, Venezuela, at 2100 01112/96 arrived at E1 Toro tributary, Venezuela, at 0600; departed for Trinidad at 1100 01/13/96 arrived at Port of Spain, Trinidad, at 1200 03/03/97 moored at Port of Spain, Trinidad; departed for the Orinoco River at 2000 03/04/97 cruised through the Columbus Channel to the Orinoco River 03/05/97 arrived at Rio Arature anchorage at 1330 03/06/97 explored the Orinoco River; departed for Tobago at 1030 03/07/97 cruised to Tobago; arrived at Charlotteville, Tobago, at 1000; departed for Isla Margarita at 1200 03/08/97 cmised from Tobago to Isla Margarita; arrived at Pampatar, isla Margarita, at 1900 03/09/97 moored at Pampatar, lsla Margarita; departed for Bonaire at 1000 03/10/97 cmised from Isla Margarita to Bonaire 03/11 /97 arrived at Kralendijk, Bonaire, at 0600; depa1ied for Cura9ao at 1200 03/ 12/97 arrived at Willemstad, Cura9ao, at 0600 12/23/97 moored at Willemstad, Cura.yao; depmied for Bonaire at 2300 12/24/97 arrive at Kralendijk, Bonaire, at 0600; departed for Isla Margarita at 1800 12/25/97 cruised from Bonaire to Isla Margarita 12/26/97 arrived at Pampa tar, Isla Margarita, at 0530; departed for Tobago at 1000 12/27/97 cruised from isla Margarita to Tobago; arrive at Charlotteville, Tobago, at 8:00pm 12/28/97 mooed at Charlotteville, Tobago; departed for the Orinoco River at 1300 12/29/97 arrived at Rio Arature anchorage, Venezuela, at 1400; departed for El Toro, Venezuela, at1900 12/3 0/97 moored at El Toro tributary and later at Cafio Paloma, Venezuela; departed for Trinidad at 2300 12/31 /97 cruised from the Orinoco River to Trinidad 01/01 /98 arrived at Port of Spain, Trinidad, at 0900 "month/day/year

Indies, ffrench (199 1) for Trinidad and Tobago, 1997 - 2 January 1998), I escorted a group ofbirders Meyer de Schauensee and Phelps (1978) for Vene­ aboard the educational cruise ship Yorktown Clip­ zuela, and Voous (1983) for Aruba, Bonaire and per between Curacao and the Orinoco River, Curayao (the soutl1em Netherlands Antilles). Here­ traversing approximate! y 2,000 km per trip (Table 1). in I report observations of pelagic seabirds winter­ Because the focus was on visiting islands as well ing at sea in the southeastern Caribbean, based on as on cmising, many of the longer passages were observations made during three recent cruises. traversed at night. While at sea during the day, fellow birders and 1 maintained a sea watch, record­ METHODS ing sightings of bird spec1es and their numbers. The observers were all experienced birders On three occasions between 1996 and 1998 (5- with binoculars, some of which were image-stabil­ 13 January 1996; 3-12 March 1997; 22 December ised. 1l1e number of observers at any given time 106 MURPHY ranged from one to 15, averaging about five. Obser­ range. vations were made from various points on three Audubon's Shearwater (Puffinus lherminieri) . decks ranging from 3-15 m above sea level. An -We observed one at 11 °08'N, 66°11 'W, between intercom system was occasionally used to alert Bonaire and Mochima National Park near Puerto la birders to seabirds of special interest. Because we Cruz, Venezuela, on 6 January 1996. Two were could move rapidly along or across the ship's noted at 11 °20'N, 64°47'W, southwest oflsla Mar­ decks, certain seabirds could be observed for pro­ garita, Venezuela, on 7 January 1996. And one was longed periods. The weather on all trips was rela­ noted between Isla Margarita and Tobago, 10°58'N, tively clear, sunny and breezy, except for periodic 61 °52 'W, on 27 December 1997. Each bird was rain showers during part of a day in the vicinity of alone and out of sight of land. These fast-flying, Tobago. While at sea, the ship's crew periodically dark, small seabirds never followed the ship but supplied me with coordinate data. twice made close approaches. Although the species nests on Little Tobago Island and was RESULTS AND DISCUSSION eagerly sought, we failed to note it on any of our visits to Tobago, although we passed east of Little The following accounts highlight the most Tobago on 7 March 1997 and again on 28 Decem­ significant observations for 16 species of wintering ber 1997. seabirds identified at sea during the cruises. Wilson 's Storm-Petrel (Oceanites oceanicus). Cory's Shearwater (Calonectris diomedea).­ -TI1is species was seen much less frequently than We observed three individuals during the cmises, Leach's Storm-Petrel and was not noted at all west all on the afternoon of 27 Febntary 1997. Two indi­ of Isla Margarita. Two individuals were closely viduals were observed at 10°59'N, 62°29'W, north observed at 11°20 'N, 61 °02 ' W as they pattered on of the Paria Peninsula of Venezuela. This obser­ the surface of the sea within sight of the northern vation represents the first sight record of Cory's tip of Tobago, west of Charlotteville, on 8 January Shearwater in Venezuelan waters (S. L. Hilty pers. 1996, and two individuals were closely observed comm.). The third bird was observed at 11°11 'N, pattering on the surface of the sea at 10°32 'N, 6l 0 03 'W, west of Tobago and within distant sight 60°48'W, east of Manzanilla, Trinidad, at dawn on of the island. Although previously recorded from 31 December 1997. The high count was 18 birds in Trinidad (ffrench 1991), this observation repre­ the Columbus Channel on 4 March I 997. There are sents the first for Tobago. All three individuals a few previous sight records from Tobago, which cruised low to the water, zigzagging to catch the ffrench (1991) regarded as hypothetical. From our wind off the waves and heading generally south­ experience it would seem that the Columbus Chan­ eastward. The first two crossed our bow and were nel would be an auspicious area in which to search in view for about 1min; the third overtook the ship for both species of storm-petrels. from behind and stayed in our vicinity for several Leach's Storm-Petrel (Oceanodroma leuco­ minutes, affording us close views, before gradually rhoa) .-Often seen within sight of land, this species drifting off to the southeast, toward Trinidad. All was most frequently spotted as widely separated three birds were the size of a Ring-billed Gull (Larus pairs, less frequently in loose flocks of up to 12 delawarensis). They were uniformly smoky brown birds, and least often as single individuals. It was above and immaculate white below with no obvious most common in the Columbus Channel between contrast between the head and upperparts and no Trinidad and Venezuela. The species was thinly prominent white band at the base of the tail as in and evenly distributed (average of 1/hr) at sea from Greater Shearwater (P. gravis). On all three birds Bonaire to Trinidad, at sea east of Trinidad, in the we saw the yellow bill, a diagnostic feature of this Columbus Channel, and in Galleon's Passage be­ species. Harrison (1983) shows the range of this tween Trinidad and Tobago. It was absent south­ species to be just outside the arc of the Lesser An­ east of Trinidad in an area characterized by the tilles, so it would not be unusual to find a few indi­ muddy outflow of the Orinoco River, sharply de­ viduals at the extreme western edge of their normal fined by colour and extending for several hundred Seabird Distribution in the Southern Caribbean 107 km seaward from the Venezuela coast. In contrast outflow. We noted that Masked Boobies were more to our lack of sightings, three of the four known common in the western Caribbean and were scarce Venezuelan specimens were taken at or very near from Isla Margarita eastward. We also noted that the mouth of the Orinoco Delta, and the fourth was the white morph of the Red-footed Booby was taken just northward, at the mouth of the Rio San dominant from Isla Margarita westward (roughly Juan in the Guif of Paria (S . L. Hilty pers. comm.). 50:1) whereas the brown morph was dominant During two passages ( J 3 January 1996 and 6 March farther east (roughly 10:1 ). High counts of all 1997) east ofManzan1lla, Trinidad, and out of sight species were made on 6 January 1996, during a full of land (roughly 10°30'N, 59°30'W), as many as 12 day at sea between Bonaire and the coast of Vene­ i11dividuals of this species were captured by hand zuela: Brown Booby, 2800; Red-footed Booby, 457; on the upper decks of the ship after striking the and Masked Booby, 14. superstmcture during the night (photographs ob­ Magnificent Frigatebird (Fregata magnifi­ tained). The high count was 122 birds on 4 March cens) .-We never saw this species out of sight of 1997 in the Columbus Channel. land. It was commonly seen near Cura9ao, Bonaire, Red-billed Tropicbird (Phaethon aethereus) .­ Isla Margarita, and Trinidad and Tobago but was This species was seen on every daylight passage absent from the Orinoco River outflow and the around Little Tobago, with greatest numbers al­ Columbus Channel. Large numbers were noted over ways seen in the vicinity of the nesting areas on St. Giles, where they breed (ffrench 1991 ). tl1e eastern side of the island, as on 7 March 1997 Great Skua (Stercorarius skua}.-The occur­ aud 28 December 1997. Their numbers diminished rence of this species in the southern Caribbean was sharply away from Little Tobago, with the south­ a surprise; although there are several sightiugs of ernmost observed at I J 0 09'N, 60°27'W, southeast unidentified skuas in the Caribbean (e.g., Raffaele of Little Tobago and due east of Scarborough, To­ et al. 1998), the only previous southern Caribbean bago. Away from Tobago, we observed only a records of this species were from Belize (Howell single individual at 1 I 0 32'N, 62°48'W, between and Webb 1995) and two sight records (presumably Bonaire and the coast of Venezuela, on 7 January of this species) near Chichiriviche, Falcon, Vene­ 1996. The high count was 43 birds, observed by a zuela (S. L. Hilty pers. comm.). On 7 January 1996, land-based group from our ship at Little Tobago ou as we sailed southeastward from Bonaire toward 7 March 1997. the Venezuelan coast at ll 0 15 'N, 62°38'W, we Boobies (Sula spp.).-These were the most spotted a lone, brown, gull-like bird ahead stand­ abundant birds seen at sea in the southeastern ing atop a patch of bright yellow Sargassum . It Caribbean. We saw them from first light till last, remained standing as the ship passed within 15 m near shore as well as far from shore, with almost of it. We recognised it as a sima by the combi­ equal ratios of adults to immatures. On all tl1ree nation of its massive chest, heavy hooked bill and trips, of any 100 boobies observed, the species short tail. The rusty feathering on the head, neck, ratio was approximately 80 Brown Boobies (S. leu­ and back and the lack of a pale collar were con­ cogaster) to 20 Red-footed Boobies (S. sula), with sistent with a Great Skua rather than South Polar an occasional Masked Booby (S. dactylatra). Only Skua (C. maccormicki). The latter species is cold on St. Giles (offnmihem Tobago) and Little Toba­ greyish-brown with a conspicuous pale collar. The go did we see any boobies ashore. As gulls do in only credible records of South Polar Sku a from the other oceans, boobies congregated in the air near region were a sighting at Icacos Point, Trinidad, on fi shing trawlers. We saw such clouds of boobies 13 July 1980 (Manolis 198 J) and a specimen from on all three cruises, and around them we generally Zulia, Venezuela (S. L. Hiltypers. comm.). found jaegers (Stercorarius spp.) as well. Boobies Several hours later, at 11°02'N, 61 °54 'W, we were common everywhere in the main Caribbean noted a flock of approximately 100 Brown Boobies basin but were absent from the Gulf of Paria, the resting on the sea ahead; they took to the air indi­ Columbus Channel, the open Atlantic (except in the vidually as we passed. The last seven birds of the vicinity of northern Tobago), and the Orinoco River flock were Great Skuas, flashing prominent white 108 MURPHY wing patches on both surfaces of the wings and boobies or resting on the surface of the sea with appearing uniformly reddish-brown without a pale flocks of boobies. They were usually solitary, al­ collar. One sima dashed at a booby in front of our though we could frequently spot other jaegers in bow, grasped the secondaries of the booby's left the far distance. Individuals of this species some­ wing and bore it down to the surface, directly in our times rode the aerial bow wave of the ship or fol­ path; moments later both birds took to the air as the lowed closely behind, offering excellent oppor­ ship closed on them. The skua pursued the booby, tunities for close comparison with illustrations in which disgorged a small fish that was retrieved by Olsen and Larsson (1997). Besides the large num­ the skua. Additional sightings included one at bers seen between Bonaire and Isla Margarita, as 10°56'N, 62°44'W, between Isla Margarita and To­ many as 20 Pomarine Jaegers per cruise were ob­ bago, on 8 January 1996, and another seen by Rich­ served in the Columbus Channel. This species was ard Coles between Isla Margarita and Tobago on observed in all seas around Trinidad and Tobago 3 January 1999. except for the Orinoco River outflow. On 13 January Jaegers (Stercorarius spp .).-Although Har­ 1996, we observed several individuals of this spe­ rison's (1983) range maps show the Caribbean as cies chasing Laughing Gulls (Larus atricilla) in the being devoid of jaegers, one of the surprises on vicinity of Soldado Rock (off southwestern Trin­ these cruises was the large number of jaegers seen. idad) and later observed an adult light-morph Pom­ Adults were few, being outnumbered at least 100: 1 arine Jaeger resting in the Gulf of Paria within I km by immatures. On our 1996 cruise, before the au­ of Port of Spain, Trinidad. Our high count was 525 thoritative work by Olsen aud Larsson (1997) be­ birds on 10 March 1997, during an ali-day passage came available, we attempted to identify immature between Isla Margarita and Bonaire. · jaegers by use of National Geographic Society Although less common than the previous spe­ (1987), Hanison (1983), Kaufman (1990) and Rob­ cies, the Parasitic Jaeger's distribution was similar bins et al. (1983). These texts illustrated only a few to that of the Pomarine Jaeger. We observed it on of the many plumages of both light and dark all three cruises, often in the company of Pomariue morphs, so we were able to identify only a handful Jaegers and often within sight of land. For example, of the immature jaegers. Our ability increased dra­ while moored at Pampatar, Isla Margarita, we ob­ matically with the knowledge obtained from the served four Parasitic Jaegers harassing Brown superb colour illustrations in Olsen and Larsson Boobies (Sula leucogaster) within the harbour on (1997). 26 December 1997. Parasitic Jaegers were observed Jaeger sightings were far more numerous in the sparingly around Trinidad and Tobago (three to area roughly 1O-l2°N by 65-67°W, between Bon­ four seen during each circumnavigation) and were aire and Isla Margarita and south of Aves de Barlo­ more common on the Caribbean side than on the venta, Islas las Aves, Isla Blanguilla, Islas los Atlantic side. Unlike the Pomarine Jaegers, this Rogues, Isla la Orchila, and Islas los Hermanos and species did not follow the ship. Two were observed northwest of Isla Ia Tortuga, than they were any­ in the Columbus Channel on 4 March 1997. The where else in the southem Caribbean. Jaegers were high count was 52 birds on 10 March 1997, during frequently seen harassing boobies; the concen­ a passage between Isla Margarita and Bonaire. tration of jaegers in that area might be attributed to The Long-tailed Jaeger was the least common the high number of boobies that nest and feed species of jaeger on all three cruises. Although we there. On all three trips, of any 100 jaegers ob­ saw only one adult, the unique, buoyant flight style served, the species ratio (of those identified to of this species enabled us to identify it at any dis­ species) was approximately 90 Pomarine Jaegers tance. All sightings were during passages between (Stercorarius pomarinus) to 8 Parasitic Jaegers Bonaire and Isla Margarita, with none seen any­ (Stercorarius parasiticus) to 2 or fewer Long-tailed where near Trinidad and Tobago. TI1is species fol­ Jaegers (Stercorarius longicaudus). lowed the ship closely, flying lightly like a small The Pomarine Jaeger was by far the most nu­ gull. No more than one was seen during a day. merous species observed, usually seen harassing Laughing Gull (Larus atricilla)-This was the Seabird Distribution in the Southern Caribbean 109 only species of gull observed from the ship during Landbird species.-On each trip a few presum­ the three cruises. Except for our observations of the ably migrating landbirds either accompanied the species around Trinidad and Tobago, our only ship or landed aboard it. These incidents were sightings were of apparently migrating single birds common during passages between Bonaire and far out at sea between Isla Margarita and Tobago. Tobago and less common elsewhere. Species in­ Apparently this species prefers the larger islands cluded Merlin (Falco columbarius), Gray-breasted and is only incidentally pelagic. Having witnessed Martin (Progne chalybea). Southern Rough­ the clouds of Laughing Gulls that accompany fish­ winged Swallow (Stelgidopteryx rujicollis), and ing fleets elsewhere, we found it interesting to note Bam Swallow (Hirundo rustica). their absence from such fleets at sea between Conclusions.-The unprecedented numbers of Bonaire and Tobago. The high count was 85 birds various seabird species observed during these on 8 January 1996 at 11 °2 1 'N, 60°33 'W, within sight cruises, including a few species significant distri­ of northwestern Tobago. butional records, reveal that much remains to be Tems.-A t least nine species of terns nest in learned regarding the pelagic distribution of sea­ the southern Caribbean: Large-billed Tern (Phae­ birds in the southeastern Caribbean. As seabird tusa simplex), Roseate Tern (Sterna dougallii), nesting colonies become increasingly threatened Bridled Tern (S. anaethetus), Sooty Tern (S. fus­ by human activities, quantitative studies of seabird cata), Least Tern (S. antillarum), Royal Tern (S. distribution should be conducted to further assess maxima) , Sandwich Tern (S. sandvicensis), Brown the stah1s of each species in the region. Noddy (Anous stolidus), and Black Noddy (A. ten­ uirostris). However, the only species we observed ACK.i'IOWLEDGEMENTS in the Caribbean proper on any of the cruises was Royal Tern. We observed this species widely I thank tour coordinator L. Stevenson and the throughout the region, including the Orinoco River American Birding Association for the opportunity outflow and the open Atlantic. Usually seen singly, to escort their birding groups to the southeastern it was most mtmerous at 11 °10'N 60°55'W, within Caribbean, the staff and crew of the Clipper Cruise sight of land off southwestern Tobago, where our Line for their consideration and assistance with high count was 120 on 27 December 1997. Al­ logistics and coordinates, and the many persons though Bridled and Sooty Terns and Brown Noddy who assisted me during the seabird surveys, should have been present on Little Tobago and especially J. Blomberg and J. and N. Waldron. I also other islands during our March visit, none was thank D. W. Finch, S. L. Hilty and A. R. Keith for seen from our ship. reviewing an earlier version of the manuscript. We observed Least Terns only once. On 31 December 1997, our ship emerged from the Orinoco LITERATURE CITED River and was heading northwestward toward the Columbus Channel. Between 1100-l200hr, weaver­ BOND, J. 1985. Birds of the West Indies. Collins, took and gradually passed a single-species flock of London. 256 pp. Least Tems that stretched from 9°28'N, 60°35'W to NATIONAL GEOGRAPHIC SOCIETY. 1987. Field guide 9°36 'N, 60°42'W. The birds were flying just above to birds ofNorth Ame1ica. National Geograph­ the surface of the Orinoco River's brown water in a ic Society, Washington, DC. 464 pp. band about 50 m wide. We observed no feeding, FFRENCII, R. 1991. A guide to the birds of Trinidad only an orderly array of terns in flight. We counted and Tobago. Comell Univ. Press, Ithaca, NY. the birds and, after we had left the flock behind, we 426 pp. came to the consensus that it had consisted of HARRISON, P. 1983. Seabirds: an identification about 4,000 individuals. We searched unsuccess­ guide. Houghton Mifflin Company, Bosto11. fully for other tem species, including Yellow-billed 448 pp. Terns (S. superciliaris), in the flock. Such a large HOWELL, S. N. G. AND S. WEBB. 1995. A guide to aggregation appears unprecedented. the birds of Mexico and Northern Central 110 MURPHY

America. Oxford Univ. Press. 851 pp. ROBBINS, C. S., B. BRUUN, AND H. S. ZIM. 1983. A KAUFMAN, K. 1990. A field guide to advanced bird­ guide to field identification: birds of North ing. Houghton Mifflin Company, Boston. 299 America. Golden Press, New York. 360 pp. pp. Voous, K. H. 1983. Birds of the Netherlands An­ MANOLIS, T. 1981. First sight record of South Polar tilles. 2nd ed. Foundation for Scientific Re­ Skua Catharacta maccormicki for Trinidad, search in Surinam and the Netherlands An­ West Indies. Amer. Birds 35:982. tilles, Utrecht. 327 pp. MEYER DE SCHAUENSEE, R. AND W. H. PHELPS, JR. 1978. A guide to the birds of Venezuela. Princeton University Press, Princeton, NJ. 424 Editor's note: This paper was republished with pp. permission, but inadvertently prematurely, in Sea OLSEN, K. M. AND H. LARSSON. 1997. Skuas and Swallow 50: 18-25, 2001. The Sea Swallow version jaegers: a guide to the skuas and jaegers ofthe also includes additional information gleaned from World. Yale Univ. Press, New Haven, CT. 190 the Sea Swallow database by Stan Howe. Details pp. are provided for a sighting of a Yellow-nosed Alba­ RAFFAELE, H. A. 1983. A guide to the birds of tross (Diomedea chlororhynchos) at 11 °50'N, 60° Puerto Rico and the Virgin Islands. Fondo Ed­ 55 'W (approximately 40 nrn NNW ofTobago) on 19 ucativo Interamericano, San Juan, Mexico. 247 September 1968 by W. Brackenridge, initially de­ pp. scribed in Sea Swallow 21 :36, 1972. And in Fig. 1, RAFFAELE, H. A., J. WILEY, 0 . GARRIDO, A. KEITH, the distribution of the Pomarine Jaeger in the AND J. RAFFAELE. 1998. A guide to the birds of southeastern Caribbean is mapped from records the West Indies. Princeton University Press, contained in the Royal Naval Bird Watching So­ Princeton, NJ. 511 pp. ciety database. Pp. I I 1-118 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. 11 , 2002.

A MIST-NETTING STUDY IN GUAY AGUAYARE AND THE VICTORIA MAYARO FOREST RESERVE, TRINIDAD, WEST INDIES

STEWART A. WHITE Department ofEnvironmental and Evolutionary Biology, Graham Kerr Building, University of Glasgow, Glasgow G 12 8QQ, UK

ABSTRACT.-During July-August 1999, Tconducted a mist-netting study of resident landbirds in four different forest types in southern Trinidad, West Indies: ( 1) virgin forest; forest managed by the (2) Open Range Method (ORM) and (3) Periodic Block System (PBS); and (4) mixed forest. During 728 mist net hr, 742 individual birds representing 57 species were captured at the four sites. Species richness, species diversity and capture rates were greatest in the mixed forest and lowest in the virgin forest. The avifauna of the PBS forest most closely resembled that of the virgin forest. However, given the Jimitatimls of mist-netting, further censuses are needed to adequately compare avifauna[ composition between the four sites.

R.ESUMEN.-Durante julio-agosto de 1999, estudie las aves terrestres con redes de niebla en cuatro diferentes tipos de bosque en el sur de Trinidad, lndias Occidentales: (1) bosque virgen; bosque manejado por el (2) Metodo Rango Abierto (MRA) y (3) Sistema de Bloque Peri6dico (SBP); y (4) bosque mixto. Durante 728 hr de red de niebla, se capturaron 742 individuos de 57 especies en los cuatro sitios. La riqueza de especies, diversidad de especies ytasa de captura fueron mas altos en el bosque mixto y mas bajo en el bosque virgen que en cualquier otro sitio. La avifauna del bosque SBP fue mas similar a Ia del bosque virgen. Sin embargo, dado a las limitaciones en el uso de las redes de niebla, se requieren mas censos para comparar adecuadamente Ia composici6n de aves entre los cuatro sitios.

KEY WoRDS.-bird populations, forest management, mist-netting, species diversity, species riclmess, Trinidad

Trinidad and Tobago has long been a mecca where I have initiated what will hopefully become a for both professional and amateur ornithologists. In long-term study examining species diversity in Trinidad, the Northern Range in general and the three forest types. Arima Valley in particular have been sites of inter­ P1imary forests throughout the tropics are rap­ est to scientific researchers working on birds and idly being logged. T11ere is a growing body of work other organisms since Ame1ican scientist William on the impacts of selective logging on the biodiver­ Beebe established the Simla Research station in sity of various taxa. Holloway et al. ( 1992) studied I 949. Most of the ornithological work conducted in the response of insect groups to Jogging in East Trinidad has been in the north of the island, es­ Malaysia and Willott (1999) examined moths in a pecially the Northern Range (ffrench 1991, 1998). Bornean rainforest. Wood and Gillman (1998) docu­ Little work l1as been done in soutl1ern Trinidad, mented the effects of disturbance on butterflies in

I 11 112 WHITE

TABLE 1. Forest type, locality and coordinates of four study sites in sou them Trinidad.

Census site Forest tYPe Locality Coordinates Site A Virgin Victoria Mayaro 10°11 'N, 61 °07'W Site B Open Range Method Victoria Mayaro 10°11 'N, 61 °04'W Site C Periodic Block System Victoria Mayaro 10°13 'N, 61°08'W SiteD Mixed Guayaguayare 10°08'N, 61 °05'W southern Trinidad. There have been many studies with a diversity of tree species and age classes. on the effects of logging on bird communities. The The only visible disturbance was a few narrow effects of selective logging on bird communities (<1m wide) trails cut by foresters surveying the have been studied in Borneo (Lambert 1992), Ma­ area shortly before the census. The ground was un­ laysia (Johns 1996), and in several areas of in Cen­ dulating with ridges 30+ m high, rendering the po­ tral and South America (Mason 1996, Restrepo and sitioning of net sites difficult. A stream wound Gomez 1998, Thiollay 1992, Whitman et al. 1998). through the area. These studies have found logging to have a gen­ Site B had been managed using the Open erally negative effect on tropical bird communities, Range Method (ORM). The traditional method of although the results of Whitman et al. (1988) dif­ exploitation, the ORM involved identifying andre­ fered from previous studies in finding similar bird moving any trees of marketable size and quality, species richness and abundance of individual spe­ with no thought for replacement or for the damage cies in logged and unlogged forest done to neighbouring trees during the felling pro­ This paper reports on captures from the first cess. The only control exercised in the ORM is a field season of a projected long-term study con­ girth limit for certain species (Anonymous 1991 ). ducted in the Victoria Mayaro Forest Reserve and Clubbe and Jhilmit (1992) listed several main disad­ in the Guayaguayare area in southern Trinidad. 1 vantages to this system, iucluding localised over­ compare the numbers of individuals and species cutting leading to near clearcutting in some areas, caught in different sites with respect to the effects lack of effective supervisory control, and loss of oflogging on the bird communities. full growth potential of some trees as girth limits were fixed in an era when the main technology for METHODS extraction was tl1e ox. The ORM site chosen for the census bore ob­ Study sites.-Four sites in southern Trinidad vious signs of exploitation despite not being cut for were censussed, including three in the Victoria 10 yr. Timber extraction trails >3 m wide criss­ Mayaro Forest Reserve and one in Guayaguayare crossed the area. There were substantial areas of owned by Petrotrin (Table 1). The first area cen­ Heliconia spp. and other shrubs without trees. sussed (site A) comprised virgin forest, consisti11g Furthermore, few trees appeared older than about exclusively of Mora forest dominated by Mora ex­ 20 yr. Canopy height appeared significantly lower celsa, a tall, evergreen tree (Beard 1946). In its or­ than in site A. One stream passed through the site. iginal unexploited state, the Mayaro forest covered The terrain was undulating with ridges up to 25 m 21,7 50 ha. The caT!opy was ±3 7-43 m high with reg­ high ularly spaced trees allowing few or no gaps. The Site C had been exploited using the Periodic other main canopy forming species was the Crappo Block System (PBS). In this system an area of 150- (Carapa guianensis). The shrub, field and ground 300 ha was demarcated as a block and harvesting layers were composed almost exclusively of young operations confined within this area for a 2-yr Mora seedlings. Bromeliads were the principal epi­ period. Trained silviculturalists physically marked phytes; few lianes were present (Beard 1946). trees that were to be removed. Girth limits were not During this study the forest appeared pristine used and care was taken in selection of trees to be ------

Mist-netting Study in Southern Trinidad 113 felled (Clubbe and n1ilmit 1992). Extraction meth­ rately reflected the topography of the sites. ods were designed to minimise damage to the for­ On each day, five 2.5 x 18 m Colonsay mist est; thus, a limited amonnt of timber was removed nets were erected at a site. Four days of mist-net­ from each area (John 1998). After the 2-yr exploi­ ting were conducted at eacl1 site. Nets were erected tation period the block was closed. This provides between 0550 and 0700 and left open tmtil 1500 or ample time for the area to recover between periods 1700 in the afternoon on alternate days. All birds of exploitation. The PBS system of management captured were identified, sexed and marked with a was originally developed to maintain the quality of uniquely numbered ting to allow identification of timber being produced. For each tree felled, another recaptures. Identification was based on ffrench of the same quality is left to grow, therefore ensur­ (1991 ). Biometric measurements such as weight and ing that the genetic quality of the species is re­ length of wing, bill, head and tarsus were taken and tained. Care is taken to remove all creepers and the birds then released. The number of net hr and lianas attached to trees to be felled so that no other captures (excluding recaptures) per net hr were cal­ trees are taken down with the target specimen culated for each site. (John 1998). A byproduct of this system is that Each species caught was assigned to one of there is less disturbance to the animals inhabiting three habitat niches (Hayes and Samad 1998): (I) the forest. The PBS system has been introduced forest interior, found within the forest and rarely, if over the past 50 yr in an attempt to maintain the ever, in clearings or at forest edges; (2) forest edge, integrity of managed forests and appears to be characteristically found at the forest edge or asso­ reasonably successful. The PBS site appeared to ciated with forest clearings, but not found deep in have a diversity of tree species and age classes, the forest; and (3) generalist, found deep within the but again with many extraction trails ±3 m wide. forest, in clearings and at forest edges. There were a few small herbaceous areas lacking Statistical analysis.-Biometric data were not trees, but no large ones. Canopy height in this area analysed. The Shannon index of diversity (H' sta­ was variable. A dense understorey of Heliconia tistic) was calculated as a measure of species diver­ spp. was a noticeable feature in some areas. A few sity in each habitat (Shannon 1948). An analysis of streams passed through the area and there were variance (F statistic) and Tukey-Kramer pairwise some ridges up to ±20 m high. Both the ORM and comparisons (Soka1 and Rohlf 1981) were used to PBS management strategies are described in greater compare hourly capture rates among sites. Chi­ detail in Clubbe and Jhilmit (1992). square tests Cl statistic; Sokal and Rohlf 1981) The area in Guayguayare (Site D), surveyed at were used to compare the proportions of birds be­ the request ofPetrotrin, contained a mixture of un­ longing to tl1ree habitat categories among the four spoiled virgin forest surrounded by disturbed areas sites. of secondary forest, patches of thick, low shrub, open areas of grassland and various oil tanks and RESULTS buildings. Ridges up to 20 m high were present. There were no streams or standing water. During 728 mist net hr, 742 individual birds Study design.-censussing was conducted in representing 57 species were captured at the four July and August 1999 by mist-netting (Bibby et al. sites (Table 2). Both species richness and species 1992). lu each census site a grid of net points was diversity were greatest in the mixed forest and low­ identified, covering an area of roughly 600 m by 400 est in the virgin forest (Table 3 ). An analysis of var­ m. The grid of points superimposed over the area iance confirmed a significant difference in captures were no less than 50 m apart and points were se­ per net hr among sites (F = 19 .75, P < 0.001), with lected at random for mist nets to be erected. I had capture rates highest in the mixed forest and lowest previously found that nets on ridges in Trinidad in the virgin forest (Table 3). Tukey-Kramer pair­ capture more birds than those in low lying areas wise comparisons revealed no significant difference and on the sides of hills, so an attempt was made to in capture rate between the virgin and PBS sites ensure that the 'randomly selected' points accu- and between the ORM and mixed sites, but signifi- 114 WHITE

TABLE2. Capture rates (per 10 net hr) for forest types A (virgin), B (open range method), C (periodic block system) andD (mixed) in southern Trinidad. Taxonomy is based on American Ornithologists' Union (1988) and ffrench (1991). Habitat categories include: E =forest edges; F =forest interior; G = generalist (forest interior and forest edges).

Forest type S2ecies A B c D Habitat White Hawk (Leucopternis albicollis) 0.05 F Blue Ground-Dove (Claravis pretiosa) 0.05 E Gray-fronted Dove (Leptotila rufaxilla) 0.05 0.05 0.05 0.06 F Squirrel Cuckoo (Piaya cayana) 0.06 F Rufous-breasted Hermit (Glaucis hirsuta) 0.75 2.19 0.69 1.42 G Green Hermit (Phaethornis guy) 0.81 0.73 0.58 0.80 F Little Hermit (Phaethornis longuernareus) 0.37 0.11 0.12 F White-necked Jacobin (Florisuga mellivora) 0.10 0.06 F Black-throated Mango (Anthracothorax nigricollis) 0.05 E Ruby-topaz Hummingbird (Chrysolampis mosquitus) 0.05 E Blue-chinned Sapphire (Chlorestes notatus) 0.05 0.63 0.21 0.87 F White-chested Emerald (Amazilia chionopectus) 0.11 0.16 0.21 E Copper-rumped Hummingbird (Amazilia tobaci) 0.31 0.43 E Pygmy Kingfisher (Chloroceryle aenea) 0.05 0.10 G Rufous-tailed Jacamar (Galbula ruficauda) 0.10 0.06 G Red-rumped Woodpecker (Veniliornis kirkii) 0.06 G Streaked Xenops (Xenops rutilans) 0.06 F Gray-throated Leaftosser (Scerurus albigularis) 0.06 F Plain-brown Woodcreeper (Dendrocincla fuliginosa) 0.27 0.05 0.95 0.19 F Cocoa Woodcreeper (Xiph01ynchus susurrans) 0.05 0.11 F Barred Antshrike (Thamnophilus doliatus) 0.12 E Plain Antvireo (Dysitharnnus mentalis) 0.05 F White-flanked Antwren (Myrmotherula axillaris) 0.11 0.21 0.43 F Silvered Antbird (Sclateria naevia) 0.05 0.05 F Southern Beardless-Tyrannulet ( Camptostoma obsol etum) 0.05 F Forest Elaeuia (Myiopagis gaimardii) 0.05 0.06 F Ochre-bellied Flycatcher (Mionectes oleaginea) 0.43 0.94 0.47 0.74 F Slaty-capped Flycatcher (Leptopogon superciliaris) 0.06 F Yellow-breasted Flycatcher (Tolmomyias flaviventris) 0.05 0.12 F White-throated Spadebill (Platyrinchus mystaceus) 0.11 0.16 0.12 F Euler's Flycatcher (Lathrotriccus euleri) 0.05 0.21 F Bright-rumped Attila (Attila spadiceus) 0.12 F White-winged Becard (Pachyramphus polychopterus) 0.05 F White-bearded Manakin (Manacus manacus) 0.43 1.20 1.32 0.68 F Golden-headed Manakin (Pipra erythrocephala) 0.86 2.66 0.63 2.04 F Red-eyed Vireo (Vireo olivaceus) 0.06 G Golden-fronted Greenlet (Hylophilus aurantiifrons) 0.05 0.31 F Rufous-breasted Wren (Thryothorus rutilus) 0.11 0.05 0.05 0.31 F House Wren (Troglodytes aedon) 0.05 0.06 E Long-billed Gnatwren (Ramphocaenus melanurus) 0.16 0.12 F White-necked Thrush (Turdus albicollis) 0.22 0.47 F - --·· --- ·-- --· ------

Mist-netting Study in Southern Trinidad 115

TABLE 2 continued.

Forest type S:eecies A B c D Habitat Cocoa Thrush (Turdusfumigatus) 0.05 F Golden-crowned Warbler (Basileuterus culicivorus) 0.19 F Bananaquit (Coerebaflaveola) . 0.27 1.62 0.69 2.48 G White-shouldered Tanager (Tachyphonus luctuosus) 0.05 0.31 F White-lined Tanager (Tachyphonus rufus) 0.16 0.06 F Red-crowned Ant-Tanager (Habia rubica) 0.16 0.05 0.16 F Silver-beaked Tanager (Ramphocelus carbo) 0.31 0.05 0.12 E Blue-gray Tanager (Thraupis episcopus) 0.06 G Palm Tanager (Thraupis palmarum) 0.05 0.12 G Violaceous Euphonia (Euphonia violacea) 0.05 0.84 0.42 0.68 E Bay-headed Tanager (Tangara gyrola) 0.10 F Green Honeycreeper (Chlorophanes spiza) 0.05 0.12 F Purple Honeycreeper (Cyanerpes caeruleus) 0.16 0.05 0.37 F Blue-black Grassquit (Volatinia jacarina) 0.19 E Sooty Grassquit (Tiaris fuliginosa) 0.06 F Crested Oro12endola (Psarocolius decumanus} 0.06 E

TABLE 3. Comparison of captures, net hr, capture rate (per 10 net hr) and Shannon's diversity index (H') among four forest sites in southern Trinidad.

Site Forest type S.eecies Ca12tures Nethr Ca12ture rate H' A Virgin 21 96 185.5 5.18 2.59 B ORM 34 257 191.5 13.42 2.64 c PBS 27 162 189.5 8.55 2.86 D Mixed 39 227 161.5 14.06 2.95

TABLE 4. Number (proportion) of bird captures in forest, edge and generalist groups for four forest sites in southern Trinidad.

Site Forest type Forest interior Forest edge Generalist A Virgin 73 (0.76) 3 (0.03) 19(0.21) B ORM 144 (0.56) 35 (0.14) 78 (0.30) c PBS 123 (0.76) 13 (0.08) 26 (0.16) D Mixed 131 (0.58) 27 (0.12) 69 (0.30)

cant differences between all other pairwise com­ in the virgin and PBS forests whereas generalist binations. species were most common in the ORM and mixed Based on the number of captures of birds be­ forests. Forest edge species were most common in longing to three habitat categories (Table 4), forest the ORM and mixed forest sites. A chi-square anal­ interior species were proportionately most common ysis revealed significant differences in the propor- 116 WHITE

TABLE 5. Matrix of chi-square values comparing the bird species richness and bird abundance to be proportion of captures of birds in each habitat cat­ higher in forest edges than in the interior of old­ egory in four forests of southern Trinidad. growth Chaco forest in Argentina. In a hurricane­ damaged rainforest in Nicaragua, Will ( 1991) found Forest Foresttype capture rates at damaged sites similar to that of type Virgin ORM PBS comparable undamaged lowland rainforest. How­ ORM 13 .98b ever, most frugivores caught in the hurricane-dam­ PBS 3.11 17 .07b aged forest were species typical of forest-edge, Mixed 11.42" 0.34 14.15b forest canopy and second growth habitats; there "P < 0.01 were few captures of species typical of the forest bP < O.OOl interior. Restrepo et al. (1999) found a difference between young (<12 yr) and old (>40 yr) anthro­ pogenic forest edges in a montane tropical forest in tions of birds belonging to different habitat groups southwestern Colombia. At old edges, the number between between all pairwise combinations of for­ of fruits and bird capture rates did not vary with est types except virgin vs PBS and ORM vs mixed distance into the forest, but at new edges the num­ (Table 5). ber of fruits was higher at the forest edge but cap­ tures of frugivorous birds increased toward the for­ DISCUSSION est interior. Mason (1996) studied the response of Vene­ The effectiveness of mist nets differed mark­ zuelan understory birds to selective Jogging and edly between shaded and more open forest types. found that species colonising disturbed forests did The virgin forest and, to a lesser extent, the PBS not compensate for the diversity of primary forest forest were more shaded than the other sites, which species lost after Jogging. Similarly, a study con­ may bave affected the capture rates. Canopy height ducted in the Northern Range of Trinidad found in the virgin site was considerably higl1er than in both species richness and species diversity to be the other sites, suggesting that the nets in this site lower in an exotic Caribbean pine forest than in an were sampling a smaller proportion of the vertical adjacent broad-leaved forest (Hayes and Samad structure of the forest. The canopy was also more 1998). complete in the virgin forest and the shrub layer Although the results from this study contrast less dense than in the other forests . Consequently with most previous studies in finding lower species the virgin forest avifauna may have been under­ diversity in virgin forests, Remsen and Good (1996) sampled. pointed out that comparisons ofrelative abundance Species diversity was clearly highest in the of birds should not be made using mist-net capture mixed forest and lowest in the virgin forest. The data alone. One set of data from each forest type is virgin forest and, to a lesser extent, the PBS forest inadequate and in future field seasons I intend to were more homogenous than the other census conduct more mist-netting at the same sites and at areas, providing habitat most suitable for forest other sites of the same forest types. In addition to interior species. The ORM and mixed forests pro­ low-level mist-netting some sound recording has vided habitat for proportionately fewer forest in­ already been completed but not yet analysed, with terior species and more forest edge and generalist more to be done in the future. Point counts of birds species. The similarity in capture rates and habitat and quantitative sampling of the vegetation will use of birds between the virgin and PBS forests also be conducted to gain a clearer idea of the ef­ suggests that the PBS system maintains the integ­ fects oflogging on bird communities. rity of the forest. Previous studies comparing bird diversity in ACKNOWLEDGEMENTS virgin and disturbed forests have yielded mixed re­ sults. For example, DeCasenave et al . (1998) found I thank S. Bodnar and M. Oatham for helpful Mist-netting Study in Southern Trinidad 117

comments on the manuscript. Much of the credit dance and seasonality of birds in a Caribbean for this study must go to the members of the Bird pine plantation and native broad-leaved forest Group on the 1999 Glasgow University Trinidad Ex­ at Trinidad, West Indies. Bird Conserv. Int. pedition: I. Jaeger, J. Morris, L. Mulligan and A. 8:67-87. Phillimore. Without their hard work and good com­ HOLLOWAY, J.D., A. H. KIRK-SPRIGGS, AND V. K. pany it would not have been possible to collect the CHEY. 1992. The response of some rain forest data. I also thank S. Dayal of Petrotrin, Pointe-a­ insect groups to logging and conversion to Pierre, for arranging accommodation and permis­ plantation. Phil. Trans. R. Soc. London B sion to work on their land, Mr. Shakir of Guaya­ 335:425-436. guayare for all his assistance, and D. Chadee, D. JoHN, K. 1998. The periodic block system. Unpubl. Boodoo and D. Persad of the Forestry Division, report, Forestry Division, Port of Spain. 5 pp. Wildlife Section, for all their help. This study was JOHNS, A. D. 1986. The effects of selective logging supported by many sponsors of the 1999 Glasgow on the ecological organisation of a peninsular University Trinidad Expedition and by a personal Malaysian rain forest avifauna. Forktail 1:65- grant from The Camegie Tmst for the Universities 79. of Scotland. LAMBERT, F. R. 1992. The consequences of select­ ive logging for Bomean lowland forest birds. LITERATURE CITED Phil. Trans. R. Soc. London B 335:443-457. MASON, D. 1996. Responses of Venezuelan under­ AMERICAN ORNITHOLOGISTS' UNION. 1998. Check­ story birds to selective logging, enrichment list of North American birds. 7th ed. American strips, and vine cutting. Biotropica 28:296-309. Omithologists' Union, Washington, DC. 829 REMSEN , J. V. JR., AND D. A. GOOD. 1996. Misuse of pp. data from mist-net captures to assess relative ANONYMOUS. 1991. Forestry handbook. Forestry abundance in bird populations. Auk 113:381- Division, Port of Spain. 398. BEARD, J. S. 1946. The natural vegetation of Trini­ RESTREPO, C., AND N. GOMEZ. 1998. Responses of dad. Oxford For. Mem. 20:1-152. understory birds to anthropogenic edges in a BIBBY, C. J., N. D. BURGESS, AND A. HlLL. 1992. Bird Neotropical montane forest. Ecol. Appl. 8:170- census techniques. Academic Press, London. 183. 257 pp. RESTREPO, C., N. GOMEZ, AND S. HEREDIA. 1999. CLUBBE, C. P., AND S. JHILMIT. 1992. A case study Anthropogenic edges, treefall gaps and fruit­ of natural forest management in Trinidad. Pp. frugivore interactions in a Neotropical mon­ 201-209 in Wise management of tropical for­ ane forest. Ecology 80:668-685. ests. Proceedings of the Oxford conference on SHANNON, C. E. 1948. A mathematical theory of tropical forests (F. R. Millar and K. L. Adam, communication. Bell System Tecl1. J. 27:379- eds.). Oxford Forestry Institute, Oxford. 423, 623-656. DECASENAVE, J. L., J.P. PELOTTO, S.M. CAZJANI, SOKAL, R. R., AND F. l ROHLF. 1981 . Biometry. 2nd M. MERMOZ, AND J. PROTOMASTRO. 1998. Re­ ed. W. H. Freeman and Company, New York. sponses of avian assemblages to a natural 859 pp. edge in a Chaco semiarid forest in Argentina. WHITMAN, A. A., J. M. HAGAN, AND N. V. L. BRO­ Auk 115:425-435. KAW. 1998. Effects of selection logging on FFRENCH, R. 1991 . A guide to the birds of Trinidad birds in Northern Belize. Biotropica 30:449-457. and Tobago. 2nd ed. Comell University Press, WILL, T. 1991. Birds of a severely hunicane-dam­ Ithaca, NY. 426 pp. aged Atlantic coast rain forest in Nicaragua. FFRENCH, R. 1998. A review of the omithology of Biotropica 23:497-507. Trinidad and Tobago. Living World (J. Trin. WlLLOTT, S. J. 1999. The effects of selective log­ Tob. Field Nat. Club) 1997-1998:3-7. ging on the distribution of moths in a Bomean HAYES, F. E., AND I. SA MAD. 1998. Diversity, abun- rainforest. Phil. Trans. R. Soc. London B 118 WHITE

354: 1783-1'/90. methods of sampling in Trinidad. Biodivers. WOOD, B., AN D GJLMAN, M.P. 1998. The effects of Conserv. 7:597-616. disturbance on forest butterflies using two Pp. 119-130 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. 11,2002.

OBSERVATIONS OF THE ENDANGERED TRINIDAD PIPING-GUAN (PIPILEPIPILE), ORPAWI, INNORTHERNTRINIDAD

GAVIN D. ALEXANDER University of Glasgow, University Field Station, Rowardennan, Loch Lomond, G63 OA W, Scotland

ABSTRACT.-Relatively little is known about the Trinidad Piping-Guan (Pipile pipile), locally known as the Pawi, an endangered tropical forest species of arboreal habits. Pawi were observed at a site in Northern Trinidad in July and early August I 989 and I 99 I. Individuals or groups of up to three birds foraged in an area including vine forest, secondary vegetation and agriculture habitats. In 1989 the birds fed and spent most of their time in vine forest and were seen to feed on six food types. In 1991 they fed and spent most of their time in secondary vegetation or agriculture habitat and were seen to feed on three food types, predominantly nutmeg in the agriculture habitat. Berries of four tree species and foliage of three plant species were previously unrecorded in the diet of the Pawi. This is the first record of Pawi feeding on foliage. Foragiug took place in early morning and late afternoon, with slightly longer foraging periods in mornings. Between the 2 yr, much ofthe surrounding area afforest was felled and disturbance increased. Pawi showed no apparent effects from disturbance, but appeared to have shifted their feeding area in response to the loss of habitat. Four types of vocalisations were identified. Two of these vocalisations and wing drumming displays were recorded and are described.

RESUMEN.-Se conoce relativamente poco acerca de la Pava Rajadora de Trinidad (Pipile pipile), conocida localmente como el Pawi, una especie amenazada del bosque tropical con habitos arb6reos. Se observ6 el Pawi en un sitio al norte de Trinidad en Julio y a comienzos de agosto del 1989 y 1991. Individuos o grupos de hasta tres aves forrajearon en un area que inclufa bosque de enredaderas, vegetaci6n secundaria y areas agricolas. En 1989 las aves forrajearon Ia mayor parte del tiempo en bosque de enredaderas y comieron seis tipos de a limen to. En 1991 las aves pasaron Ia mayor parte del tiempo en Ia vegetaci6n secundaria o cultivos y comieron tres tipos de alimento, predominantemente nuez moscada en las areas agrico1as. Frutas de cuatro especies de arboles y hojas de cuatro especies de plantas no habian sido registradas previamente en Ia dieta del Pawi. Este es el primer registro de Pawi comiendo hojas. El forrajeo tuvo Iugar temprano en Ia manana y tarde en Ia tarde, con periodos mas largos durante Ia manana. Entre los 2 afios de muestreo, se destruy6 mucho del borde del bosque alrededor y aumentaron los disturbios. El Pawi no mostr6 efectos aparentes ante los disturbios, pero aparentemente cambi6 su area de forrajeo como respuesta a Ia perdida del habitat. Se identificaron cuatro tipos de vocalizaciones. Dos de estas vocalizaciones se grabaron y se describen juuto al comportamiento del golpeteo de alas.

KEY WORDS.- behaviour, Cracidae, displays, ecology, habitat, Pipile pipile, Trinidad, Trinidad Piping-Guan, vocalisations

119 120 ALEXANDER

The guans are large, predominantly arboreal impacts on P. cumanensis in S. America). birds belonging to the Central and South American Despite being protected by law in Trinidad, the family Cracidae, which includes the currassows and lack of information available on the basic biology chachalacas. The Trinidad Piping-Guan (Pipile and habitat requirements of the Pawi has inhibited pipile), orPawi as it is more commonly called in this the formulation of proper management plans for its island, is the only representative of the Cracid conservation. Accordingly, calls have been made family in Trinidad and, along with the Rufous­ by the Wildlife Section of the Trinidad and Tobago vented Chachalaca ( Ortalis ruficauda) in Tobago, Forestry Division for assistance with the collection represent the only members of the family in the of such data (James and Hislop 1988, 1997). Aside Caribbean. Like many other Cracids, the Pawi is from information applicable to conservation, there critically endangered (Collar et al. 1992). Many has long been a widescale need for basic research revisions of the taxonomic grouping of the family into avian life histories in Trinidad (ffrench 1980). have awarded and removed the species status of Thus, the primary aims of the present study were to this guan (e.g., Jacquin 1784, Sclater and Salvin co11ect and make available to the Wildlife Section 1870, Vaurie 1967, 1968, Delacour and Amadon basic data on the biology and behaviour of the 1973, Howard and Moore 1991). Most recently, Pawi and to record details of possible threats to the Strahl and Schmitz (1997) elevated the Pawi to full species. Future research into Pawi behaviour, range species rank, P. pipile, although they recommend­ use and population biology will undoubtedly re­ ed yet further review of the group and, in particular, quire the use of capture and marking of some sort, the status of P. pipile. However, irrespective of for individual identification and radio tracking. past and current scientific opinion, the Pawi has Without the time available to carry out such work long been regarded as Trinidad's only endemic ourselves, a further aim was to assess possible species (ffrench 1973) and the continuation of this methods for the captme ofPawi for this purpose. A habit is likely to maximise its prospects for survival. final aim was to collect sound recordings of the The Pawi inhabits primary and secondary low­ species. This study was carried out as part of two land and montane forests in Trinidad (James and undergraduate expeditions to Trinidad and Tobago Hislop 1997). However, habitat destruction and from the University of Glasgow (Alexander et al. hunting combined have contributed to a substan­ 1990, 1992). tial contraction of the species' range and popula­ tion, with the less disturbed montane regions be­ METHODS coming the most important refuge for the species in Trinidad (James and Hislop 1997, Temple 1999). Study Sites. -The study was carried out over Very little is known of the biology and ecology two periods in the summer months of 1989 (29 June of the Pawi, most information having come from a to 3 August) and I 991 (30 June to 4 August). Be­ study of the genus in South America (e.g., Dela­ ginning early in the 1989 period, we surveyed a cour and Amadon 1973, Strahl et al. 1997) . Its diet number of sites for the presence ofPawi, guided by consists primarily of fruits and berries, with for­ staff of the Forestry Division. Pawi had been seen aging occuring mainly in trees and rarely on the in recent years at each of these sites and the en­ ground (James and Hislop 1988). Little is known of vironmental and vegetation characteristics of each its breeding biology. And little has been done to sites had been recorded previously (James and examine the impact that hunting and habitat de­ Hislop 1988). Brief descriptions of our visits to struction are having on the species. Brooks (1999) these sites are given in the Appendix. Initial visits suggested that the species is being unsustainably to a site in the forest just inland of the north coast harvested in Trinidad, with proximity to a major city village of Grande Riviere revealed it to be ideal for (Port of Spain) and an island effect being the pri­ observing Pawi, therefore this area was used as the mary factors contributing to the vulnerability of the primary location for field observations. We did not species to both hunting and l1abitat destruction conduct a habitat survey of this study area, but a (see also Zent 1997, Begazo and Bodmer 1998 on brief description is presented here to give a reason- Observations of Trinidad Piping-Guan 121 able idea of the type of habitat in which we ob­ agrams and analyses of calls were made using a served the birds. Further details are given by James Kay 5500 Sona-Graph. ln 1991, a video camera was and Hislop (1988). used to make reasonable video recordings of the The site at Grande Riviere centred around a birds (available from the author). The area ofland at small hill in the forest at an elevation of 60-85 m. On Grande Riviere within which the birds were ob­ the hill was a house and garden with an assortment served was estimated from an aerial photograph of of small sheds and outbuildings, around which was the area. All Pawi food types were either identified a cleared, relatively open area with only grass and in the field or taken to the National Herbarium, a few planted fruit trees including mango (Man­ University of the West Indies, for identification. gifera indica; Anacardiaceae), pomme cytherre Three variations of capture method were consid­ (Spondias dulcis; Anacardiaceae), pomerac (Syzy­ ered for evaluation while we were in the field, all gium malaccense; Myrtaceae), banana and plantain ultimately by means oflarge mist nets: attraction to (Musa spp.; Musaceae), nutmeg (Myristica frag­ nets by playback of calls, attraction with decoys, rans; Myristicaceae), pawpaw (Carica papaya; and mapping of regular flight paths. Caricaceae), avocado (Persea americana; Laura­ Whenever possible, we sought information on ceae) and citrus (Citrus sp.; Rutaceae). Between the Pawi from local people. This was designed as the village and the hill (1 km) and around the slopes much to gain an insight into peoples' attitudes to­ of the hill were abandoned and overgrown plan­ ward the bird as to collect useful information on tations of cocoa (Theobroma cacao; Sterculiaceae) distribution, habits and hunting pressures. This and coffee (Coffea arabica; Rubiaceae) and sec­ was conducted on an ad lib basis, depending on ondary forest, with few stands of what appeared to the situation in which we spoke to people, and did be natural primary forest. To the SE of the house not follow a standard set of questions. Information was an area of cecropia trees (Cecropia sp.; Cecro­ gained from such conversations is included under piaceae) 3.5-4 m high, beyond which lay a long the relevant headings below. stand of tall forest trees, heavily overgrown with epiphytes and vines. Tall trees were also present RESULTS around the NW side of the hill. The vegetation in the surrounding hills consisted of primary forest. Diurnal activity patterns.-Sightings of Pawi T11ree observers spent a total of 10 days at this were made in fewer than half of the mornings and site in 1989 (1 0 July to 3 August), and four observ­ afternoons spent searching in 1989 (41 %), com­ ers spent 18 days at the same site in 1991 (30 June pared with a majority of mornings and afternoons in to 4 August). The following details of sightings are 1991 (84%; Table 1). Morning searches (first light all from this locality. to midday) were more successful than afternoons Observations took the form of daily watches, (midday to dusk) in both years, but this difference beginning in the early morning (around 0530-0600 was greater in 1991. Differences in the success rate in 1989, and from 0415, just before first light, in between years may have been influenced by the 1991 ). Observers were stationed at various points earlier morning start times and the larger observer around the centre of the study area, where good group in 1991 . views were available or where Pawi were regularly Morning sightings were generally of longer seen. When Pawi were in view, observations were duration than afternoon sightings in both years continued for as long as possible, following birds (Table 1). This difference was greater in 1991. Pawi into the forest until out of sight. Where birds were were most often seen in early morning (usually until not in view, searches continued throughout the around 0730-0830) and late afternoon (from around day. Feeding sessions were measured from start to 1600-1700), with very few sightings through the finish of feeding of groups or individual birds. middle of the day. Tape recordings of vocalisations and display Observations of Pawi were of both single indi­ sounds were made using a basic hand-held tape­ viduals and groups. At no time during the 2 yr did recorder with sep

TABLE 1. Number of days spent looking for Pawi, TABLE 2. Numbers of days Pawi observed foraging, success rate (days observed) and duration of ob­ earliest and latest observations (time of day) and servations (hr) at Grande Riviere. range of foraging time (hr) at Grande Riviere.

Yr /Variable Morning Afternoon Yr/Variable Morning Afternoon 1989 1989 Days searched 9 8 Days observed 4 3 Days Pawi observed 4 3 Earliest foraging time 0610 1715 Duration of observations 5.23 2.70 Latest foraging time 0826 1850 Min 0.85 0.35 Range of foraging time 2.27 1.58 Max 1.80 1.78 1991 Mean 1.30 0.90 Days observed 8 6 1991 Earliest foraging time 0555 1615 Days searched 16 16 Latest foraging time 0810 1814 Days Pawi observed 16 11 Range of foraging time 2.25 1.98 Duration of observations 22.28 4.57 Min 0.33 0.02 Max 3.02 1.05 both years (Table 2). Morning feeding began at the Mean 1.38 0.40 earliest around half an hour after first light (first light approximately 0520), with the afternoon feed­ ing period ending a little before or at dusk {dusk rate individuals, iu different parts of the study area approximately 1850). On any particular morning or at the same time. afternoon, the duration of the period in which the Birds were first seen either flying to or already Pawi were clearly seen to be feeding ranged from in trees within the vicinity of the hilltop area. The only a few min to over I hr, averaging around 30-40 only exceptions to this were occasional glimpses of min (Table 3). Without means of tracking birds display at first light. Activities included calling and more efficiently and identifying individuals as they display, feeding, preening, perching or resting and moved around and between trees, the feeding occasional bouts of agonistic behaviour between bouts we observed were generally short and it was individuals. With the exception of early morning not possible to gain a more accurate measure of display activities, these behaviours were inter­ actual foraging durations within the ranges given spersed throughout our observations. It appeared here. The nonnal durations of morning and after­ from the usual direction of flight at the end of mor­ noon feeding periods were probably closer to the ning sightings that Pawi retired back to the shelter maximum feeding bouts seen, around 1 hr or more of larger, vine-covered trees around the southeast­ (Table 3), although they may well be closer in dura­ em periphery of the study area during the middle of tion to the total range offeeding activities shown in the day. The few sightings that were made during Table 2. The impression was that feeding periods this time were of birds resting in trees (see Cumaca carried on for somewhat longer in mornings than sighting, Appendix), or were brief views of flying afternoons. birds. The area in which all sightings were made at Pawi fed in different parts of the study area Grande Riviere, on and around the hilltop, covered during the 2 yr. In 1989 they frequented the forest between 2.2-2.5 hectares. trees around the margins of the secondary forest Foraging and diet.-Pawi were observed feed­ on the hill, whereas in 1991 they spent the majority ing during all sightiugs in 1989 and on eight morn­ of their time on the hilltop in and around the plant­ ings and six afternoons in 1991, totalling 11.45 hr ed trees. (33% of all observed activities). Feeding took place A total of eight food types were noted, con­ within fairly well defined periods in the morning sisting of either foliage or berries (Table 4). Of and afternoon, with the morning period longer in these, about six were seen consumed by Pawi in Observations of Trinidad Piping-Gumz 123

TABLE 3. Duration of observations (hr) at Grande volvulaceae). Although Pawi and other guans are Riviere in which feeding was an activity in Pawi. reported to descend from trees to drink water (Delacour and Amadon 1973, James and Hislop Yr I Variable Morning Afternoon 1988), we did not see this. We did not make any 1989 observations of the birds close to rivers or streams, Observations 4 3 but temporary rain pools were available at our Total duration 2.77 1.58 study site. We heard a first-hand account of Pawi Mean 0.69 0.53 drinking from the Grande Riviere River (T. Marin). Min 0.23 0.27 We saw Pawi drinklng twice, once from a hollow at Max 0.92 1.02 the base of a large tree branch and once from a 1991 bromeliad. Observations 8 6 Tn summary, the daily pattern of behaviour and Total duration 4.45 2.65 foraging activity would be as fo11ows: early morn­ Mean 0.49 0.44 ings, from just before to just after first light, were Min 0.03 0.08 spent in display activities in deep, vine-covered Max 0.49 1.15 forest at the foot of the hill. With the onset of daylight, the birds would fly up the hill to forage on berries and leaves. Feeding usually took place in 1989. In this year, fiddlewood berries (Vitex bi­ one tree, but on occasion was distributed between varicata; Verbenaceae) were eaten more frequently a number of trees of different species. During and tl1an other foods (three mornings and two after­ after feeding, birds would stop for long periods to noons). At Grande Riviere we once watched two rest or preen. Generally, the Pawi would have Pawi in a wild caimite tree (Chrysophylum argen­ disappeared out of sight by mid morning, probably eum; Sapotaceae) as they fed on leaves appearing to rest in the cover of forest trees. They would to be from a vine (Calopogoniurn coeruleurn; reappear again in late afternoon, after which a Fabaceae), but may possibly have been those of pattern of activities similar to that of the morning the tree (Table 4). would resume until near dusk. The Pawi would ln 1991, only three food types were seen to be again fly towards the larger forest trees for the consumed (Table 4) in spite of the greater number night. and total duration of observations in this year. Group size.-The number of individuals seen Nutmeg (Myristica fragrans) was most frequently together as a loose group over all our sightings in eaten (six momings and five afternoons), followed all locations varied from one to three in both years, by fiddlewood (Vitex divaricata; Verbenaceae) averaging 2.1 in 1989 and 1.4 in 1991. The majority berries (three momings and one afternoon). Only of the first year's sightings were of two birds, on one other occasion in 1991 did we see another whereas more than half of the sightings in 1991 type of food consumed. When feeding on nutmegs, were of single birds. L. Marin, on whose property Pawi consumed only the fruit kernel, including the we observed the birds at Grande Riviere, reported red outer covering of mace, which they plucked larger groups around the same hilltop in previous from the open yellow fruit. A single faecal sample years, generally around four birds until 1988, when was collected in 1991, which was composed almost this fell to two. The group frequenting the area in entirely of the seeds offiddlewood berries. 1990 numbered around eight. The area in which L. Other foods which were reported to us by local Marin saw birds was similar to that in which we people as being consumed by Pawi were acurel canied out our daily observations. (Trichilia trinitensis; Meliaceae) berries and ripe Social behaviour.-Birds seen in twos or coffee beans. threes maintained a loose grouping while either We saw Pawi on the ground on several occa­ foragi11g or moving through the trees. Contact ap­ sions, including an instance when two birds were peared to be maintained visually, judging from the clearly feeding on leaves (Ipomoea tiliacea; Con- absence of contact calls which could be heard 124 ALEXANDER

TABLE 4. Plant items in the diet ofPawi in 1989 and 1991 at Grande Riviere and the frequency (number of occasions fed upon) with which each was observed eaten.

Y r I Local name Scientific name (family) Part eaten N 1989 Wild potato vine Ipomoea tiliacea (Convolvulaceae) foliage 2 Vine Calopogonium coereleum (Fabaceae) foliage 1?a Wild caimite (tree) Chrysophylum argenteum (Sapotaceae) foliage 1? · Obie (tree) Trichilia trinitensis (Meliaceae) fruit Fiddlewood (tree) Vitex divaricata ( Yerbenaceae) fruit 5 Lapine (tree) ? fruit Cajuca (tree) Virola surinamensis (Myristicaceae) fruit 1991 Nutmeg Myristicafragrans (Myristicaceae) fruit kemel 11 Fiddlewood (tree) Vitex bivaricata (Yerbenaceae) fmit 5 Bird vine or varge (unidentified epiphytic vine) foliage "feeding probably on the vine rather than the tree (see text) from more than a few m, although when birds were during observations (Fig 1). This call was made by in close proximity to each other vocal contact was birds both when they were alone and in groups. used (see below). Agonistic bouts were usually On two occasions a low, duck-like quacking or brief and generally appeared to be mildly aggt·es­ croaking call was heard (Type 2). One instance of sive events, where two birds would appear to jostle this call was heard in association with the "pyoo" for position on a branch with crests raised. How­ call and preceded the violent encounter described ever, one of these occasions escalated into a fairly above, both calls being produced with increasing violent attack in the lower branches of a nutmeg frequency and intensity over a period of 8 min tree, with two birds engaging in a brief aerial fight prior to the attack. The croaking call was also heard and one being thrown to the ground from about 2 from one of a group of three birds and was pre­ m high. On two or three occasions these actions ceded by several single, ascending whistles and tail may have been related to courtship. However, such movements from a different member of the group. observations were infrequent and difficult to in­ This whistling call (Type 3) was composed of a terpret. single whistle, rising through the same range of Calling and display.-In 1989, although we pitch when repeated. It was not heard on any other had heard many descriptions of the Pawi 's wing occas10n. drumming display and the piping calls for which the The loudest of the four calls (Type 4) was only species is known, we were unsuccessful in heating heard shortly before first light, between 0440 and or seeing either of tl1ese behaviours. In 1991, 0523 . This piping call consisted of a seties of three however, we heard four distinct types of calls of to five ascending whistles, the second and sub­ which two were recorded, and both heard a11d sequent whistles beginning at a slightly lower pitch observed the wing drumming display, all at Grande than the end of the preceding ones (Fig 2). Each Riviere. series lasted on average 4.9 seconds (n = 16 calls). The most frequently-heard call (Type 1) was a What sounded like the same bird was heard to thin, quiet "pee-oo" or "pyoo", which we heard make this call five times in 5.3 min, interspersed repeated often when we were within close range of with one drumming display (a different bird) and the birds, usually when they were in nutmeg trees. followed by calls from other individuals. Wing Single notes were characterised by a high degree of drumming displays always occurred at the same variation in pitch and structure, which was audible time and location as piping calls, during darkness Observations of Trinidad Piping-Guan 125

4

kHz

QL______------2 2 seconds Fro. I . "Pee-oo" or "pyoo" calls (type 1), showing characteristic variation.

4

kHz

2

0~------~~--~~------4 6 a SjjCOnds FIG. 2. Piping or ascending call (Type 4). This example probably lacks the fainter notes at the beginning and end as a result of background forest noise.

4

2 3 4 second3 FIG. 3. Wing drumming. This pattern of beats was very consistent in all of the recorded examples. 126 ALEXAI"'DER or at first light, between 0440 and 0527. Observa­ have dull white or cream eggs with brown or dark tions were made from directly below the birds in red markings, although both species usually have some cases, which allowed sight against the sky. tl1eir nest on the ground (ffrench 1980). The display consisted of a gliding flight between In years prior to 1989 at Grande Riviere, juve­ tall treetops, in which the wings were set only half nile Pawi about three-quarters of the adult size were open to produce a loud, dry rattling or drumming seen around mid August, followed by an increase sound. This sound followed a regular pattern, in numbers of the birds (L. Marin pers. comm.). On beginning with a single loud clap, followed by four 4 August 1991 we observed two juvenile Pawi to six 'introductoty' claps, and then two long about half to three-quarters of adult size. They were bursts of rapid drumming (Fig 3). The frequency of similar to adults in colour, but with brown rather beats doubled after the introductory claps, increas­ than near-black plumage and fewer white markings ing in frequency over the first long burst. After a on the head and wing coverts. They were accom­ pause of around 0.2 sec, the second burst lasted panied by one adult and flew as well as adults. about as long as the first, but this time decreasing Habitat changes between 1989 and 1991.­ slightly in beat frequency. Displays averaged 62 Between the 2 yr of this study, substantial environ­ beats over 2.8 sec (n = 7 displays). At the end of mental change took place in the locality of the each glide the drumming ceased and the bird study site at Grande Riviere. Most noticeably, the extended its wings, flying strongly upwards to old track into the forest had been bulldozed to regain height and alight in another treetop. The double its original width, and bulldozers and trucks distance over which this display was performed were operating along it. This was the start of a gov­ varied between roughly 30-50 m and was most ernment agricultural expansion scheme to provide frequently performed back and forth across the easier access for people to lands being brought same stretch of track in deep vine forest. Only the back into cultivation after many years of abandon­ latter ascending flight varied in length. On one ment. 24 km of roads were planned, either new or occasion a single bird perfmmed this display four upgraded from tracks, to extend into the forest from times in succession between three tree tops over 13 this access point. Walks along the road revealed a min. substantial quarry where the forest had been Piping cal1s and wing dmmming were always stripped away for road gravel extraction. The ridge performed at a location in tall, vine-covered forest close to the southeast of the hill had been com­ trees, 2-300 m from the hilltop. Only one example of pletely stripped of its dellSe sta11d of tall, vine­ each (on different days) was heard on the h111 where covered trees and had been planted with banana, the birds generally foraged. All occurred between plantain and other crops. This stand was where we 27 July and 4 August 1991. Wing-dmmming had l1ad most frequently seen Pawi in 1989. Only a not been heard at this site since I 988 by resident L. single tall tree remained, a fiddlewood, which the Marin. Pawi frequently used to perch or to feed in I 991. Reproduction.-ln 1989 we did not encounter For the duration of our observations in 1991 any signs of the nests or young of Pawi, nor did we there was constant disturbance in the area from the meet anybody that could give us descriptions of noise and movement of heavy vehicles. Bulldozers these. Jn 199 I, one local resident described a Pawi generally started up every morning around 0630 nest that he had seen i11 the forest as being situated and passed within yards of Pawi food trees, some­ "not very high up" in a tree. The eggs he described times close enough to blow exhaust fumes into the as chalky white with black or dark spots, but he had trees while they were occupied by the birds. Each never seen the chicks. The eggs of other species of morning, groups of gardeners passed by on their guan are white or cream, but with no markings other way to their plots, on some days accompanied by than staining from leaves (Delacour and Amadon trucks full of young plantain and banana plants, 1973, Estudillo-Lopez 1979). This nest may there­ and even the occasional 'maxi taxi' full of people. fore have been that of a Black Vulture (Coragyps Yet despite the increased noise and activity levels atratus) or Turkey Vulture (Cathartes aura), which caused by the road-building machinery and pedes- Observations of Trinidad Piping-Guan 127 trian traffic, the Pawi seemed relatively oblivious to nutmegs and to scratch around on the ground for the disturbance. They seemed no more wary than food. He had on one occasion left nutmegs under they had been in 1989 and appeared even more a regular feeding tree and seen at least one bird confident than before. come down to feed on them. We did not try this, Although a proportion of the land being but on a number of occasions we saw nutmegs cleared for this project was abandoned and over­ being knocked out of trees by Pawi moving grown plantation (i.e., secondary forest), this type amongst branches, after which the birds flew to the of habitat is still of value to these birds, with foods ground below the tree. However, the vegetation such as coffee berries and nutmegs available to was such that we could not see whether the birds them. That the Pawi exist in areas of similar vege­ fed on the ground. tation deeper into the forest was confilmed by two local men who we frequently spoke to and who DISCUSSION regularly worked a plot of land in this area. Hunting.-We found no direct evidence of These observations represent the habits of hunting, although this is not surprising as it was Pawi in the Grande Riviere area in July and early illegal. However, nearly all local people that we August. At other times of year, and possibly at spoke to were well aware ofthe species as a favour­ other locations, their patterns of behaviour, move­ ite hunters' quarry. Some men showed obvious ments and diet may differ (Delacour and Amadon enthusiasm when talking of hunting Pawi and often 1973). In these months, the birds fed in the early described their favourite recipes for the species. morning and late afternoon, resting through the We concluded therefore that hunting was still middle of the day. Display activities occurred in widespread and common. near-darlmess before morning feeding. Capture methods.-Piay-back of tape recorded Feeding patterns of the Pawi shifted between calls was abandoned after 1t was found impossible different parts of the study area at Grande Riviere. to make recordings of sufficient quality, due to In both years there would be two or three consec­ forest noise and inadequate equipment. utive days in which the birds were either not seen, Life-size decoys ofPawi were constructed from or were seen only briefly and then not feeding. polystyrene and painted. These were positioned in Having a diet primarily of fruit, it would seem nat­ trees in the birds' regular feeding area and moved ural that they would move around their forest envi­ around over a period of a week. The Pawi did not ronment, depending on where trees happened to be show any obvious interest in the decoys, although fruiting. This type of behaviour is typical for other they were plainly visible. guans (Schwmiz, in Delacour and Amadon 1973: Through our daily observations of the Pawi 60). within the same area we became acquainted with With the exception of cajuca berries (Virola some of their movements. That they visited certain surinamensis; Myristicaceae), none of the food trees regularly in which to feed was apparent, at types identified i11 this study have previously been least within the short petiod during which our field recorded (James and Hislop 1988). That Pawi fed on observations lasted. However, they did not main­ nutmeg was well known amongst local residents tain regu Jar flight paths or maintain the same sched­ that we spoke to in a number of locations. No ule every day. Pawi would feed intensively on one previous record has been made of Pawi feeding on tree or patch of trees for a day or two and then foliage, but it is likely that further study will reveal move to another patch nearby for a period. In spite many more food types in the diet of these birds ( cf. of this, we were confident that by identifying Zent 1997). favoured food trees and setting nets around them, Previous research lms shown that secondary capture would be possible. forest is of value to Cracids, and can exceed pri­ Another possible capture method emerged in mary forest in the number and density of food plant discussions with L. Marin, who told us that Pawi species. ln the Venezuelan Amazon, this has been will come down to the ground to feed on fallen shown to be pat1icularly true for P. cumanensis 128 AlEXANDER

(Zent 1997). Visits to other locations in Trinidad trast, he found that the response to playback of the and discussions with local residents highlighted calls was extremely good, with birds attracted to the that secondary vegetation, such as overgrown vicinity of the sounds, but generally only at or coffee, cocoa and citrus plantation, provides good above tree-top level. Although we did not investi­ feeding habitat for Pawi. The primary disadvantage gate the effectiveness of baiting for attracting Pawi, with such areas is that they often lie in closer this method may also have potential as a capture proximity to human settlements than primary forest method. and birds therein are thus at greater risk from The caretakers of the study site at Grande hunters. That huma11 disturbance is the crucial Riviere lived on the site. That the Pawi have sur­ factor in determining whether Pawi survive in other­ vived here, so close to an area of human settlement, wise suitable habitat was emphasised by James and is due primarily to the interest this couple have in Hislop (1988, 1997). From the observations made these birds and their opposition to any hunting of during this study, it would seem that disturbance in them on their land, in spite of the loss of some of the form of noise and human/vehicular traffic per se their crops. This protective attitude towards their are not enough to dtive the birds from suitable hab­ indigenous fauna should be applauded and fos­ itat. Therefore hunting would seem to be the pri­ tered as much as possible amongst rural residents mary cause. It was apparent from a number of local throughout Trinidad residents with whom we spoke that Pawi are still regarded as a desirable food item and that hunting ACKNOWLEDGEMENTS would probably continue for this reason alone. The Forestry Division at the time lacked sufficient re­ The field work for this study was conducted sources to adequately protect the species (C. by the author and L. Brown, G. Gilbert, E. James, pers comm.), therefore the risk of being Cunningham, C. McCaul and M. McCormack of caught hunting was minimal. In the study area and Glasgow University. Thanks go to C. James, head the nearby areas of forest under development there of the Wildlife Section of the Forestry Division in is new potential for conflict over crops and an Trinidad, for advice and assistance in this project, increased risk of hunting from more people gaining and to her staff, B. Wiltshire, I. Farrier and R. Singh easier access to the forest. The survival prospects for their knowledgeable guidance in the field. The for the birds here have probably been reduced. help of staff at the National Herbarium and Depart­ Numbers of Pawi appear to have fluctuated at ment of Zoology, University of the West Indies, is the Grande Riviere site over the years, with the gratefully acknowledged. Thanks go to P. Slater of presence of young birds and calling/display activ­ the University of St. Andrews for use of a Kay 5500 ities apparently being associated with the number Sona-Graph for call analyses. Special thanks must of birds in the vicinity. These changes may be the go to Leo and Theresa Marin, of Grande Riviere, for result of mmual variation in fruit crops or may their kind hospitality during this study, and for reflect actual local population changes-either nat­ their enthusiasm for and protection of the Pawi on ural or otherwise. Simple, standardised surveys of their small piece of land. the state of Pawi populations in this and other areas, at regular intervals, are needed. LITERA TIJRE CITED Although we did not make any significant progress in our assessment of capture methods, we ALEXANDER, G. D., L. BROWN, ANDG. GILBERT. 1990. demonstrated that decoys alone are useless in Distribution and habits of the Trinidad Piping attracting birds to mistnets. If used in conjunction Guan. Pp. 39-59 in Report of the Glasgow with playback, they may l1ave been more effective, University Exploration Society Expedition to as postulated by Schwartz (in Delacour and Ama­ Trinidad and Tobago, 1989 (R. Downie, ed). don 1973:60-61). Schwartz described play-back of University of Glasgow, Glasgow. wing drumming, at least without a visual stimulus, AlEXANDER, G. D., E. CUNNINGHAM, C. MCCAUL, as being of little use in attracting guans. In con- AND M. McCORMACK. 1992. Conservation- Obsen,ations of Trinidad Piping-Guan 129

related observations of the Trinidad Piping SCLATER, P. L. AND 0. SALVIN. 1870. Synopsis of Guan (Aburria pipile pipile). Pp. 6.1-6.9 in the Cracidae. Proc. Zoo!. Soc. London 504-544. Report of the University of Glasgow Con­ STRAHL, S. D., S. BEAUJON, D. M. BROOKS, A. J. servation Expedition to Trinidad and Tobago, BEGAZO, G. SEDAGHATKJSH, AND F. OLMOS 1991 (R. DoWJ1ie and M. Reilly, eds). Uni­ (EDS). 1997. The Cracidae: their biology and versity of Glasgow, Glasgow. conservation. Hancock House, Surrey, British BEGAZO, A. J., AND R. E. BODMER. 1998. Use and Columbia. conservation of Cracidae (Aves: Gallifonnes) STRAHL, S.D., AND A. SCHMITZ. 1997. A taxonomic in the Peruvian Amazon. Oryx 32:301-309. reference of the family Cracidae for common BROOKS, D. M. 1999. Pipile as a protein source to use by ornithologists. Pp. 1-7 and 503-506 in rural hunters and Amerindians. Pp. 42-50 in The Cracidae: their biology and conservation Biology and conservation of the Pipi11g Guans (S.D. Strahl, S. Beaujon, D. M. Brooks, A. J. (Aves: Cracidae) (D. M. Brooks, F. Olmos, and Begazo, G. Sedaghatkish, and F. Olmos (eds). A. J. Begazo, eds). Spec. Pub!. Cracid Spec. Hancock House, Surrey, British Columbia. Group, No. 1. TEMPLE, S. A. 1999. The status of Pipile pipile in COLLAR, N.J., L. GONZAGA, N. KRABBE, A. MAD­ Trinidad. P.13 in Biology and conservation of RONO NIETO, L. NARANJO, T. A. PARKER Ill, the Piping Guans (Aves: Cracidae) (D. M. AND D. WEGE. 1992. 1l1reatened birds of the Brooks, F. Olmos, and A. J. Begazo, eds). Spec. Americas. The ICBP/IUCN Red Data Book. Pub!. Cracid Spec. Group, No. 1. Smithsonian Institutition Press, Washington, V AURIE, C. 1967. Systematic notes on the bird fam­ DC. 1150 pp. ily Cracidae. No 7. The genus Pipile. Amer. DELAC~OUR, J., AND D. AMADON. 1973. Curassows Mus. Novit. 2296:1-16. and related birds. American Museum of Nat­ V AURIE, C. 1968. Taxonomy of the Cracidae. BulL ural History, New York. 247 pp. Amer. Mus. Nat. Hist. 138:131-260. Esn.rDILLO-LOPEZ, J. 1979. The Cracidae. Avicult. ZE:-

Two residents of Matelot reported that they still 295 and 460 m. Primary montane forest covers the regularly saw Pawi in the forest to the west of the hills and much of the valley floor, while secondary village. forest and semi-abandoned coffee and banana Cumana, Northeast Coast. -Reports given to plantations are locally frequent on the valley floor. the Forestry Division (C. James pers. comm.) sug­ In this area (3 July) we observed a Pawi for nearly gested that Pawi fed very close to an estate house an hour in vine forest on steep ground on the north in this locality. We visited the occupants of the side of the valley, sitting in and occasionally pluck­ house, who informed us that Pawi had not been ing at the leaves of an 'ironwood' tree (unidenti­ seen there for at least 2 mo and that they had fied) from 1150-141 0). The occupants of the estate probably been shot by hunters. We therefore did house told us that Pawi regularly come down to the not survey this site. coffee plantations and, in the evening, sit in trees Cumaca, upper Oropuche River Valley. -Four close to the house. Our second daytime trip yielded trips were made to this site (3, 8 and 30 July and 3 no observations and on two overnight camping August) at 115-130 m elevation. Steep ridges sur­ trips we did not see or hear any Pawi. rounding the valley at this point rise to between

Trinidad Piping-Guan (Pipile pipile). Illustration by Edward Rooks. Pp. 131 -137 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci. , Univ. West Indies, St. Augustine, Occ. Pap. I I, 2002.

LONG-TERM PERSISTENCE OF WHITE-BEARDED MANAKIN (MANACUS MANACUS) LEKS IN THE ARIMA VALLEY OF TRINIDAD, WEST INDIES

MARK E. BERRES Zoological Museum and Department ofZoology, University of Wisconsin, 250 North Mills Street, Madison, WI 53 706-1313, USA

ABSTRACT.-Dming 1997-2000, I searched for 11 White-bearded Manakin (Manacus manacus) leks studied by Snow (1958-1961) and Lill (1967-1971) in the lower Arima Valley of Trinidad. Four of the leks described by Snow and one by Lill were found in precisely the locations indicated by these authors 29-42 yr ago. Actively displaying males and visiting females attended each of these leks. However, two leks appear affected by a dissolution process. Oftl1e six leks not found, habitat alteration by humans appeared responsible for the abandonment of three; the factors responsible for the demise of the remaining leks remain unknown. All smviving leks occur in areas distant from human activities, suggesting that leks will persist indefinitely in the absence of any significant disturbance.

RESUMEN.-Durante 1997-2000, se buscaron 11 leks del Saltarin Maraquero (Manacus manacus) estudiados por S11ow (1958-1961) y Lill (1967-1971) en el Valle del bajoArima en Trinidad. Se encontraron cuatro de los leks descritos por Snow y uno por Lill ubicados precisamente en las localidades indicadas por los autores hace 29-42 afi.os. Cada lek fue asistido por machos desplegando activamente y hembras visitantes. Sin embargo, dos de los leks parece que fueron afectados por un proceso de disoluci6n. De los seis leks no encontrados, Ia alteraci6n del habitat pareci6 ser responsable por el abandono de tres; los factores responsables para el fallecimiento de los otros leks son desconocidos. Los leks que sobrevivieron se encuentran en zonas distantes de las actividades lmmanas y esto sugiere que los leks persistiran indefinidamente en Ia ausencia de a]g{m disturbio significative.

KEY WORDS.-lek dissolution, lek persistence, Manacus manacus, Pipridae, population structure, Trinidad, W11ite-bearded Manakin

Within the class Aves, at least 97 species ex­ Manakin (Manacus manacus) is undoubtedly a hibit lek-based mating systems (Hoglund and lekking passerine (Snow 1962a, Lill 1974a, b) even Alatalo 1995). Of these, the majority are distributed by the stringent definition of a lek proposed by within five families: Phasianidae (grouses of Tetra­ Bradbury (1981 ). The White-bearded Manakin is a ominae), Trochilidae (hummingbirds), Cotingidae common, widely distributed forest-interior bird (cotingas), Paradisaedidae (birds of paradise) and resident in Trinidad and throughout much of Pipridae (mana.k.ins). However difficult it may be to mainland South America (Ridgely and Tudor 1994). define a lek (Bleiweiss 1997), the White-bearded Especially noted for elaborate courtship rituals,

131 132 BERRES

White-bearded Manaklns perform spectacularly returning to the site where Chapman (1935) con­ choreographed aerial and mechanically-produced ducted his research on the Golden-collared Mana­ auditory displays. At the lek, resident males clear kin (Manacus vitellinus) 26 yr earlier. The Iek was leaf litter and other debris from small areas on the still active in the same locality described by Chap­ forest floor, creating individual courts from which man. their stereotyped displays are perfotmed (Snow Studies published by David Snow (1962a) and 1962a). Although males attend the lek throughout Alan Lill (1974a, b) on the life histories of White­ the year, peak visitation and display activity occur bearded Manakins in Trinidad provide an un­ during the rainy season (Snow 1962a), the onset of precedented oppmtunity to assess lek persistence, which is variable but usually occurs in May or June which is the objective ofthis paper. My motivation (Beebe 1952). Lek attendance and display intensity for this aualysis arose from the hypothesis that the are reduced markedly during moult, which occurs degree of lek persistence would affect the genetic from August through December (Snow l962a). composition of natural populations exhibiting a lek­ Studies oflekking birds usually report that leks based mating system. Also, a temporal context in recur at identical or nearly identical locations from which to interpret genetic patterns will enhance my year to year. However, most such studies are short­ ongoing studies of the genetic population structure term and involve temperate-zone species. For of White-bearded Manakins in Trinidad and Brazil. example, Patterson (1952) recorded the locations of Sage Grouse (Centrocercus urophasianus) leks in METHODS Wyoming (USA) for 3 yr. Twenty-eight leks in a 526 km2 area were counted during the first year. In From June 1958 to September 1961, Snow the following 2 yr, all leks attended in previous (l962a) studied White-bearded Manakins in the years were occupied despite an estimated 26% de­ lower Arima ValleyofTrinidad. From 1967-197l,Llll cline in Sage Grouse population density. Another (J 974a, b) studied some of the same leks described 3-yr study of twenty Sharp-tailed Grouse (Tym­ by Snow (l962a). During the summerof1997, I used panuchus phasianellus) leks in Canada also re­ hand-drawn maps published in Snow (1962a, Fig. 3) ported invariant lek attendance in successive years and Lill ( 1974a, Fig. 1) to retrace the authors' routes (Rippin and Boag 1974). However, no tall short-term in their study area of approximately 182 ha. I studies reveal this high degree of lek locality searched for White-bearded Manakin leks more persistence. A study by Gratson (1988) on Shatp­ exhaustively during the summer of 1998 and to a tailed Grouse in Wisconsin (USA) showed that lesser extent in January 1999 and the summers of only 56% of leks (n = 25) remained active at the 1999 and 2000, gtid-searching the study area same site during 3 yr. Furthermore, in North Dako­ primarily during peak hours of male display activity ta (USA), only 41% of Sharp-tailed Grouse leks (n (early morning and early afternoon). The abun­ = 178) remained active more than 5 yr (Bergerud dance of resident male White-bearded Manaklns at and Gratson 1988). each lek was estimated by averaging (during at Studies of lek persistence and attendance over least 11 visits) the number of males occupying longer time periods remain rare, partly because courts on the lek. Additionally, the number of long-term observations preclude expedient data courts and relative spatial position of each court collection and publication. However, published was recorded. accounts oflekking birds can provide historical lek locality information if the author(s) described the RESULTS geographical location of the lek precisely enough to allow for subsequent follow-up visits. Although Although crudely hand-drawn, the maps of information concerning the lek during the interim both Snow (1962a) and Lill (1974a) provided suf­ may be unavailable, the cuJTent status of the lek ficient detail for me to search for the origiual 11 can be ascertained. For example, in 1958, Snow White-bearded Manakin leks. I located five (45%) (1962a) visited Barro Colorado Island in Panama, of these leks, including four (leks A, C, D and H) of Lek Persistence in the White-bearded Manakin 133

61° 18'W 61° 17'W

FIG. I. Contour map of the study area in the lower Arima Valley, Trinidad. Boxed letters indicate White­ bearded Mm1akin (Manacus manacus) leks described by Snow (1962a). Circled letters indicate leks discovered later by Lill (1974b). Elevations are in ft; contour intervals are 50 ft. Dashed lines indicate streams; the heavy black line is the Arima-Blanchisseuse Road. The triangle indicates the location of a concrete bridge that crosses the Arima River approximately 4 km north of the borough of Arirna. This reference position delimits the traditionally recognized southern entry point into the Northern Range. Grid lines are referenced to map Sheet 14, Lands and Surveys Division, P01t of Spain, Trinidad. 134 BERRES

TABLE I. Court abundance and resident male abun­ lek A (Fig. I, Table 1), each occupied by a single dance for each surviving lek. adult male, which I captured and colour-banded. Females visited this small lek noticeably less than Court Resident male otherlarger leks in the area. During two full days of Lek abundance abundance observation at lek A, I observed only three female A 5 5 visits; although typical male displays ensued, I did c 27 20 not witness any copulation attempts. However, I D 21 18 observed each resident male at lek A visit the much H 36 32 larger lek C (Fig. 1, Table I) on multiple occasions K 20 17 even though these males did not appear to defend courts at lek C. I never observed males resident at lek C visit lek A. eight in the locations described by Snow (1962a) and one (lek K) of three aditional leks reported by DISCUSSION Lill (1974a) in the study area (Fig. 1). The precise localities of leks A, C, D, H and K were confirmed My study clearly indicates that nearly half of by local residents who assisted Snow (Jogie Ram­ the White-bearded Manakin leks are still active at lal) and Li11 (Poren Ramdass) during their studies in their original locations. However, the factors medi­ Trinidad. No additional leks were located in the ating this impressive persistence remain uncertain. study area. Four of these leks (A, C, D and H) were Bradbury et al. (1989) asserted that a prerequisite at least 42 yr old and one (K) was at least 29 yr old. for lek persistence is a stable habitat which neces­ Estimates of court abundance and resident male sarily includes spatially persistent resources such abundance for each lek ranged from 5-36 and 5-32, as food and breeding sites. If so, it is reasonable to respectively (Table I). predict that in the absence of major environmental The habitats immediately surrounding three of disturbances, a lek should remain at a single lo­ the six dissolved White-bearded Manakin leks (B, cality indefinitely. F and I; Fig. I) had been significantly altered by The dissolution of three leks attributable to construction and clearings for power-lines or agri­ human disturbance suggests that major disturban­ culture. In contrast, the other three dissolved leks ces may play a significant role in lek dissolution, at (E, G and J) appeared to be in undisturbed forest, least for White-bearded Manakins. W11ether or not although lek J was separated from a logged and lek H will be adversely affected in the long te1m by cultivated area by only a 1idge and streambed. the disturbance observed in 1997 remains uncer­ Three of the four leks known to have persisted tain. Both males and females may have been absent the longest (leks A, C and D) were the most distant from lek H during January 1999 because January is from human activities and in undisturbed habitat. outside the typical breeding period of White-beard­ However, the area surrounding lek H was selective­ ed Manakins in Trinidad, which extends from ly logged during early 1997. Although not com­ March through August (Snow 1962a). Tn addition, pletely cleared, the habitat disturbauce destroyed important fruiting resources (Melastomaceae and many individual courts. Surprisingly, compared to Rubiaceae) were lacking at known feeding sites in the other remaining leks, both male and female at­ the area. Fruiting trees were observed at other leks teudance was greatest at this lek during the summer in the study area, all of which were active at the months of 1997 and 1998. In early January 1999, I time. observed only three of 32 colour-banded males White-bearded Manakin leks may dissolve for !mown previously to defend courts on lek H. Nev­ other reasons. Resident male W11ite-bearded Mana­ ertheless, I counted 36 courts, all ofwl1ich I deemed kins require at least two saplings at the court for active due to their tidy appearances. displays such as the 'snap-jump', 'grunt-jump' and Lek A appeared to be in a late stage of dis­ 'slide-down-the-pole' (Snow 1962a). An estab­ solution. In 1997 and 1998, I observed five courts at lished lek would thus require a significant number Lek Persistence in the White-bearded Manakin 135 of such saplings. Although saplings may persist jacent leks, which may have been occurring at lek for years, they eventually mature or die, thus de­ A. Lill (J974a) reported twenty dominant males pleting an obligatory resource. Therefore, the lek present at lek C. Although estimates of resident might shift to a different area containing suitable male abundance were not provided, Snow (1962a) numbers of saplings in addition to other necessary observed 24-28 courts present at Iek A during 4 yrs resources. However, this scenario does not appear (although the observed number of courts on a lek applicable to leks A, C, D, H and K, which still provides a good estimate of resident male abun­ persist. Perhaps the age distribution of the sap­ dance, the presence of 'practice courts' [Snow lings at these leks is stable although no data are 1962a] precludes equating directly the two quan­ available to support this hypothesis. tities). Snow (1962a) also reported that a single The longevity of White-bearded Manakins adult male, unsuccessfully established at lek A, may also promote long-term lek persistence. White­ moved to lek C where he eventually acquired a bearded Manakins are among the longest-lived court. passerine species (Snow and Lill 1974). Li11 's When a lek dissolves, the resident males and (1974b) observations of eleven resident male visiting females probably do not perish, but rather White-bearded Manakins, originally banded by search for another active lek. Reduced male density Snow (1962a), indicated an average age of at least or significantly reduced female visitation at a lek 9 yr. One actively breeding male was known to be may stimulate resident dominant males to search for at least 14 yr old. Such rarely demonstrated male other leks. Subordinate male White-bearded Mana­ longevity might confer substantial effects on lek kins and Golden-headed Manakins apparently stability, especially u11der a hotshot evolutionary travel from lek to lek attempting to establish resi­ model (Arak 1982; Beehler and Foster 1988), by dency (Snow 1962a, b, Lill 1974a, b, 1976). My minimizing resident male turnover. Indeed, Lill observations of the five resident males at lek A (1974a) recorded low annual tumover (18.2% and visiting the much larger lek C may represent such a 11.1% over a 2-yr period) of resident male White­ scouting process. Nevertheless, the fidelity of bearded Manakins. males to their primary leks is strong as evidenced The dissolution of existing leks and the by the long-term persistence of lek A. emergence of new ones may also correlate directly In birds, increased average per capita mating with increases and decreases in population density, success on larger leks (Alatalo et al. I 991, Hoglund as conjectured by Dalke et al. (1963) for Sage et al. 1993) may be a p1ausible mechanism for lek Grouse. However, Braun and Beck (1985) found growth and could also account for the expansion of that harvesting yearling Sage Grouse males at an one lek at the expense of another. Under this model, annual rate of 10.9% to recreational hunting (n = 10 it is feasible that individuals from the smaller leks A yrs) caused no measurable perturbation of their and G may have migrated to the closely adjacent populations. Yet, numbers of males at actively leks C and H, respectively. However, a similar situ­ attended leks ranged from a low of 17 to a high of ation exists between leks D and K, both of which 35 during the study period. There is little evidence have approximately the same number of courts and to suggest that population densities of tropical resident males (Fig. 1, Table 1) . lekking species change significantly over short time Clearly the processes mediating lek persistence periods, which may explain why leks appear stable. are complicated and poorly understood. Designing Additional examples of apparently stable tropical experiments that address the affects of factors such avian leks include those of Golden-headed Ma­ as habitat and resource stability, population age nakins (Pipra e1ythrocephala; Lill 1976), Green structure and disturbance will remain challenging. Hermits (PhaethornL~ guy; Snow 1974) and Long­ tailed Hermits (Phaethornis superciliosus; Stiles ACKNOWLEDGEMENTS and Wolf 1979). A possible effect of decreased population I am indebted to many individuals and or­ density is the movement of resident males to ad- ganizations for assisting my research in Trinidad. 136 BERRES

First, I especially thank my spouse, Ann M. chromatism and plumage colours in lekking MacLaughlin-Berres, for her help with field work. and non-lekking birds: a comparative analysis. Second, I thank N. Nathai-Gyan, D. Chadee and the Evol. Ecol. 11:217-235. office staff at the Wildlife Section of the Forestry BRADBURY, J. W. 1981. The evolution of leks. Pp. Division, Trinidad, for their friendliness and effi­ 138-169 in Natural selection and social be­ ciencyin issuing permits. R. Quamina and I. Lambie havior: recent research and new theory (Alex­ of the Asa Wright Nature Centre allowed me to ander, R. D. and D. W. Tinkle, eds.). Chiron stay at the William Beebe Research Station, where Press, New York. R. and L. Hernandez were always a source of pleas­ BRADBURY, J. W., S. L. VEHRENCAMP, AND R. M. urable conversation. J thank J. Ramlal for permis­ GIBSON. 1989. Dispersion of displaying Sage sion to conduct research on his property and for Grouse. I. Patterns of temporal variation. discussim1s concerning historical aspects of mana­ Behav. Ecol. Sociobiol. 24: 1-14. kin studies in the Arima Valley. C. Collins, M. BRAUN, C. E., AND T. D. I. BECK. 1985. Effects of Foster, J. Kirsch, R. Prum and D. Snow provided changes in hunting regulations on Sage insightful comments on earlier drafts ofthis paper. Grouse harvest and populations. Pp. 335-343 T especially tl1ank F. and M. Hayes for their gen­ in Game harvest management. Proceedings of erosityin helping me initiate and continue fieldwork the third intemationl symposium (S. L. Beasom in Trinidad and Tobago. Funding for this project and S. F. Robertson, eds.). Caesar Kleberg was pro-vided in part by the Natural History Mu­ Research Institute, Kingsville, TX. seums Council, the Zoological Museum and the CHAPMAN, F. M. 1935. The courtship of Gould's Department of Zoology, all of the University of Manakin (Manacus vitellinus vitellinus) on Wiscon-sin, Madison; and the Frank M. Chapman Barro Colorado Is land, Canal Zone. Bull. A mer. Memorial Fund of the Ametican Museum ofNatural Mus. Nat. Hist. 68:471-525. History. DAKLE, P. D., D. B. PYRAH, D. C. STANTON, J. C. CRAWFORD, AND E. SCHLAITERER. 1963. Ecol­ LITERATURE CITED ogy, productivity, and management of Sage Grouse in Idaho. J. Wild!. Manage. 27:810-841. ALATALO, R. V., J. HOGLUND, AND A. LUNDBERG. GRATSON, M. W. 1988. Spatial patterns, move­ 1991. Lekking in black grouse-a test of male ments, and cover selection by Sharp-ta1led viability. Nature 352:155-156. Grouse. Pp. 158-192 in Adaptive strategies and ARA.K, A. 1984. Sneaky breeders. Pp. 154-194 in population ecology of northern grouse, vol. I Producers and scroungers: strategies of exploi­ (A. T. Bergerud and M. W. Gratson, eds.). tation and parasitism (C. J. Barnard, ed.). University of Minnesota Press, Minneapolis, Croom Helm, London. MN. BEEBE, W. 1952. Introduction to the ecology of the HOGLUND, J., AND R. V. ALATALO. 1995. Leks. Arima Valley, Trinidad, B.W.I. Zoologica 37: Princeton University Press, Princeton, NJ. 248 157-184. pp. BEEHLER, B. M., f~"'D M.S. FOSTER. 1988. Hotshots, HOGLUND, J., R. MONTGOMERIE, AND F. WIDEMO. hotspots and female preferences in the organ­ 1993. Costs and consequences of variation in ization of lek mating systems. Amer. Nat. 131: the size of Ruff leks. Behav. Ecol. Sociobiol. 203-219. 32:31-39. BERGERUD, A. T., AND M. W. GRATSON. 1988. LJLL, A. 1974a. Sexual behavior of the lek-forrning Survival and breeding strategies of grouse. Pp. White-bearded Manakin (Manacus manacus 473-577 in Adaptive strategies and population trinitatis Hartert). z. Tierpsychol. 36:1-36. ecology of northern grouse, vol. 2 (A. T. Llll, A. 1974b. Social organization and space Bergerud and M. W. Gratson, eds.). University utilization in the lek-forrning White-bearded of Minnesota Press, Minneapolis, MN. Manakin, M manacus trinitatis Hartert. Z. BLEIWEISS, R. E. 1997. Covariation of sexual di- Tierpsychol. 36:513-530. Lek Persistence in th e White-bearded Manakin 137

LILL, A. 1976. Lek behavior of the Golden-headed Ibis 116:278-297. Manakin, Pipra erythrocephala, in Trinidad SNOW, D. I 962a. A field study of the Black and (Westlndies). Adv. Ethol. 18:1-83 . White Manakin, Manacus manacus, in Trin­ PATIERSON , R. L. 1952. TI1e Sage Grouse in Wyo­ idad. Zoologica47:65-104. ming. Sage Books, Denver, CO. SNOW, D. 1962b. A field study of the Golden­ RIDGELY, R. S., AND G. TuDOR . 1994. The birds of headed Manakin, Pipra erythrocephala, in South America. Vol. II. The suboscine pas­ Trinidad, W. T. Zoologica 47 :183-198. serines. University of Texas Press, Austin, TX. SNOW, D., AND A. L!LL. 1974. Longevity records for 814 pp. some Neotropical land birds. Condor 76:262- RIPPIN, A. B., AND D.A. BOAG. 1974. Recruitment to 267. populations of male Sharp-tailed Grouse. J. STILES, F. G., AND L. L. WOLF. 1979. Ecology and Wild!. Manage. 38:616-621. evolution of lek mating behavior in the Long­ SNOW, B. K. 1974. Lek behaviour and breeding of tailed Hermit hummingbird. Omithol. Monogr. Guy's Hermit hummingbird Phaethornis guy. 27:1-87. Pp. 138-143 in Studies in Trinidad and Tobago Omithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. II, 2002.

NOTES ON THE BIOLOGY OF THE BAND-RUMPED SWIFT IN TRINIDAD

CHARLES T. COLLINS Department ofBiological Sciences, California State University, Long Beach, CA 90840, USA

ABSTRACT.-The Band-rumped Swift (Chaetura spinicauda) in Trinidad has a breeding and moult cycle coinciding with the dry season flowering period. This differs from the early rainy season breeding period of other swift species and can represent a type of seasonal resource partitioning. Breeding may be biannual.

RESUMEN.-El Vencejo Lomiblanco (Chaetura spinicauda) en Trinidad tiene un periodo de nidificaci6n y muda que coincide con el periodo de floraci6n de Ia estaci6n seca. Este difiere de las otras especies de vencejos las cuales anidan a comienzo de Ia estaci6n lluviosa y puede representar un tipo de repartici6n estacional de recursos. La nidificaci6n puede ser bianual.

KEYWORDS.-Apodidae, Band-rumped Swift, Chaetura spinicauda, Trinidad, body mass, moult, biannual breeding season

As pointed out by Snow ( 1962: 129), "Trinidad zuela (Delta Amacuro, Paria) and west through is especially suitable for field studies of swifts. southern Venezuela (Bolivar, Amazonas; Meyer de Here, on an island measuring some 50x30 miles Schauensee and Phelps 1978) to eastern Colombia [80x48 km] , seven species are resident five of them (Caqueta, Putumayo; Hilty and Brown 1986). It also are known to breed and all probably do so." In­ occurs on the Pacific slope west of the Andes in cluded in this abundance of swifts are four mem­ Colombia (south to Valle; Hilty and Brown 1986) bers of the genus Chaetura. Field studies between and Ecuador (Guayaquil, Esmeraldas, Pichincha; 1957 and 1972 provided substantial information on Marin et al. 1992), across the northern lowlands of the Short-tailed Swift (Chaetura brachyura), Gray­ Colombia to Santa Marta and Guajira (Hilty and romped Swift (Chaetura cinereiventris), and Chap­ Brown 1986), and north through much of Panama to man's Swift (Chaetura chapmani; Snow 1962, the southern Pacific slope of Costa Rica (Wetmore Collins 1968a, 1968b). Despite being commonly 1968, Stiles and Skutch 1989). In northern Vene­ observed, less complete data were obtained for the zuela, it is surprisingly absent from the Cordillera de Band-rumped Swift (Chaeiura spinicauda; Snow Ia Costa Central and from most of the Cordillera de 1962, ffrench 1991, Collins unpubl. data). Since no Ia Costa Oriental except for the foothills of the Pari a further information on this swift in Trinidad has Peninsula (Meyer de Schauensee and Phelps 1978). been presented in the nearly three ensuing dec­ A review of this species' distribution, subspecies ades, it seems appropriate to summarise what little limits and superspecies affinities is presented by is known and suggest directions for further re­ Marin (2000) search. The population inhabiting Trinidad is attribut­ The Band-rumped Swift occurs from northern ed to C. s. spinicauda, which also occurs through­ Amazonian Brazil (Amazonas, Para; Sick 1993) out the Guianas and northeastern Brazil. Band­ north through the Guianas to northeastern Vene- rumped Swifts are usually described as occurring

138 Biology of Band-rumped Swifts 139 over low to mid-elevation forests or in openings in Chaetura spinicauda fromBelem, Para, Brazil, were the forest at elevations generally below 1500 m examined (LACM 42363-42373). (Hilty and Brown 1986, Stiles and Skutch 1989, Marin 1993). The only reported natural nest site RESULTS was located about 30 ft (9.2 m) up in the hollow trunk of a Chataigne tree (Pachira insignis) in Foraging behaviour.-Although Band-rumped Arima Va11ey, Trinidad, in July 1959 (Snow 1962). Swifts were mist-netted higher in the Northern Band-rumped Swifts have on occasion been noted Range and found roosting in the savanna region, roosting with post-breeding flocks of Short-tailed they were most commonly observed in the middle Swifts in subterranean man-holes on Waller Field elevations in Arima Val1ey. They were regularly (Snow 1962, Collins unpubl. data). observed in mixed-species feeding flocks, most frequently associated with Gray-rumped Swifts that METHODS tended to occur from middle to higher elevations in the Northern Range. Band-rumped Swifts were dis­ My observations of Band-rumped Swifts were tinctly less commonly observed in the lowland sa­ made in Trinidad during 3-6 mo offield work in each vanna areas, such as Waller Field, in association of the years 1961-1964 and during shorter periods with Short-tailed Swifts. All four species of Chae­ of up to 3 wk in 1966, 1967, 1968 and 1972. During tura swifts were observed to forage above the this time I was able to gain an overall impression of forest canopy up to approximately l 00 m above Band-rumped Swift distribution and foraging be­ ground level. They also passed low ( < 2 m) over the haviour. Quantified data on body mass and moult ground when crossing an open ridge and occasion­ were obtained from birds mist-netted while flying ally foraged low over the ground to exploit local­ low over a ridge at the head of Arima Valley in the ised or temporary insect abundances. However, center of the Northem Range. Body mass was Band-rumped Swifts were distinctly more frequent­ measured to the nearest 0.25 g using a Pesola ly observed foraging near the forest canopy or be­ spring balance calibrated to 0.5 g increments. low canopy level in openings in the forest and I collected 32 specimens of Band-rumped along road cuts. Single individuals or small groups Swifts at one location: St. George Co., 11.5 miles of swifts foraging in these situations were nearly (I 8.5 km) north of A rima on the Arima-Blanchis­ always identified as Band-rumped Swifts and not seuse Road at an elevation of 1800 ft (549 m). These other Chaetura species. Other observers similarly specimens are housed in the collections of the have noted Band-rumped Swifts using semi-open American Museum of Natural History (AMNH) in areas, pastures and agricultural areas (Hilty and New York, the University of Michigan Museum of Brown 1986, Stiles and Skutch 1989, Marin et al. Zoology (UMMZ) in Ann Arbor, Ml, the Natural 1992). The extreme mobility of these swifts, which History Museum of Los Angeles County (LACM) rapidly move up and down valleys and across in Los Angeles, the Western Foundation for Verte­ watersheds (Snow 1962), easily defeated any brate Zoology (WFVZ) in Camarillo, CA, and Cal­ scheme I envisioned to quantify possible inter­ ifornia State University (CSULB) in Long Beach, specific differences in foraging behaviour. CA. [n addition to study skins, six specimens were Body mass.-The Band-rumped Swift is one of prepared as skeletons (sk) and three as anatomical the smaller Chaetura swifts. The body mass of 45 specimens (a). Additional swifts were netted and birds captured throughout most of the year ranged released at the same location by D. W. S11ow, R. from 13.0 g to 17.5 g and averaged 15 .3 g (Table 1). and M. ffrench and myself. Specimens examined: Included were weights of 19 males and ten females; AMNH 786220-786225, 786046, 788352-788356, each sex averaged 15.3 g. There was no significant 793121-793122, 67537-6538 (sk), 6595 (sk), uncat­ seasonal difference in body mass (ANOV A, P = alogued4 (a), UMMZ210808 (sk), LACM 83566to 0.75) as noted elsewhere for migrant species 83568, WFVZ49046-49047, CSULB 5382 (sk), CTC (Collins and Bull 1996). This supports the inference uncatalogued 4. An additional 11 specimens of that Band-rumped Swifts are permanent residents in 140 COLLINS

TABLE I. Seasonal vatiation in body mass (g) of TABLE 2. Body mass (g) of Band-rumped Swifts in Band-rumped Swifts in Trinidad. Trinidad.

Month Mean SD Range n Mean SD Range n January 15.10 0.87 13.75-16.5 7 14 .20 13.0-18.0 21 a February 15.20 13.0-20.0 68b March 15.15 0.43 14 .5-15.75 5 15.33 l.OO 13.0-17.5 45" April 16.05 0.81 15.0-17.5 5 "Snow 1962, Snow and Snow 1963a May 15.25 0.96 14 .0-16.75 10 bffrench 1991 June 15 .25 0.00 15.25-15.25 2 "this study July 16.50 0.75 15 .75-17.25 2 August September consistent with an April starting date. All but one ofthe 43 other Band-rumped Swifts captured in this October 15.21 1.16 13.0-17.0 13 study between 31 July and 18 March showed no November 14.50 - 14.5 signs of primary moult. The one exception was a December single swift (AMNH 786220) captured on 29 Oc­ tober 1966 with Pl 0 (outermost) two-thirds re­ placed. None of the seven other Band-rumped Trinidad. The mean body mass recorded here is Swifts caught on this late date showed any signs of similar to data presented by Snow (1962) and primary moult, suggesting that moult was atypical ffrench (1991) obtained from swifts mist-netted at at this time of the year. Two other Band-rumped the same site in the Northern Range in other years Swifts completing primary moult on 3 August and (Table 2). The maximum body mass they recorded, 23 October were reported by Snow (1962). Four 18.0 g (Snow 1962) and 20.0 g (ffrench 1991), ex­ fresh-plumaged swifts with a distinct greenish ceeded the maximum mass of 17.5 g that I recorded. gloss caught and released on 3 May 1967 may have The minimum body mass, 13.0 g, was the same in aU been recently fledged young. Swifts handled in three data sets. January and March appeared distinctly worn, as in Moult.-Chaetura swifts typically have a sin­ other Chaetura swifts just prior to the start of the gle complete annual moult that begins with the in­ annual moult (Co11ins 1968a). These data suggest nermost primaries and progresses outward with the annual flight feather moult in Band-rumped only one or two feathers growing simultaneously Swifts begins in April and is completed by late July (Collins 1968b). Moult of the secondaries and or early August. Body moult was less predictable rectrices generally begins after primaries 3-4 (P3-P4, and noted in individuals as early as I 8 March 1972 numbered from innermost) have been replaced and and as late as I 3 October 1964. finishes prior to the replacement of the outermost Elsewhere in its range, four specimens of primaries. Body moult is also generally included in Band-rumped Swifts from Bel em, Para, Brazil, were the period required for moult of all of the primaries moulting P9 or PI 0 between 5 and 12 July (LACM (Collius 1968b, unpubl. data). Only three of the 42364,42366,42369, 42370) and five specimens were Band-rumped Swifts I captured were in active pri­ in entirely fresh plumage (LACM 42363, 42365, mary moult. One individual (AMNH 788353) netted 42367, 42368, 42371) at this same time. On 12 May, on 20 April 1967 had replaced P l; P2 was half re­ one specimen (LACM 43272) had P6 half regrown grown. This suggests an early to mid-April start of and a second (LACM 42373) was in fresh plumage. the annual primary moult. A second individual At Belem, the rainy season starts in December and (AMNH 3536) caught on 7 June 1964 had P4 two­ the dry season begins in May or June (Snow and thirds regrown and P5 was an entirely ensheathed Snow 1964). pin feather; P1-P3 were newly regrown. This is also Breeding.-No direct evidence of breeding was Biology of Band-rumped Swifts 141 obtained in this study. However, data on gonad and November indicates a possible second period size was recorded from 30 specimens collected be­ of breeding. Although it also possible that these tween June 1964 and March 1972. Four of five late breeding swifts were migrants from some main­ males collected on 15 and 18 January 1968 were re­ land population, I did not record any difference in corded as having testes slightly enlarged (2-5 mm appearance or seasonal change in body mass long) as did one male collected on 18 March 1972. which might support this idea. Two breeding sea­ Two other males collected on 23 March has testes sons per year has been recorded for the Little Swift partially enlarged (8.5-9 mm long) and three males (Apus affinis) in India (Naik and Razack 1967) and collected on April 20, 1967 had testes greatly en­ the Scarce Swift (Schoutedenapus myoptilus) in larged (11-12 mm long). The two females collected Africa (Prigogine 1966). Biannual breeding has not on this date showed enlarged ovaries (3 x6, 3x7 previously been reported for any Neotropical swift mm). A second period of gonad enlargement was and requires additional confirmation for Band­ noted in October 1966 when males with partially to rumped Swifts in Trinidad. fully enlarged testes (5-1 0 mm) were recorded on 23 The climate of the Arima Val ley is moist tropi­ October (one) and 29 October (three of four); only cal, with seasonal forest at the nearly sea-level low­ one of three females collected on these dates er portion and lower montane rain forest near the showed partial enlargement of the ovary. 1800 ft (549 m) upper end (Beebe 1952). In the valley, as in Trinidad as a whole, there are two dis­ DISCUSSION tinct seasons. A long dry season typically begins in late December and ends in May. A single wet The pattern and duration of the annual com­ season lasts the rest of the year but is often broken plete moult of Band-rumped Swifts in Trinidad by a short dry season, or petit careme, in Septem­ seems similar to that recorded for other Chaetura ber or October(Beebe 1952, Snow and Snow 1964). swifts. Moult in Short-tailed Swifts takes about 4 Annual rainfall in Arima Valley averaged 108.1 in mos beginning in late July or early August and (2746 mm; Beebe 1952). Blooming activity is intense ending by late November (Snow and Snow 1964, during the dry season, particularly when many Collins 1968b, Col !illS unpubl. data). Similarly, Gray­ deciduous trees drop their leaves and flower rumpedSwifts weremoultingP1-P3 on 31 July 1964 (Beebe 1952, Snow and Snow 1964). and P7-P10 on 13 October 1964 (Collins unpubl. Previous studies have shown that many Trini­ data). The striking difference in the moult of Band­ dad birds have geared their reproductive cycles to mmped Swifts is that it begins in April and ends by that time of the year when the maximum food abun­ late July or early August, which is about 4 mos dance is available for egg formation and chick rear­ earlier than the starting and ending dates for three ing (Snow and Snow 1963b, 1964). In the case of other Chaetura swifts in Trinidad. the swifts and swallows, except the Band-rumped The breeding cycle for the Short-tailed Swift in Swift, this period occurs in the early part of the Trinidad is well documented (Snow 1962, Collins rainy season when aerial insects appear to be most 1968b). In this species eggs were laid from April to abundant (Snow 1962, Snow and Snow 1964, Col­ August or September. The period of moult over­ lins 1968b ). lapped with the period of chick rearing (Snow Hummingbirds, which depend on flowers for 1963a, Collins 1968b). By extrapolation, the period both nectar and their associated insects, breed of egg laying and chick rearing in Band-rumped largely during the December to April dry season Swifts should largely precede the period of moult when many trees with large and conspicuous blos­ and probably occurs from late January to early soms particularly attractive to hummingbirds come April. Late nests or second broods could occur into flower (Snow and Snow 1964). In Trinidad, much later and would explain the single obser­ Band-rumped Swifts regularly forage closer to the vation of adults apparently feeding young on 24 canopy, or even below canopy level, than other July (Snow 1962). The presence of enlarged go­ Chaetura swifts (pers. obs.). In Ecuador, Band­ nads in Trinidad Band-rumped Swifts in October rumped Swifts are among those swifts that forage 142 COLLINS nearer to the ground than other swift species and young could also be analysed and might show a lower than Gray-mmped Swifts when in mixed high incidence of flower pollinating insects in their species feeding flocks (Marin 1993). Many swifts diets. If so, this would support the ideas presented have been observed to fly up close to foliage to here relating low level foraging and flowering glean insects (Stiles and Skutch 1989, Col1ins, season breeding in Band-rumped Swifts in Trin­ unpublished). It is possible that the low-flying idad. Band-rumped Swifts do this more commonly than In conclusion, Band-rumped Swifts show some the other higher flying swifts, but additional quanti­ distinct differences from other Trinidad swifts in fication is required. their breeding phenology. Further monitoring of The period ofmaximum resources for such low­ their annual cycle should strengthen some of the flying swifts may be during the dry season when suggestions made here and certainly add to our flowers and their associated insect pollinators are knowledge of this enigmatic swift. abundant. Thus the earlier dry season breeding a11d moult cycle of this swift can be considered as an ACKNOWLEDGEMENTS adaptive shift in timing, also found in humming­ birds, coinciding with the seasonal abundance of Support for field work in Trinidad was received food in their preferred foraging habitat. The pos­ by the Frank M. Chapman Fund of the American sible second breeding period would coincide with Museum of Natural History, New York. Mist­ the petit careme, a time of similar increased flower netting and collection of specimens was authorized production and associated insect abundance by a Special Game License issued by the Trinidad (Snow and Snow 1964). This shifted breeding sea­ and Tobago Forest Department. I am happy to son could also be considered as a form of seasonal acknowledge the field companionship of Richard and spatial resource partitioning that reduces po­ and Margaret ffrench during my years in Trinidad. tential competitive interactions with other swifts for I am also indebted to D. W. Snow for first 'turning rainy season ae1ial insects. me on' to the joys and frustrations of field studies In Panama, Band-rumped Swifts apparently ofTrinidad swifts. S. L Warter and K. Garrett made breed in late February and March and a fully grown constructive comments on the manuscript and M. immature was collected on 28 March; the dry sea­ Marin provided comments and an advance copy of son is mainly between the late December and late his publication on these swifts for which I am April (Wetmore 1965, 1968). Although the moult of grateful. these swifts in Brazil is being completed during the dry season (see above), moult initiation and breed­ LITERATURE CITED ing would have been during the mid-December to April period of heaviest rainfall (Snow and Snow BEEBE, W. 1952. Introduction to the ecology of the 1964). Arima Valley, Trinidad, B. W. I. Zoologica A programme of monitoring Band-rumped 37:157-183. Swifts throughout the year would go a long way COLLINS, C. T. 1967. On a subterranean nest site of towards reinforcing the data presented here on the Short-tailed Swift in Trinidad. Oologists' their seasonal breeding and moult cycles. Chaetura Rec. 41:54-56. swifts are quick to utilise man-made equivalents of their nmmal hollow tree nest sites (Snow 1962, COLLLNS, C. T. 1968a. Notes on the biology of Co1li11s l 967, 1968a, 1968b ), including a nest box Chapman's Swift Chaetura chapmani (Aves, (Snow 1962) and artificial chimneys (Kyle and Kyle Apodidae). Amer. Mus. Novit. 2320:1-15. 1996). Thus it is reasonable to think that Band­ COLLINS, C. T. 1968b. The comparative biology of rumped Swifts potentially might utilise a series of two species of swifts in Trinidad, West Indies. miificial nest structures erected for them. This Bul1. Florida St. Mus. 1 I :257-320. would facilitate direct observation of their breeding COLLINS, C. T., AND E. L. BULL. 1996. Seasonal vari­ habits and other behaviours. Food brought to the ation in body mass of Chimney and Vaux's Biology ofBand-rumped Swifts 143

Swifts. N. Amer. Bird Bander 21:143-152. House SwiftApus affinis (G. E. Gray) 8. Breed­ FFRENCH, R. 1991. A guide to the birds of Trinidad ing seasons and theirregulation. Pavo 5:75-96. and Tobago. 2nd ed. Cornell University Press, PRIGOGINE, A. 1966. Note on Chapin's Swift. Bull. Ithaca, NY. 426 pp. Brit. Ornithol. Club 86:1-5. HILTY, S. L.,AND W. L. BROWN. 1986. A guide to the SICK, H. 1993. Birds in Brazil. Princeton University birds of Colombia. Ptinceton University Press, Press, Princeton, NJ. 836 pp. Princeton, NJ. 836 pp. SNOW, D. W. 1962. Notes on the biology of Trini­ KYLE, P. D., AND G. Z. KYLE. 1996. Swiftly dis­ dad swifts. Zoologica47:129-l39. appearing. Texas Parks Wild!. 54: 13. SNOW, D. W., AND B. K. SNOW. 1963a. Weights and MARIN, M. I 993. Pattems of distribution of swifts wing-lengths of some Trinidad birds. Zoo­ in the Andes of Ecuador. A vocetta 17:117-123 logica 48:1-12. MARIN, M. 2000. Species limits, distribution and SNOW, D. W., AND B. K. SNOW. 1963b. Breeding and biogeography of some New World gray­ the annual cycle in three Trinidad thrushes. rumped spine-tailed swifts (Chaetura, Apodi­ Wilson Bull. 75:27-41. dae). Omitol. Neotrop. I 1:129-144. SNOW, D. W., AND B. K. SNOW. 1964. Breeding sea­ MARIN A., M., CAJUUON, B., A.t'JD F. C. SIBLEY. 1992. sons and annual cycles of Ttinidad land birds. New distributional records for Ecuadorian Zoologica 49:1-39. birds. Omitol. Neotrop. 3:27-34. STILES, F. G. AND A. F. SKUTCH. 1989. A guide to MEYER DE SCHAUENSEE, R., AND W. H. PHELPS, JR. the birds of Costa Rica. Come]] University 1978. A guide to the birds of Venezuela. Press, Ithaca, NY. 511 pp. Princeton University Press, Princeton, NJ. 424 WETMORE, A. 1968. The birds of the Republic of pp. Panama. Part 2. Smithsonian Institution Press, NAIK,R.M.,ANDA. RAZACK. 1967. Studies on the Washington, DC. 605 pp. Pp. 144-154 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. II, 2002.

WEAVING TECHNIQUES IN TWO SPECIES OF ICTERIDAE, THE YELLOW ORIOLE (ICTERUS NIGROGULARIS) AND CRESTED OROPENDOLA (PSARACOLIUS DECUMANUS)

MYKELA HEATH AND MIKE HANSELL Department ofEnvironmental and Evolutionary Biology, Graham Kerr Building, University ofGlasgow, Glasgow GJ2 8QQ, UK

ABSTRACT.-African weaverbirds (subfamily Ploceinae) use a variety of weaving stitches in nest construction, which suggests that in these woven nests building behaviour is particularly complex. However, birds in several other families also make hanging nests of entangled vegetation, the most impressive being nests made by the New World orioles and oropendolas (family Icteridae). Examination of nests of the Yellow Oriole (Icterus nigrogularis) and Crested Oropendola (Psaracolius decu.manu.s) in this study demonstrates that a similar range of stitches are used by these species compared with the Ploceinae. The nests of both species, however, make particular use of two simple stitches, the half hitch and simple loop; both species also use a simple weaving technique. Spiral binding is shown by both species, but was at its highest density around the entrance of the nests of the Crested Oropendola. The difficulty of weaving compared to other techniques and the extent of its occurrence among birds are discussed.

RESUMEN.-Las aves tejedores (subfami lia Ploceinae) de Africa utilizan una variedad de puntadas tejedoras para Ia construcci6n de sus nidos, lo cual sugiere que el comportamiento de construir nidos avitelados es muy complejo. Sin embargo, hay aves de algunas otras familias que tambien hacen nidos suspendidos con vegetaci6n embrollada, las mas impresionantes son las de los conotos y turpiales (familla Icteridae) del Nuevo Mundo. En este estudio se examin6 los nidos del Gonzalito (Icterus nigrogularis) y el Conoto Negro (Psaracolius decumanus) encontrando que hay una ampla similitud entre las puntadas usadas por estas especies y los Ploceinae. En Ia construcci6n de sus nidos ambas especies utilizan particularmente dos puntadas sencillas, el nudo medic y ellazo sencillo y tambien usan una tecnica sencilla de tejer. Am bas especies usan elligaz6n espiral, cuya densidad fue mayor alrededor de Ia entrada del nido del Conoto Negro. Se discute aquf Ia dificultad de tejer comparada con otras tecnicas, y la ocurrencia de tejido entre las aves.

KEY WORDs.-crested Oropendola, Icteridae, lctems nigrogularis, nest con­ struction, Ploceinae, Psarocolius decumanus, Yellow Oriole, weaving techniques

'Weaverbirds' is a term used to describe mem­ ability to create a nest entirely from intertwined bers of the subfamily Ploceinae ofPloceidae (How­ pieces of vegetation, generally unsupported from ard and Moore 1991). The name refers to their below, so that the whole structural integrity and

144 Weaving Techniques in lcteridae 145 attachment of the nest depends upon the tightly families. However, it is clear that the Crested Oro­ interlocked vegetation strands (Crook 1960, Collias pendola (Psarocolius decumanus), in making its and Coll1as 1964a). To be able to construct a hang­ deep, suspended nest with strips of vegetation, ing nest in this manner requires some important uses a range of beak movements that might achieve skills. Firstly an ability to draw a single strand of a similar range of stitches (Drury 1962). The pur­ vegetation through the existing nest fabric, which pose of this paper is to examine the nests of two necessitates repeatedly pushing the same strand species of Jcteridae (American Ornithologists' under another, picking up the loose end, drawing it Union 1998), the Yellow Oriole (Icterus nigro­ through and then pushing it under again (Hansell gularis) and Crested Oropendola, in order to corn­ 1984). It also involves manipulative skill requiring a pare the nature and variety of their stitching tech­ mobile head, sharp eye a11d sensitive beak to loop niques with those reported in the Ploceinae and a vegetation strand under and around other ob­ therefore assess whether tl1ey exhibit comparable jects, both to create an attachment for the nest on building skills. In addition, this paper compares a fine twig and to build up the fabric of the nest construction techniques in different parts of the wall. nest of the two icterid species, and discusses the The name weaverbird is somewhat misleading prevalence of weaving as a nest building technique for the techniques used by the Ploceinae because in birds as a whole. the regular over-under technique which character­ ises human weaving is only recorded in one genus, METHODS Malimbus (Colli as and Colli as 1964a), and that only for the entrance tube. Crook (1960) describes three Four nests of the Yellow Oriole (nests 1-4) and categories of what he refers to as 'stitching' rather three of the Crested Oropendola (nests 5-7), both than 'weaving' in the Red-billed Quelea (Quelea common residents of Trinidad (ffrench 1991 ), were quelea); these are knotting, twining and weaving, collected in the vicinity of St. Augustine during where weaving describes the repeated insertion August 1996. All nests were then dried, weighed and pulling through of a strand until it is incor­ and sprayed with insecticide before being trans­ porated into the existing nest fabric. In a compara­ ported to Glasgow University for detailed exam­ tive study on the subfamily as a whole, Colli as and ination. Since nests were collected without the Colli as (1964a) extended the number of categories branches to which they had been attached, exam­ to nine: loop tuck, simple loop, interlocking loops, ination of the nest suspension was excluded from spiral coil, simple weave, alternately reversed the analysis of nest structure. winding, half hitch, overhand knot and slip knot. Nest weights and materials. -All nests were Collias and Colli as (1964b) demonstrated the weighed and then samples of the main vegetation role ofleaming in the development of nest building types, distinguished by general morphology, were skills in the Village Weaver (Ploceus cucullatus), removed from Yellow Oriole nest 3 and Crested but virtually no other expetimental evidence is Oropendola nest 6. These samples were identified available to assess the difficulty of nest building as closely as possible at the National Herbarium, for birds. Nonetheless, it seems likely that weaving University of the West Indies, St. Augustine, Trin­ with strips of plant material is among the more idad. difficult construction techniques, because the in­ Construction techniques: quadrat samples.­ tegrity of the nest depends not on the inherent Four areas of each nest were sampled to compare propetties ofthe materials to adhere to one another, construction techniques in different parts of the but on the stitching ability of the builder. For nest. These were: (a) top half face; (b) top half side; suspended nests, typical in plocei11e weavers, this (c) bottom half face; and (d) base (Fig. 1). Sampling imposes a challenge on the quality ofworkmanship. was carried out after the application of a template to The attention given to the weaving techniques the sample site in which was cut a rectangular 4x8 of Ploceinae has created the impression that they em window. Within the window the following have special skills unequalled by members of other feaures were scored: (1) number of half hitches 146 HEATH AND HANSELL

in each nest was chosen at random, according to Attachment whether their trajectory throughout a quadrat (se­ lected as described above) was predominantly in a vertical or horizontal orientation. Strands with their axes above 45o from the horizontal were scored as vertical strands, those below the c1itical angle, as horizontal. Data are displayed as the number of vertical strands. The path taken by a strand throughout the nest wall was detennined for 20 randomly selected strands from each nest by following each with a needle and coloured thread and then drawing the path within a drawing of the outline of the nest (Figs. 3A and 3B). Each trajectory was then cat­ A egorised as one of the following: (1) a straight line; (2) U-shaped; (3) S-shaped; (4) spiral shaped; (5) simple cross over; and (6) complex. All 20 strands were examined again and scored for the presence of a loop tuck (Fig. 2), i.e., if the strand had been taken and pulled through from the middle, not from the end. Length of strand.~.-The lengths of the vege­ tation strands used in building were determined by c carefully removing 30 strands from each of four lo­ cations in each nest: ( 1) base of nest-outside; (2) D base of nest-inside; (3) top half of the nest (thin wall making inside and outside indistinguishable); and ( 4) nest lining (where present). Lining of nest.-Where a lining was present it was removed, weighed and qualitative notes made of its composition. The presence of a lining was FIG. 1. Illustration JI a nest indicating the four areas easy to recognise because it was easily detached sampled with the quadrat: (A) top halfface; (B) top from the structural wall off the nest, made of dif­ half side; (C) bottom half face; and (D) base. ferent materials and assembled in a different man- ner. Rim ofnest entrance.-For each nest, the rim of (Fig. 2); (2) number of ends of strands; (3) number the nest entrance was also examined and scored for of loops (Fig. 2); ( 4) number of spiral coils (two or the presence of all weaverbird stitches recorded by more wraps around a central fibre; Fig. 2); (5) num­ Collias and Collias (I 964a). Qualitative notes were ber of strands passi11g through the quadrat without also made of the constmctional details. being crossed by any other strand (not crossed Analysis ofdata .- The small number of nests in over); and (6) density of stitches, an ordi11al meas­ the sample makes statistical analyses inappropriate. urement of how many hitches, loops and/or spiral However, the presence of the vatied stitch types twists were present, scored on a three point scale permits direct comparison with ploceine weavers, where: 0 = no stitches present; 1 =few of any oftl1e as described by Collias and Colli as ( 1964a), and the three stitch types; 2 =considerable number of any tables of data allow a qualitative assessment of a of the three stitch types. number of key features of the structure of nests in Weaving path.-The mientation of 20 strands the Yellow Oriole and Crested Oropendola. Weaving Techniques in lcteridae 147

Half Hitch Simple Loop Spiral Coil Loop Tuck

FIG. 2. Types of weaving stitches described by Colli as and Colli as (1964a}.

E u N L{) 0)

Yellow Oriole Crested Oropendola

FIG. 3. Examples of trajectories of 5 individual strands from nests of a Yellow Oriole and a Crested Oropendola.

RESULTS 5-7""' 170.0, 143.5 and 176.5 g, respectively). Nests of the Yellow Oriole were predominantly Nest weights and material.-The nests of the of strips of grass (family Poaceae), possibly includ­ two species exhibited both similarities and differ­ ing Vitiveria zizanoides. These were mostly from nces in their construction. The Yellow Oriole nests 1.0-1.5 mm in width and were interlaced with ami­ averaged less than half the weight ( x = 61.0 g; nority of aerial roots of aroids ( Araceae ), 1.5-2.0 mm nests 1-4 = 39.0, 81.0, 78 .0 and 46.0 g, respectively) in diameter. of the Crested Oropendola nests (x = 163.0 g; nests Nests of the Crested Oropendola were more 148 HEATH AND HA!'JSELL

TABLE 1. Number of weaving techniques used within a 4x8 em quadrat from four locations, both outside (out refers to counts made looking at the outside) and inside (in refers to counts made looking at the inside of the nest) the nests of the Yellow Oriole (nests 1-4 ).

Nest number 2 3 4 Technigue Out In Out In Out In Out In A. Number of half hitches (Fig. 2) Top half face 8 4 0 10 1 Top half side 10 9 5 0 4 3 5 2 Bottom half face 1 0 5 0 5 1 9 0 Base 0 0 2 0 0 0 0 0 B. Number of loops (Fig. 2) Top half face 8 2 2 0 6 4 Top half side 2 0 4 0 2 2 2 Bottom half face 1 1 0 2 4 1 Base 0 3 0 0 2 0 C. Number of spiral coils (Fig. 2) Top half face 0 0 1 0 0 2 1 Top half side 0 0 0 0 0 0 Bottom half face 0 0 0 0 0 0 0 Base 0 0 0 0 0 0 D. Number of pieces of nest material that are not crossed over by any other piece Top half face 0 I 0 0 0 0 0 0 Top half side 0 0 0 0 2 0 0 0 Bottom half face 0 0 I 1 3 I Base 0 0 0 0 2 0 2 0 E. Density of half hitches, loops and/or spiral coils Top half face 2 2 0 2 2 Top half side 2 1 0 1 2 Bottom half face 0 0 I 2 0 Base 0 0 0 0 1 0 F. Number of ends Top half face 9 6 6 14 12 12 16 12 Top half side 2 10 7 4 19 6 12 11 Bottom half face 9 8 8 5 9 4 7 11 Base 12 9 8 6 10 5 6 4

varied in species and in the width of the strips. four positions, both outside and inside the nest, are They contained snips of leaves of grasses (Poa­ presented for the Yellow Oriole and Crested Oro­ ceae) including !schaemum timorense, sedges (Cy­ pendola in Tables 1 and 2, respectively. peraceae), and palm leaf (Arecaceae). Stems of The weaving stitches maintaining the fabric of some leguminose species {Fabaceae) were also Yellow Oriole nests are largely half hitches and present as were aerial roots of aroids (Araceae). loops with a small number of spiral coils. The den­ The strands varied in width from< 1.0 to> 4.0 mm. sity of all three of these is distinctly lower in the Construction techniques: quadrat samples.­ bottom half and especially the base of the nest (Ta­ The number of weaving techniques for quadrats in ble lA-C). Also, in all four quadrat locations, the Weaving Techniques in lcteridae 149

TABLE 2. Number of weaving techniques used within a 4x8 em quadrat from four locations, both outside (out refers to counts made looking at the outside) and inside (in refers to counts made looking at the inside of the nest) the nests of the Crested Oropendola (nests 5-7).

Nest number 5 6 7 Technique Out Jn Out In Out In A. Number of half hitches (Fig. 2) Top half face 21 9 13 4 23 6 Top half side 19 3 5 6 19 3 Bottom half face 6 8 31 0 17 7 Base 0 0 0 0 0 B. Number of loops (Fig. 2) Top halfface 2 2 7 5 4 I Top half side 4 3 3 0 5 0 Bottom half face 2 4 3 0 2 1 Base 0 0 2 3 0 3 C. Number of spiral coils (Fig. 2) Top half face 0 0 0 0 0 0 Top half side 0 0 0 0 0 Bottom half face 0 0 0 0 0 0 Base 0 0 0 0 0 0 D. Number of pieces of nest material that are not crossed over by any other piece Top halfface 0 0 0 2 0 0 Top half side 0 0 0 I 0 1 Bottom halfface I 0 2 0 0 Base 1 0 0 0 0 E. Density of half hitches, loops and/or spiral coils Top half face 2 2 2 2 Top half side 2 I I 2 0 Bottom halfface l 2 2 0 2 1 Base 0 0 1 0 0 0 F. Number of ends Top half face 12 3 8 4 8 8 Top halfside 6 10 5 5 3 5 Bottom half face 3 7 4 4 6 6 Base 7 4 5 6 3 5

density of these three stitches appears lower on the bottom half and base of the nest is not only reflect­ inside of the nest wall than on the outside (Table ed in the individual scores of the three stitches lA-C). The nest fab1ic is also maintained by simple (half hitch, loop and spiral coil), but also in the weaving in which strands are passed under other score density, which summarises their overall abun­ strands present in the nest wall. This is probably dance (Table I E); it is also illustrated by the slight­ the chief way in which the nest maintains its in­ ly higher score for not crossed over in the bottom teg~.ity and is illustrated by the low values of not half and base than in the top half (Table lD). The crossed over i11 all quadrat sites {Table I D). The frequency of strand ends, however, seems much greater simplicity of the weaving technique in the the same in all parts of the nest (Table 1F), suggest- 150 HEATH AND HANSELL

TABLE 3. Number of strands out of 20 passing through a quadrat scored as vertical for nests of the Yellow Oriole and Crested Oropendola. An axis more than 45o above the horizontal scored one for vertical, and 45° or below scored as zero (i.e., horizo11tal).

Nest number 2 3 4. Species I Technique Out In Out In Out In Out In Yellow Oriole Top half face 17 16 18 19 16 15 10/10 0 Top half side 10 19 20 20 15 20 10/10 0 Bottom half face 18 6 17 18 19 13 7110 0 5 6 7 Out In Out hl Out In Crested Oropendola Top half face 16 18 20 17 16 18 Top half side 20 18 17 20 15 17 Bottom half face 16 20 10 18 15 16 "based on a sample of only 10 strands ing that there is no special place for beginning or or doubling back to cross over the initial path ending the i11sertion of strands. (Table 4). S-shaped or spiral tracks were more rare, The fabric ofthe nests of the Crested Oropen­ but a minority of paths were sufficiently complex to dola contained a density of half hitches more than include an S-shaped trajectory with crossing over twice that in the Yellow Oriole nests (inside and (complex). The final distinctive feature of the in­ out; Table 2A). Loops also were at least as frequent sertion of strands in this species was evidence in as in Yellow Oriole nests in both the top and bot­ nearly a quarter of them that, instead of being tom halves of the nest, outside and in (Table 2B). grasped at its end, the strand had been held with Spiral coils were v1rtually absent from the sides of ends projecting from both sides of the bird 's beak the nest, upper and lower half (Table 2C). The base when inserted (a loop tuck; Fig. 2). of the nest was almost devoid of all the three weav­ The insertion of strands in nests of the Crested ing stitches, a feature reinforced by the low score Oropendola was, as in Yellow Oriole nests, dom­ of density in the base compared with other regions inated by a U-shaped path with simple straight (Table 2E). In the base were strands held together paths almost as common. Crossover or complex by simple weaving; the not crossed over figures for paths taken together were about as common as in all nest regions were low, as in the Yellow Oriole Yellow Oriole nests, with S-shaped and spiral paths (Table 2D). The frequency of ends of strands was slightly more so (Table 4). A more obvious differ­ neve11heless about the same in all nest regions ence with Yellow Orioles was the low level of in­ (Table 2F), as in the Ye11ow 01iole. sertions in wl1ich the stra11d had not been held at Weaving paths.-The predominant orientation the end (loop tuck; Table 4). of strands in the nests of both species was vertical Lengths of strands.- T11e strands were general­ (Table 3). The high proportion of vertical strands in ly longest 011 the outside base and shortest on the the nests of the Crested Oropendola is particularly inside base for nests of both species, but averaged evident, reflecting the elongation of its nest com­ lo11ger in all measured locations for the Crested pared with that ofthe Yellow Oriole. Oropendola (Table 5). In the Yellow Oriole, the path of inse11ion of Lining ofnest .- Three of the four Yellow Oriole individual strands was frequently U-shaped with a nests had a distinct, easily detachable lining in the lesser proportion inserted in a simple straight line base of the nest cavity, comprising 7.7%, 10.5% Weaving Techniques in Icteridae 151

TABLE4. Path of weaving in Yellow Oriole and Crested Oropendola nests.

Path of Weaving Simple Loop SEecies I Nest Straight U-shaEed S-shaEed SEiral cross over ComE lex tuck Yellow Oriole Nest 1 4 6 2 0 2 6 6 Nest2 6 5 2 3 2 2 8 Nest 3 4 7 0 6 2 4 Nest 4 3 3 0 0 3 1 0 Crested Oropendola Nest 5 3 3 5 2 3 4 3 Nest 6 6 8 0 1 4 0 Nest 7 5 6 3 4 I

TABLE 5. Mean length (em± SE) of a sample of30 strands carefully removed from four locations (outside and inside of the base, the lining [when present] and the top half of the face of the nest) in Yel1ow Oriole and Crested Oropendola nests.

Location Species I Nest Outside base Inside base Lining ToE half face Yellow Oriole Nest I 26.94 ± 2.11 14.38 ± 1.54 23.18 ± 2.27 21.65 ± 2.51 Nest 2 28.59 ± 2.08 13.39 ± 1.15 22.42 ± 1.65 30.21 ± 4.68 Nest 3 33.42 ± 3.81 15.49 ± 1.46 8.35 ± 0.81 27.52± 3.01 Nest4 30.61 ± 3.29 6.45 ± 0.54 none 16.66 ± 1.84 Crested Oropendola Nest 5 43.30 ± 4.32 17.80 ± 2.01 none 32.15 ± 3.60 Nest 6 26.45 ± 3.10 22.72 ± 3.08 none 35.15 ± 3.56 Nest 7 25.86 ± 2.64 28.90 ± 2.75 28.68 ± 1.72 37.83 ± 3.91 and 4.2% of the nest weight, respectively. These lining of Yellow Oriole nests. Nests 5 and 6 were linings were different in composition from the struc­ similar in containing deciduous leaf linings resem­ tural wall of the nest and were very similar in all bling that described by Drury (1962). One nest of three nests, being of fine, springy, palm leaf fibres the Crested Oropendola (nest 7) had a lining of fine 6-15 em long, with a few grass stems. These were palm fibres underneath the deciduous leaves, loosely coiled in the base of the nest to form a dis­ closely resembling those found in Yellow Oriole tinct pad about 3 em thick. They were not inter­ nests. This may have been inserted by a Yellow locked with half hitches, loops, spiral coils or in Oriole attempting to usurp the nest; more likely, any other identifiable way. Nest 4 had no lining; Crested Oropendolas may construct more than one either the nest had not been completed or a hning type oflining. The lining comprised 23.5%, 12.9% is not always included. and 36.7% of the weight for each nest, respectively. In Crested Oropendola nests a hning of frag­ Rim of nest entrance.-In nests of the Yellow mented pieces of some deciduous tree was present Oriole, the rim of the entrance was not marked by in all, contrasting in appearance with the palm fibre any change in the style of the fabric. A single 152 HEATH AND HANSELL spiral coil was located in the rim of two of the technique is not favoured by Crested Oropendolas, nests, each of two or three turns, but small numbers which seem to hold strands almost entirely by their of these were found in other parts of the nest ends. Both species favour U-shaped paths for their (Table 1). The rim of the nest in Yellow Orioles is strands, with straight paths the next most common. not distinguishable in the type or quality of its Both species will also use more elaborate trajec­ workmanship compared with other parts of the tories including S-shapes, crossing over or both nest. combined when inserting a strand. The rim of the Cre.sted Oropendola nest en­ Spiral coiling is a technique in which the same trance was strikingly defined by an abundance of end is passed repeatedly under the axis of another spiral coils giving a very strong, thickened rim. strand or strands. It is reported in the Red-billed Single strands sometimes spiralled around a sma!l Quelea (Quelea quelea; Crook 1960) and Vi11age bundle of other fibres, sometimes around a single Weaver (Ploceus cucullatus; Collias and Collias strand. The number oftums in the coil was general­ 1962). Because it requires repeated inserting, re­ ly three or four, but coils of five or l 0 were also leasing, grasping and tightening of the end of the present. Other fastening stitches were also present same strand, spiral coiling illustrates especially well in the rim construction, including half hitches and the manipulative skill shown by birds that make interlocking loops. woven nests. Drury ( 1962) describes how the re­ peated peck-pull around-tuck action of the Crest­ DISCUSSION ed Oropendola working on the lower nest rim achieves a 'buttonhole-like' stitch. This highlights In his desctiption of the 11est building se­ the fine workmanship shown by Crested Oropen­ quence of the Crested Oropendola, Dmry (1962) dolas in the construction of the nest entrance rim. distinguishes between two basic behaviour pat­ Oropendolas and caciques are highly dimorphic terns: peck-pull around-tuck and horizontal peck­ with males much larger than females (Dunning pull-poke. In the former, the bird reaches around 1992). In the Crested Oropendola, as in most of its part of the nest or nest attachment to grasp an end relatives, the nest is built by the female (Drury that it pulls toward itself and pushes back into the 1962). Nevertl1eless, at 150 g, she is considerably nest fab1ic. In the latter, the bill is pushed through heavier than the Quelea, a typical ploceine weaver the nest fabric to grasp a strand which is then that weighs < 20 g. The use of spiral coils by Crest­ pulled back through, then pushed through again at ed Oropendolas in the entrance rim contrasts with a point somewhat to the side. The exact nature of their virtual absence from the rest of the nest. these two patterns varies depending on the part of Colhas and Collias (1964a) recorded complex the nest being constructed and there are other trajectories for single strands such as in the wall of somewhat distinct movements; however, the reper­ the nest of the Baglafecht Weaver (Ploceus bagla­ toire appears limited. What these descriptions do fecht), which shows multiple crossing over and true not reveal are the actual trajectories of the strands knots. More detailed examination of the nests of through the nest wall. This would require careful tropical icterid weavers may reveal this level of examination ofthe nests themselves, whicl1 was the complexity. This is most likely to occur in the nest target of our st11dy. attachment which has to accommodate the varied Our observations on Yellow 01iole and Crested geometry of tree branches (Nickell 1958). Examina­ Oropendola nests confi1m the presence of simple tion of the nest attachment was not possible in our weaving, half hitches, simple loops and spiral coils study, thus its level of complexity still awaits study. (Collias and Colli a:.; 1964a) in the nest construction Differences in construction of different parts of repertoire of both species. The Yellow Oriole also the nest are evident in the nests of both the Crest­ tends to use the loop tuck, a technique involving ed Oropendola and the Yellow Oriole. Their con­ the holding of the strm1d some way removed from struction is similar in the near absence of any tech­ either end so that, when it is passed through the nique other than simple weaving in the base of the fabric of the nest, it doubles up {Fig. 2). This nest. These details in architecture in different parts Weaving Techniques in Jcteridae 153 of the nest 111ustrate the need for further investiga­ judge more fully the difficulty of this technique tions to understand their function and cost. compared with others. Special demands are placed upon hanging nests since failure under tension will lead to com­ ACK.!'IOWLEDGEMENTS plete brood loss. Many small birds use silk in their nests (Colhas and Colhas 1984). This readily en­ We thank all members of the Glasgow Uni­ tangles with plant materials like mosses by virtue of versity Trinidad expedition ( 1996) for their help and the 'Velcro principle' (Storer and Hanselll992). The support, the University of the West Indies Catholic spider silk and moss wall of the nest of the Long­ Chaplaincy from where most of the nests were tailed Tit (Aegithalos caudatus) is constructed of collected in St. Augustine, and the Cross Trust these materials and Tinbergen ( 1953) remarks on Fund wl10se contribution made the collection of the the simplicity of the building behaviour required. It nests possible. Also, special thanks to M. P. could be argued from the account of Drury (1962) Cottam, J. R. Downie, D. C. Houston, D. B. McNair that construction by weaving is similarly simple for and V. C. Quesnel for their constructive comments the Crested Oropendola. However, its basic move­ in reviewing this manuscript. ments do not appear from Drury's description to be stereotyped and, in showing a similar range of LITERATURE CITED stitches to those shown in Ploceine weavers among which learning is known to occur (Collias and AMERICAN ORNITHOLOGISTS' UNION. 1998. Check­ Collias 1964b), learning should also be suspected. Jist ofNorthAmerican Birds. 7th ed. American Examination of nests in museum collections Ornithologists Union. Washington, DC. 829 (Hansell unpubl. data) also reveals that there are pp. members of four other families that construct COATES, B. J. 1990. The birds of Papua New Guinea. hanging nests solely of intertwined vegetation and Vol. II. Passerines. Dove Publications, Alder­ might therefore be showing at least some of the ney, Australia. 576 pp. techniques described in Old World weaverbirds, COLLIAS, N. E., AND COLLIAS, E. C. 1962. Experi­ Ploceinae. These are the small family Eurylamidae mental study of mechanisms of nest building (e.g., African Broadbill [Smithornis capensis], in a weaverbird. Auk 79:568-595. Thamnophilidae (e.g., Dusky Antbird [ Cercomacra COLLIAS, N. E., AND COLLIAS, E. C. 1964a. Evolution tyrannina], Tyrannidae (e.g., becards, Pachyram­ of nest building in weaverbirds (Ploceidae). phus spp.) and Sturnidae (e.g., Metallic Starling Univ. Calif. Pub!. Zool. 73:1-162. [Aplonis metallica}). Similar nests are also reported COLLIAS, E. C., AND COLLIAS, N. E. 1964b. The for members of two other families, Pomatostomati­ development of nest building behaviour in a dae (Rufous Babbler [Pomatostomus isidorei]; weaverbird. Auk 81 :42-52. Coates 1990) and Furnariidae (Red-faced Spinetail COLLIAS, N. E., AND COUJAS, E. C. 1984. Nest build­ [Cranioleuca erythrops]; Wetmore 1972). There is ing and bird behaviour. Princeton University also clearly a need for further comparative studies Press, Princeton, NJ. 336 pp. on nest weaving birds from the smaller species (at CROOK, J. H. 1960. Nest form and construction in around 20 g) such as ploceine weavers and becards certain West African weaverbirds. Ibis 102:1- (Tyrannidae), intermediate species (at around 60 g) 25. such as the Metallic Starling (Dunning 1992) and DRURY, W. H. 1962. Breeding activities, especially the much larger icterid weavers where females may nest building of the Yellowtail ( Ostinops decu­ reach up to 225 g (Dunning 1992). Differences manus) in Trinidad, West Indies. Zoologica47: between species may then provide insights into, for 39-58. example, the effectiveness of different stitches for DUNNING, J. B. 1992. CRC Handbook of Avi an Body birds of different sizes. There is also a need for a Masses, CRC Press, Boca Raton, FL. 371 pp. detailed study of the development of stitching !'FRENCH, R. 1991. A guide to the birds of Trinidad behaviour to determine the role of learning and so and Tobago. 2nd ed. Cornell Uuiversity Press, 154 HEATH AND HANSELL

Ithaca, NY. 426 pp. isation in the choice and use of silk in the nest HANSELL, M. H. 1984. Animal architecture and of the chaffinch (Fringilla coelebs) Aves Frin­ building behaviour. Longman, London. 332 pp. gillidae. J. Nat. Hist. 26:1421-1430. HOWARD, R., AND MOORE, A. 1991. A complete TINBERGEN, N. 1953. Specialists in nest-building. checklist of the birds of the World. Academic Country Life 30:270-271. Press, London. 622 pp. WETMORE, A. 1972. The birds of the Republic of NICKELL, W. P. 1958. Variations in engineering Panama. Part 3. Passeriformes: Dendrocolap­ features of the nests of several species of birds tidae (Woodcreepers) to Oxyruncidae {Sharp­ in relation to nest sites and nesting materials. bills). Smithsonian Institution Press, Wash­ But. Univ. Bot. Stud. 13: 121-140. ington, DC. 631 pp. STORER, N. P ., AND HANSELL, M. H. 1992. Special-

Crested Oropendola (Cacicus decumanus). Illustration by Edward Rooks. Pp. 155- 165 in Studies in Trinidad and Tobago Omithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci ., Univ. West Indies, St. Augustine, Occ. Pap. 11 ,2002.

MATING AND NEST-SEARCHING BEHAVIOUR OF SHINY COWBIRDS ASSOCIATED WITH DIFFERENT HOST SPECIES IN TRINIDAD AND TOBAGO

TIM MANOLJS1 AND ALEXANDER CRUZ2 1808 El Encino Way, Sacramento, CA 95864-5218, USA ~Departm e nt ofEnvironmental, Population and Organismic Biology, University of Colorado, Boulder, CO 80309-0334, USA

ABSTRACT.-The Shiny Cowbird (Molothrus bonariensis) is a brood parasite of a wide variety of passetine species in South America and the Caribbean region. We examined the mating and nest-searching behaviour of cowbirds parasitising vatious hosts in different environments in Trinidad and Tobago. Breeding cowbirds congregate at nesting colonies of Yellow-hooded Blackbirds (Agelaius icterocephalus) in marshes in Trinidad in the rainy season. Most female cowbirds visiting territmies and nests of blackbirds do so singly or in groups of two or more females. Little evidence of cowbird pair fonnation was observed at blackbird colonies. We observed a different pattern of cowbird mating behaviour i11 mral areas of mixed agricultural plots and woodland, where House Wrens (Troglodytes aedon), which have more uniformly dispersed nesting attempts than the colonial blackbirds, are the primary host. At one such site, we documented stable pair formation over a period of a few weeks within a small population of colour-banded cowbirds. Cowbirds also showed a greater likelihood to visit House Wren nests and territories in male-female pairs than for other potential hosts. Combining various lines of evidence (grouping patterns, mating and nest-searching behaviour, and pair formation amm1g colour-bm1ded birds) offers some support for a hypothesis that cowbirds are promiscuous where host (and cowbird) densities are highly clumped (e.g., blackbird colonies), and monogamous where hosts are fairly common but uniformly dispersed (e.g., House Wren territories). Shiny Cowbird mating behaviour seems to show considerable flexibility, both within and between populations. More extensive studies with a greater range of ho sts over a broad range of habitats throughout the cowbird's range are warranted to elucidate the effects of host type and availability, as well as other ecological factors, on its mating behaviour.

RESUMEN.- EI Tordo Mirlo (Molothrus bonariensis) es una ave que panisita a una amplia variedad de especies paserinas en Sudamerica y el Caribe. Examinamos los com­ p01iamientos de acoplamiento y blisqueda de nidos del tordo a! parasitar varios hues­ pedes en ambientes diferentes en Trinidad y Tobago. Durante Ia epoca de anidaci6n, que coincide con Ia temporada de lluvia, los tordos se congregan en las colonias reprodnctivas del Turpial de Agua (Agelaius icteroceph alus) en los pantanos de Trinidad. La mayo ria de hem bras del tordo que visitan los territories y nidos del turpial lo hacen solas o en grupos de dos o mas hembras. Poca evidencia de formaci6n de parejas macho-hembra del tordo fue observada en las colonias del turpial. Observamos en el tordo un patron diferente de apareamiento en las areas rurales (terrenos de

155 156 MANOLIS AND CRUZ

agricultura mezclados con bosques) donde el Cucarachero Comtm (Troglodytes aedon), quien distribuye sus intentos de anidaci6n mas uniformemente dispersos que el tur-pial, es el huesped prima1io. En uno de dichos lugares documentamos Ia formaci6n estable de parejas durante un periodo de semanas en una poblaci6n de tordos anillados. Los tordos tambien mostraron una mayor tendencia a vi sitar en pareja los nidos y territorios del cucarachero que el de otros huespedes potenciales. Combinando varias lineas de evidencia (patrones de agrupamiento, acoplamiento, comportamiento de busqueda de nidos y fmmaci6n de parejas entre aves anilladas) hay una tendencia que soporta Ia hip6tesis que los tordos son promiscuos cuando los densidades de los huespedes (y tordos) son sumamente agmpadas (e.g., colonias del turpial), y monogamos cuando los huespedes son comunes pero uniformemente dispersos (e.g., territorios del cucar­ achero). El Tordo Mirlo muestra flexibilidad considerable, tanto dentro como entre poblaciones. Estudios mas intensivos con mas huespedes, sabre una escala mas amplia de habitats y a n·aves de todo el area de distribuci6 del tordo son necesarios para aclarar los efectos de tipos y disponibilidad de huespedes, asi como otros factores ecol6gicos, en su comportamiento de apareamiento.

KEY WoRDs.-brood parasitism, mate attendance, mating behaviour, mating systems, Molothrus bonariensis, nest-searching behaviour, Shiny Cowbird

The Shiny Cowbird (Molothrus bonariensis) in Wittenberger and Tilson 1980). Gochfeld (1977) of South America and the Caribbean region, in­ and Ankney and Scott (1982) hypothesised that cluding Trinidad and Tobago, and the Brown­ cowbirds might employ a mix of different mating headed Cowbird (M ater) of North America lay systems in some or most populations, and there their eggs in the nests of many species of birds, of has been support for this in some recent studies which most are passerines (Friedmann et al. 1977, (Rothstein eta!. 1984, 1986, Teather and Robertson Ortega 1998). These cowbirds appear not to be 1986, Yokel1989). Gochfeld (1977) and Elliott (1980) strongly specialised in terms of host selection, and also speculated that differences in habitats and are perhaps the most generalised of avian brood host densities might be responsible for the differ­ parasites (Ortega 1998, Cmz eta!. 1998). Studies of ences observed in Brown-headed Cowbird mating Brown-headed Cowbird social structure have vari­ systems in different regions of North America. ously indicated that it may be primarily mono­ Friedmann (1929) suggested that Shiny Cowbirds gamous (F1iedmann 1929, Laskey 1950, Darley 1978, were primarily monogamous but tended towards 1982, Dufty 1982, Yokel 1986), polygynous (Payne promiscuity in areas of high cowbird density, a 1973, Teather and Robertson 1986) or promiscuous pattern confirmed for Brown-headed Cowbirds by (Gochfeld 1977, Elliott 1980). The Shiny Cowbird Yokel (1989). This pattern, however, begs the has also been characterized as being either primari­ question of what factor(s) influence(s) the density ly monogamous (F1iedmann 1929) or promiscuous of breeding cowbirds in an area. (Mason 1980, 1987) in different parts of its range, Mason (1980) developed a model ofbrood par­ but this species' mating behaviour has not been as asite mating systems in which the dispersion of rigorously investigated as has its North American host nests is the major variable influencing cowbird congener's (Ortega 1998). breeding behaviour, given that the distribution of The freedom from parental care that a brood food or any other resources does not limit the ac­ parasite enjoys has been suggested as the major tivities or local densities of cowbirds (e.g., Cronin factor that might allow such unusual (for a pas­ and Sherman 1977, Rothstein et al. I 984). Where serine bird species) flexibility in the mating beha­ preferred hosts are primarily small and their nests viour of both sexes of cowbirds (e.g., see Gochfeld widely or unif01mly dispersed, the model predicts Shiny Cowbird Mating Systems 157

that monogamy may be a viable strategy. Because bird are restricted to tl1e rainy season (Snow and a male cannot effectively associate himself with a Snow 1964, ffrench 1980, Cruz et al. 1990). Thus, the large number of host nests or females (which will dispersion of available nests for cowbirds to para­ also be dispersed), his best strategy may be to sitise in marshes versus in mixed-agricultural dis­ follow a female searching for nests and guard her tricts is much more clumped temporally as well as from other males. A female may tolerate a male fol­ spatially. lower because he serves as a decoy, distracting In this paper, we predict that cowbirds para­ host aggression (Mason 1980), because he helps sitising dispersed nests in rural areas of mixed agri­ flush nesting birds or otherwise helps detect host culture, where House Wrens are the predominate nests (Young 1929), or because he protects her host, will be primarily monogamous, whereas cow­ from harassment by other male cowbirds (Ankney birds parasitizing Yellow-hooded Blackbird colon­ and Scott 1982, Darley 1982). Where host nests are ies in marshes will be promiscuous. To this end we clumped (e.g., in colonies or where preferred hosts evaluate data collected on (1) social grouping pat­ are locally abundant), a male is less assured of his terns of cowbirds, (2) behaviour of colour-marked paternity by not guarding a single female, but pre­ birds, (3) nest-searching and host-watching beha­ sumably his association with a high density of host viour, and ( 4) comiship and copulation. We collect­ nests (which should attract a large number of fe­ ed these data incidental to the primary focus of our males) results in enough matings with a variety of field work on cowbird-host interactions (Manolis females to offset this disadvantage. 1982, Cruz et al. 1990); thus, sample sizes are ad­ Territories of one preferred host in Tlinidad mittedly small. Although these data offer no con­ and Tobago, the House Wren (Troglodytes aedon), clusive proof of Shiny Cowbird mating systems, are fairly uniformly dispersed in rural, wooded and they offer some evidence of these, and we hope agricultural environments, whereas another com­ they will stimulate fmiher, more intensive work in monly used host, the Yellow-hooded Blackbird this area. (Agelaius icterocephalus), is colonial and polygy­ nous in marshes (Wiley and Wiley 1980, Manolis STIJDY AREAS 1982, Cruz et al. 1990). Scattered pairs ofthe black­ bird breed in small marshes in rural ag~icultural dis­ Data evaluated herein were collected in four tricts, where tl1eir dispersion is similar to that of the different areas during the periods of 12 June - I wren. A third preferred host ofthe cowbird in Tlini­ August 1979, II May- 18 August 1980,2 April- 13 dad is the Red-breasted Blackbird (Leistes mili­ May 1981, and 8 September- 25 October 1981 (see taris), which is usually monogamous, occasionally Manolis 1982 for additional information), although polygynous (Haverschmidt 1968, Manolis pers. not all types of data were collected at every site in obs.), and not truly colonial, but tends to form local every season. Sites studied were: breeding aggregations in pastures and other open, (1) The University of the West Indies Experi­ grassy areas. An adult House Wren (body mass x mental Farm (UWI Farm), 3 km west of the U\VI = 14.3 g on Trinidad [n = 31] and 15.8 gon Tobago Campus in St. Augustine, T1inidad. The farm con­ [n = 6]; ffrench 1980) is less than half the size of an tains extensive open pastures, crop fields m1d or­ adult cowbird (males= 39.9 g [n = 16], females = chards, and some animal pens and other farm 36.0 g [n = 16]; this study), whereas Yellow-hooded buildings. Red-breasted Blackbirds breed here in Blackbirds (males=35.9 g [n = 32], females = 26.8 g the pastures, and House Wrens in the orchards and [n = 18]; ffrench 1980) and Red-breasted Blackbirds around buildings. (43.38 g [n = 4; 3 males and 1 unsexed]; ffrench (2) The Jauque Seeyave Farm (JS Farm), 0.33 1980) are similar in size to their brood parasite. km southeast of the village of Carapo in north­ House Wrens and most other potential hosts central Trinidad. The fmm consists of orchards, in rural districts of Trinidad and Tobago have pro­ bmshy fields and large chicken pens. House Wrens longed or year-round breeding seasons, whereas are common breeders in this habitat. To the north large nesting colonies of the Yellow-hooded Black- and west of the farm are freshwater marsh and ------

158 MANOLIS AN D CRUZ

swamp forest bordering the Manacal River. A few, sites was assessed by observations of: (1) male scattered tenitories of Yellow-headed Blackbirds courtship display and song (including song given are found in these marshes. Immediately to the in the hand, particularly in conjunction with physi­ northeast is Malabar Farm, with extensive pastures ological evidence of breeding activity, e. g., cloacal for horses and cattle, where Red-breasted Black­ protuberance) and a harsh, rattle call of females birds are fairly common breeders. almost exclusively associated with breeding con­ (3) Freshwater marshes along the Princess dition (Payne 1973, Manolis pers. obs.); {2) copu­ Margaret Highway (PMH site) bordering the Caroni lations; (3) cloacal protuberances in males and ovi­ Swamp on the west coast of Trinidad. Interspersed ductal eggs in females of captured birds, assessed in these marshes are active and fallow rice paddies by tactile examination; and (4) nest-searching beha­ as well as small, agricultural plots. Large colonies of viour. For further elaboration on nest-searching Yellow-headed Blackbirds breed in these marshes behaviour, see Wiley (1988) and Cruz et al. (1990). in the rainy season. (4) Teny Hill Estate, 3 km north of Mount St. RESULTS George in south-central Tobago. The estate con­ sists of a mix of small agricultural plots and or­ Grouping patterns.-Periodic censussing indi­ chards, small pastures, and second-growth wood­ cated that cowbirds were more frequently encoun­ land surrounding a hilltop home flanked by four tered in pairs at Terry Hill and at the JS Farm in immense, epiphyte-laden saman trees (Pith ecel­ summer 1980 than at the PMH site in 1980 or the JS lobium saman). The House Wren is a common host Farm in spring 198 1 (Table 1). The differences may in this area, but neither blackbird species is present. seem slight but are actually quite striking in light of differences in cowbird population stmcture be­ MEDfODS tween sites. A 11 of the cowbirds (excluding nest­ litlgs, not included in Table 1) seen at the PMH site Censuses were conducted regularly at all sites in 1980 were in breeding condition (engaged in to determine the relative abundance and breeding courtship, copulation, nest-searching, etc.), hence status of populations of the cowbird and potential the frequency of observed pairings might be a rea­ hosts. During frequent walks through study areas sonable estimate of actual pairings, even for single or dming stationaty observations made at blackbird copulations. On the other hand, many of the cow­ colonies or feeding sites, the location and beha­ birds seen at the JS Farm (and included in Table 1) viour of cowbirds and potential hosts was noted were non-breeders. For example, seven of23 (30%) and plotted on maps. Gridded maps of some study birds colour-banded at the JS Farm were in juvenal sites were made by measuring and marking off g1id plumage or moulting from juvenal to first-year coordinates either 10 or 25 m apart. Maps for other plumage. The frequency of pairing among breeding sites were derived from topographic maps (I : 10,000 adult cowbirds is thus perhaps underestimated for and 1:25,000 scale) obtained from the Trinidad and this area in Table 1. Few if any of the observed Tobago Department of Lands and Surveys. Host pairs could have been of non-breeding birds, as territories and nests were plotted and nesting one of our criteria for defining a pair was that one attempts of potential hosts were numbered and or both birds gave evidence of being in breeding monitored. Cowbirds were captured with mist-nets condition, usually by its behaviour. and colour-banded at the JS Farm. The names given Observations of colour-banded birds.-Four­ birds in thi s paper are abbreviations of their band teen cowbirds (seven adult males, two first-year combinations. Initials used are: Y = yellow; 0 = males, four adult females, and one unsexed juve­ orange; G =green; R = right leg; L = left leg. For nile) were colour-banded at the JS Farm during the example, GRYL was banded green on the rigllt leg period 3 July- 8 August 1980. Three of these birds and yel!ow on the left; YROR was banded yellow were never resighted, including the juvenile bird on top of orange on the right leg, etc. and a male molting from juvenal to first-year plum­ The breeding status of cowbirds at various age. The latter two may have been post-fledging Shiny Cowbird Mating Systems 159

TABLE 1. Grouping patterns of Shiny Cowbirds (Molothrus bonariensis) at three study sites in Trinidad and Tobago.

Number of Observations£% of Total at Site) Site 1 cowbird rJ/'f pair d'I 'f groups" >2 females >2 males Total Terry Hill (1980) 25 (69.4) 8 (22.2) 2 (5.6) 1(2.8) 36 JS Farm (1980) 35 (56.5) 15 (24.2) 2 (3.2) 3(4.8) 7(11.3) 62 JS Farm (spring 1981) 121 (70.8) 29 (17.0) 13 (7.6) 4{2.3) 4{2.3) 171 PMH Site (1980) 44 (58.7) 11 (14.7) 14 (18.7) 1(1.3) 5(6.7) 75 "groups of three or more birds of both sexes (see text) dispersers and not part of the resident cowbird Nest-searching behaviour.-Shiny Cowbirds population. At least nine, probably ten, of the cow­ exhibited different social behaviour when searching birds banded in 1980 were resighted in spring 1981, for and examining nests of different hosts (Table 2). including all four females. Three of these females Female cowbirds usually entered Yellow-hooded were seen in fal11981. None ofthe males banded in Blackbird territories at marsh colonies alone, but 1980 was seen in fall I981. were also seen entering colonies in association Two of the four females banded in 1980 (YR with other females. In one instance, a female cow­ and OROL) were repeatedly observed being fol­ bird flew to a blackbird nest under construction lowed by single males (ORYRand OR, respectively) while the male blackbird was chasing another over a period of about 2 wk in August 1980 (Fig. 1; female cowbird from his territory. Male Yellow­ see also Appendix Din Manolis 1982). These two hooded Blackbirds, which were highly aggressive females were almost certainlyin breeding condition, to female cowbird models in experimental tests of as one appeared to have an egg in the oviduct nest defense, were also aggressive to real cow­ when banded and they weighed 38 and 39 g, re­ birds, especially females (Cruz et al. 1985, Cruz et aL spectively, similar to the masses {38.2 and 39 g) of 1990). two females collected at the UWI Farm with en­ Intrusions by cowbirds into territories of Red­ larged ovaries and eggs in their oviducts. Thirteen breasted Blackbirds exhibited a somewhat similar collected females lacking developed ovaries pattem (Table 2). It was difficult to determine weighed 32.32 (SD = 1.75 g). whether cowbirds were feeding, looki11g for nests, In spring 198I, when pairing at the JS Farm was or both, when in pastures where the blackbirds less frequently observed (Table I), no marked birds were nesting. The intrusions listed in Table 2 were were observed to form temporally stable pairs. Fe­ so classified because they elicited aggressive re­ male YR was seen being guarded and followed by sponses from male Red-breasted Blackbirds. male ORYR on 8 April 1981, but subsequent sigllt­ Pairs of cowbirds were frequently observed in ings of her being followed by males involved dif­ House Wren territories (Table 2). Both male and ferent birds (although in some cases the male could female cowbirds were often observed walking and not be accurately identified). Male GRYL, seen peering about under the eaves of buildings at all most frequently at the farm in I 981, appeared to rural sites. At Teny Hill, cowbirds frequently were have adopted a strategy of courting any female and seen probing with their beaks at the bases of epi­ aggressively displaying to any male that visited the phytes on large saman and other trees (52% of 25 farmyard during the spring of I 981. Male ORYR observations of apparent foraging behaviour). was last seen on 10 Aprill981, after which male House Wrens frequently, and other birds occasion­ GRYL was seen following female YR on 12 and 29 ally, construct nests in such sites. House Wrens April and courting her on 10 May. Other banded responded aggressively in only one of 13 (7.6%) birds were seen less frequently and exhibited no situations where cowbirds were observed near fixed patterns of behaviour. wren nests or following and observing nesting 160 MANOLIS AND CRUZ

8-IV day-month * mist-net location .... 0 OR-OROL pair .... building y YR-ORYR pair road

! N

...... 0 10 ------...... 1--t m 4 ...• ...... ·::-~ ~~·*·:· 0 18-XIII ... :.:::. ·-::··· ~ 0 8-XIII 1111111111,. •::••: •• •:• 1:;~:;::::::::::::::::::::::::::::::::::::::::~~- '~"i,.-:;::::::::::::::::~~" ~~~•..•::• ~:~:·.. ·::::· ::::Y 8-IVtllt--- ',., ~~ .... ·~ .. , ::::•••• •••• :::::••••• -.,.. Ill 0 18 •XIII ...... :::: ..... ' ...... !II ...... :::::::::::::::::::::::::: ...... JS FARM ...... :::: ......

FTG. l. Sightings of colour-marked pairs of Shiny Cowbirds (Molothrus bonariensis) at the JS Farm, Trinid ad, in August 1980 and April 1981. Shiny Cowbird Mating Systems 161

TABLE 2. Observations of Shiny Cowbirds (Molothrus bonariensis) in territories and near nests of potential hosts in Trinidad and Tobago.

Cowbird GrouE Size and Com2osition ~2 ~ ~ Host species ~ld' d'/~ 1 'i' ~2 'i' 'i' +~ld' n House Wren 5 7 13 Troglodytes aedon Ye11ow-hooded Blackbird 2 2 29 5 3 41 Agelaius icterocephalus Red-breasted Blackbird 2 3 3 9 Leistes militaris Other potential hosts• 2 4 •Bare-eyed Thrush (Turdus nudigenis), Tropical Mockingbird (Minms gilvus), and Blue-gray Tanager (Thraupis episcopus) wrens. These observations agreed with low levels The copulation at Malabar Farm occurred on 2 of aggression exhibited by wrens to cowbird May 1981 , during a period when many Red-breast­ models (Manolis 1982). ed Blackbirds were nesting 011 the site and large Two observations were made of potential llllmbers of cowbirds were present. The two cow­ hosts responding to the presence of a male cow­ birds copulated in a tree on the edge of a large pas­ bird, one of whicl1 was accompanying a female, ture and then parted company, the female to forage near nests at Terry Hill. On l June 1980, a Bare­ in the pasture with two other females. eyed Thrush (Turdus nudigenis) was seen calling Other observations suggesting promiscuity in­ and flicking its wings and tail while oriented to­ clude: three sightings (one at the PMH site and two wards a male cowbird perched 6 m fi·om the at the UWI Farm) of male cowbirds courting juve­ thrush's nest. On 2 June 1980, a Tropical Mocking­ nile cowbirds, one of which was still being fed by bird (Mimus gilvus) was seen chasing a pair of a Red-breasted Blackbird; and two instances (both cowbirds from branch to branch within a tree 5 m at the PMH site) of a female being courted by two from its nest. A Bare-eyed Thrush, presumably males in rapid sequence. associated with an active nest 15 m away, attempt­ ed to displace the female cowbird. She responded DISCUSSION by gaping at the thrush, which retreated and then flew at the male cowbird, displacing it and attacking Although based on a small sample size of col­ it in midair. The cowbird pair eventually flew off. our-banded birds, observations at the JS Farm doc­ Cowbird mating behaviour.-Five attempted ument at least short-term pai1ing at this site in fall copulations were observed at the PMH site and 1980. Breeding activity by potential hosts was con­ one was observed at Malabar Farm. All were sug­ siderably less in July-August 1980 than in April­ gestive (but not conclusive) of promiscuous mat­ May 1981, and fewer cowbirds at this site exhibited ings. After at least two of the five copulations ob­ breeding behaviour in the former period. Greater served at the PMH site the birds involved departed local densities of breeding hosts in the spring (e.g., in different directions. One of the other attempts Red-breasted Blackbirds at the nearby Malabar was interrupted by a second male cowbird. The Farm) might favour promiscuity and the type of female and interrupting male then joined a group of behaviour exhibited by male GRYL. three other males and one other female, in which In contrast, the behaviour of copulating birds three of the males simultaneously performed court­ at the PMH site suggested cowbirds might be ship displays directed towards one of tl1e females. adopting a promiscuous mating system at Yellow- 162 MANOLIS AND CRUZ headed Blackbird colonies. This is suppot1ed by important to recognise the importance of scale the low percentage of observed cowbird pairi11gs when referring to densities, of both potential hosts and scant observations of cowbird pairs investi­ and cowbirds. High densities over a broad region gating Yellow-hooded Blackbird territmies and may be generated by either clumped or uniform dis­ nests. We did not colour-band cowbirds at the persion patterns. The critical measures of cowbird PMH site and therefore cannot refute the possibil­ density necessary to test these hypotheses are in ity that pair formation occurred there. Indeed, it is specific areas when and where hosts are breeding. possible that some ofthe observations of mixed-sex Our observations (e.g., high frequency of groups of groups at that site (Table 1) involved one or more cowbirds at the PMH site; Fig. 1) and observations pairs with, perhaps, accompanying individuals of of others (Wiley and Wiley 1980) document the either sex. Males typically outnumbered females in continual presence of substantial numbers cow­ these cases (nine of 14 observed groups), however, birds in breeding condition in the immediate vicin­ with two males courting the same female being the ity of Yellow-hooded Blackbird colonies. most frequently observed category (six of 14 Mating systems might be influenced by cow­ groups). These within-group sex ratios and the be­ bird sex ratios if mo11ogamy (as a result of mate haviour observed within these groups (courtship of guarding) was a more favourable strategy for males one female by multi pie males, lack of mate-guarding when they outnumbered females to a significant or mate-following) suggest that stable pairs were extent(Wittenbergerand Tilson 1980, Darley 1982, not usually involved. Teatl1er and Robertson 1986). Yokel (1989), how­ Investigating blackbird tenit01ies in groups of ever, could 11ot find strong support for this hypo­ two or more females (or males and females) seems thesis in studies of Br0W11-headed Cowbird mating odd behaviour on the part of female cowbirds if behaviour, and Mason's (1987) observations (lack they compete for host nests to parasitize. However, of any pattern of association between the sexes in aggressive territorial defense by male blackbirds, a population of colour-banded birds) suggested particularly in dense colonies containing many promiscuous breeding by Shiny Cowbirds despite nests at similar stages in the nesting cycle, is prob­ a nearly 1: 1 sex ratio. Sex ratios in both Brown­ ably of much greater importance in limiting the headed and Shiny Cowbirds are generally reported number of appropriate egg-laying opportunities for to be male-biased, though the bias is occasionally cowbirds (e.g., see Wiley a11d Wiley 1980) than is slight (Mason 1987, Yokel1989, Ortega 1998). There the absolute number of nests available. Female are major problems in determining accurate sex cowbirds might offset host aggression by timing ratios of breeding cowbirds. Even results from trap­ nest visits to coincide with those of other females, ping data may be biased by behavioural differences using the latter as decoys (Cruz et al. 1990). between the sexes (Ot1ega 1998). Seemingly male­ Elliott (1980) offered the hypothesis that, in the biased sex ratios based on trapping data from feed­ Brown-headed Cowbird, promiscuity was associ­ ing sites at the JS Farm (14 males: 8 females) and ated with open habitats and monogamy with wood­ the UWI Farm (22 males : 16 females) may result ed areas. On the surface, our observatio11s tend to from sexual differences in dispersion. Some studies support his ideas. However, Elliott (1980) based his (Wiley 1980, Rothstein et al. 1984) have indicated hypothesis on the assumption that host densities that male cowbirds are wide-ranging in their visits are lower in open habitats, which is not the case in to feeding sites. If male cowbirds visit a greater Trindad and Tobago. Yokel (1989) suggested that number of feeding stations and wander over larger mating systems in this species were related to cow­ ranges than females, the observed pattern of more bird densities (noting that E11iott's study site was in males being trapped but fewer being resighted a region known for high cowbird densities), and could be generated even with a I: 1 sex ratio. Elliott that promiscuity resulted in areas of high cowbird (1980) offered this explanation for a similar discrep­ densities because males could not adequately de­ ancy in trapping and observation data for the fend, attend to, or demonstrate dominance qualities BroWJ1-headed Cowbird in his study. to females in order to maintain a pair bond. It is The fact that both male and female Shiny Cow- Shiny Cowbird Mating Systems 163 birds, alone and in pairs, were frequently observed females, and the relationship between this behav­ at Terry Hlil searching sites (eaves of buildings, iour and monogamous mating behaviour by the epiphytes, etc.) where House Wrens and other po­ cowbird in reference to specific hosts. Differences tential hosts often nest suggests that female cow­ in size (Strausberger 1998) and aggressiveness of birds might accept mate-guarding by males if males host nest defense, nest site type, and nest dis­ helped find nests or flushed out nesting birds while persion in different areas (e.g., see Wiley 1988) are foraging. Such behaviour could account for all factors that may influence nest-searching be­ Young's (1929:256) statement that "the male does haviour. most of the work of prospecting for nests, and 1 have often watched them examining wren' s nest in ACKNOWLEDGMENTS houses." Kattan (1997) recently presented data on Shiny Cowbird visits to House Wren nests in Co­ Field assistance was provided in Trinidad and lombia that are similar to ours. Most female cow­ Tobago by A. Manolis, B. Mohan, S. Ramdeen, and birds visiting nests in Kattan's (1997) study did so G. Ramdeen. The Forestry Division of the Trinidad as single females rather than in groups of two or attd Tobago Ministry of Agriculture supplied the more females, but were accompanied by males on necessary permits and support for our research. many of these visits. Wiley (1988) observed female Drs. C. D. Adams, M. Alkins-Koo, J. Kenny and Shiny Cowbirds parasitising an array of hosts in other members of the staff a11d faculty of the De­ rural Puerto Rico using both active searching and pattment of Zoology and the Experimental Farm of nest-flushing behaviour, often accompanied by a the University of the West Indies provided wel­ male and/or one-two females. However, in a study comed access to sites and facilities. The Seeyave of Shitty Cowbird parasitism of the Stripe-backed family and Dr. W. Hoyt graciously allowed us to Wren (Campylorhynchus nuchalis) in Venezuela, study cowbirds on their propetiy. P. Mason and, of Piper (1994) found that male as well as female course, R. ffrench, were of considerable inspiration cowbirds frequently ventured close to wren nests in discussion of the ideas presented herein. R. (23% of all cowbirds chased by wrens were males), Payne, C. Starr, J. Wiley and an auonymous re­ but males rarely followed females to nests. He viewer provided constructive comments on the hypothesized that males might visit host nests manuscript. Our research in Trinidad and Tobago alone in order to ( l) find females in breeding con­ was funded in part by: The New York Zoological dition or (2) synchronise their breeding activity Society, the Frank M. Chapman Fund oftlte Ameri­ with tl1at of their mates (suggesting monogamous can Museum of Natural History, the Walker Van paiting). Riper Fund of the University of Colorado Museum, Our observations, though limited in scope, the Graduate School of the University of Colorado, offer some support for the hypothesis that the the Alexander Bache Fund of the National Acad­ Shiny Cowbird tends to be promiscuous where emy of Sciences, and National Science Foundation host (and cowbird) densities are high and extremely Grant #811-2194. localised (e.g., at Yellow-headed Blackbird breeding colonies at the PMH site), and that they may form LITERATURE CITED stable pair bonds where host distribution is less clumped in space aJtd time (e.g., at Terry Hill and ANKJ'IEY, C. D., AND D. M. SCOTT. 1982. On the similar habitats around the JS Fatm, at least in some mating system of Brown-headed Cowbirds. seasons). They also fit the idea that cowbird mating Wilson Bull. 94:260-268. strategies are quite flexible and that some cowbirds CRONIN , E. W. , AND P. W. SHERMAN. 1977. A may follow different strategies in the same area resource-based mating system: the Orange­ depending on the availability and dispersion of rumped Honeyguide, Indicator xanthonotus. various host species' nests. Further research is Living Bird 15 :5-32. obviously needed to clarify tl1e reasons male Shiny CRUZ, A ., T. D. MANOLIS, AND R. W. ANDREWS. Cowbirds may search for nests, with and without 1990. Reproductive interactions of the Shiny 164 MANOLIS AND CRUZ

Cowbird Molothrus bonariensis and the Yel­ in Trinidad and Tobago. Unpubl. Ph. D. diss., low-hooded Blackbird Agelaius icteroceph­ Univ. Colorado, Boulder. alus in Trinidad. Ibis 132:436-444. MASON, P. 1980. Ecological and evolutionary CRUZ, A. T. MANOLIS, AND J. W. WlLEY. 1985. The aspects of host selection in cowbirds. Unpubl. Shiny Cowbird: a brood parasite expanding Ph . D. diss. , Univ. Texas, Austin . its range in the Cmibbean region. Omithol. MASON, P. 1987. Pair formation in cowbirds: evi­ Monogr. 36:607-620. dence found for Screaming but not Shiny Cow­ CRUZ, A., W. POST, J. W. WILEY, C. P. ORTEGA, T. birds. Condor 89:349-356. K. NAKAM URA, AND J. W. PRATHER. 1998. ORTEGA, C. P. 1998. Cowbirds and other brood Potential impacts of cowbird range expansion parasites. University of Arizona Press, Tuc­ in Florida. Pp. 313-338 in Parasitic birds and son, AZ. 371 pp. their hosts-studies in coevolution {S. I. Roth­ PAYNE, R. B. 1973. The breeding season of a par­ stein and S. K. Robinson, eds.), Oxford Uni­ asitic bird, the Brown-headed Cowbird, in Cal­ versity Press, Oxford. ifomia. Condor 75:80-99. DARLEY, J. A. 1978. Pairing in captive Brown­ PIPER, W. H. I 994. Courtship, copulation, nesting headed Cowbirds (Molothrus ater). Can. J. behavior and brood parasitism in the Vene­ Zoo!. 56:2249-2252. zuelan Stripe-backed Wren. Condor96:654-671 . DARLEY,J.A. 1982. Tenitoriality and mating behav­ ROTHSTEIN, S. I., J. VERNER, AND E. STEVENS . 1984. ior of the male Brown-headed Cowbird. Condor Radio-tracking confirms a unique diurnal 84:15-21. pattem of spatial occurrence in the parasitic DUFTY, A.M., JR. 1982. Movements and activities Brown-headed Cowbird. Ecology 65:77-88. of radio-tracked Brown-headed Cowbirds. Auk ROTHSTEIN, S. I., D. A. YOKEL, AND R. C. FLEISCHER. 99 :316-327. 1986. Social dominance, mating and spacing ELLIOTT, P. F. 1980. Evolution of promiscuity in the systems, female fecundity, and vocal dialects Brown-headed Cowbird. Condor 82: 138-141. in captive and free-ranging Brown-headed FFRENCH, R. P. 1991. A guide to the birds of Trini­ Cowbirds. Pp. 127-I 85 in Current ornithology. dad and Tobago. 2nd ed. Comell University Vol. 3. (R. F. Johnston, ed.). Plenum Press, NY. Press, Ithaca, NY. 426 pp. SNOW, D., AND B. K. SNOW. 1964. Breeding seasons FRIEDMANN, H. 1929. The cowbirds, a study in the and annual cycles ofTrinidad land-birds. Zo­ biology of social parasitism. Charles C. ologica 49:1-39. TI10mas, Springfield, IL. 421 pp. STRAUSBERGER, B. M. 1998. Evident nest searching FRIEDMANN, H., L. F. KIFF, AND S. I. ROTHSTEIN. behavior of female Brown-headed Cowbirds 1977. A further contribution to lmowledge of while attended by males. Wilson Bull.llO: 133- host relations of the cowbirds. Smithson. 136. Contrib. Zoo!. 235:1-75. TEATHER, K. L., AND R. J. ROBERTSON . 1986. Pair GOCHFELD, M. 1977. Social systems and possible bonds and factors influencing the diversity of lek behavior in Brown-headed Cowbirds (Mo­ mating systems i11 Brown-headed Cowbirds. lothrus ater). Abstracts, American Omithithol­ Condor 88 :63-69. ogists' Union Annual Meeting, Berkeley, CA. WILEY, J. W. 1980. Development of control meth­ HAVERSCHMIDT, F. 1968. Birds of Surinam. Oliver ods for the Glossy Cowbird. U. S. Forest and Boyd, Edinburgh. 445 pp. Service Project Repmi. KATTAN , G. 1997. Shiny Cowbirds follow the WILEY, J. W. 1988. Host selection by the Shiny "shotgun" strategy of brood parasitism. Anim. Cowbird. Condor 90:289-303. Behav. 53 :647-654. WILEY, R. H., AND M. S. WILEY. 1980. Spacing and LASKEY,A. R. 1950. Cowbird behavior. Wilson Bull. timing in the nesting ecology of a tropical 62:157-174. blackbird: comparison of populations in dif­ MANOLIS, T. D. 1982. Host relationships and ferent environments. Ecol. Monogr. 50:153-178. reproductive strategies of the Shiny Cowbird W!TTENBERGER, J. F., AND R. L. TILSON . 1980. The Shiny Cowbird Mating Systems 165

evolution of monogamy: hypotheses and evi­ mating behavior of Brown-headed Cowbirds: dence. Annu. Rev. Ecol. Syst. 11:197-232. their relation to population densities and sex YOKEL, D. A. 1986. Monogamy and brood para­ ratios. Condor 91 :43-51 . sitism: an m1likely pair. Anim. Behav. 34: 1348- YOUNG, C. G. 1929. A contribution to the ornithol­ 1358. ogy of the coastland of British Guiana: part III. YOKEL, D. A. 1989. Intrasexual aggression and the Ibis ser. 12,5:221-261. Pp. 166-179 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies , St. Augustine, Occ. Pap. II , 2002.

BREEDING BIOLOGY OF THE BLACK-THROATED MANGO (ANTHRACOTHORAX NIGRICOLLIS)

VrcToR c. QUESNEL P. 0. Box 47, Port of Spain, Trinidad and Tobago

ABSTRACT.-During a 9 yrperiod (1985-1993), the Black-throated Mango (Anthraco­ thorax nigricollis) built 28 nests in three open-sided greenhouses (GHs) at Talparo, Trinidad. One GH was particularly attractive, acquiring 23 nests; this was attributed to its provision of 140 sites with excellent support for the nests and a close cover overhead. Building material was partly identified and building methods are described. Nine nests were used more than once: four twice, four three times and one four times. Eighty-one eggs were laid, usually early in the morning. Five single eggs were lost before the second was laid. Nestlings hatched mostly in the morning after an incubation period of 16-18 days (x = 17.2 for first egg; x = 16.5 for second egg), but a few hatched in the afternoon. Fledging took 21-26 days ( x = 22.6 for first nestling; x = 22.7 for second nestling). The female brooded the nestlings for 8-12 days. Fledging (first flight) of the nesthngs was usually early in the morning. Reproductive success (percent of eggs producing fully fledged young) was 56.5%. Some causes of egg or nestling loss were identified.

RESUMEN.-Durante un periodo de 9 afios (1985-1993), el Mango Pechinegro (An ­ thracothorax nigricollis) construy6 28 nidos en tres invemaderos con paredes abiertas en Ta1paro, Trinidad. Uno de los invernaderos fue especialmente atractivo, adquiriendo 23 nidos; esto fue atribuido a que provefa 140 sitios con excelente soporte para los nidos y a poca distancia del techo. El material de construcci6n fue parcialmente identificado y se describen los metodos de construcci6n. Nueve nidos fueron usados mas de una vez, cuatro dos veces, cuatro tres veces, y uno cuatro veces. Se pusieron 81 huevos, principalmente temprano en Ia manana. Cinco huevos fueron perdidos antes de que el segundo huevo fuera puesto. La mayoria de los pichones exclosionaron en Ia manana despues de un periodo de incubaci6n de 16-18 dias (x = 17,2 para el primer huevo; x = 16,5 para el segundo huevo), pero algunos eclosionaron en la tarde. Los pichones salieron del nido despues de 21-26 dias (x = 22,6 para el plimer pi chon, x = 22,7 para el segundo pich6n). La hembra atendi6 a los pichones entre 8-12 dias. EI p1imer vuelo de los pichones por lo general ocurri6 temprano en Ia mafiana. El exito de reproducci6n (porcentaje de huevos que produjeron pichones que salieron del nido) fue 56,5%. Se identificaron algunas causas de Ia perdida de huevos y pichones.

KEY WORDS.- Anthracothorax nigricollis, Black-throated Mango, breeding biol­ ogy, breeding season, egg laying, fledging, incubation, nest construction, nest sites, reproductive success

166 Breeding Biology ofthe Black-throated Mango 167

The Black-throated Mango (Anthracothorax length of each bay and from which strings hung nigricollis), a relatively large species of humming­ down for tying to the plants and supporting them. bird, is common in Trinidad and Tobago during the In each odd-numbered bay there were four chan­ breeding season from December to July, but is nels and in each even-numbered bay three, with scarce from August to November, suggesting that walkways between the channels about 93 em wide it may be migratory (ffrench 1991 ). A few previous in the odd-numbered bays and 80 em wide in the observations of its breeding biology in Trinidad even-numbered bays. This arrangement meant that have been published. Belcher and Smooker (1936) in the odd-numbered bays, extra L-shaped brackets described one nest and measured one egg. Snow had to be fitted to take the crop-support wires over and Snow ( 1964) determined the annual breeding the outer rows of plants near the uprights . In these cycle, and noted the reuse of nests and the inter­ bays, the inner two pairs of wires were supported vals between occupations. Herklots (1961) and by the stays ~ 92 em from the junction of stay and ffrench (1991) summarised their own observations, arch. In the even-numbered bays, three pairs of and ffrench (1991) incorporated unpublished crop-support wires ran the length of each bay and observations ofD. W. Snow. the nearest wire to the junction of stay and arch The greenhouses (GHs) at my home in Talparo, was ~ 18 em; this turned out to be a crucial differ­ Trinidad, were frequently used as nesting sites by ence. mangoes. One objective of this paper is to deter­ Bays 1 and 11, which were the outermost bays, mine why these artificial structures were so attrac­ differed from the other bays in having only one tive as nesting sites. Because nests in the GHs upright; in them the arch came down to the ground were easy to observe, a second objective is to on the outside in a smooth curve. The GH was cov­ describe the breeding biology of the Black-throated ered with plastic, which on the outer bays did not Mango. come down lower than about 1 m from the ground so that the GH was open on a11 four sides. STUDY SITE AND METHODS GH3 was larger than GH2 in overall area and in the size of each of its ten bays. The supports for Observations of nesting Black-throated Man­ the crop wires were larger than those of GH2, dif­ oes were made near Talparo, Trinidad, from 1985- ferent in design and flat on top. GH4 had only 1993. Because the birds 11ested in GHs, I will seven hoops covering an area of 100 m2 and stays describe these structures in detail. 1l1ere were three 4.0 em in diameter at about 2.1 m above ground large GHs and a small one. GHl was of a different level. It, too, was open all round. design from the others and attracted only two I observed the birds opportunistically. To nests. The others were all of a similar design. GH2 record the sequence of movements used in building attracted 23 nests, GH3 three nests and GH4 (the a nest, I spoke into a tape recorder and later tran­ small one) two nests. scribed the material. Having found a nest at an In GH2, tl1e unit of constmction was a stmc­ early stage, I would record the days on which the ture like a croquet hoop of zinc-coated iron pipe. To eggs were laid and then wait 15 days to begin ob­ each bay there were 16 hoops, 1.8 m apart. The servation again; I did not mark the eggs. Similarly, hoops of adjacent bays. were bolted together and after the nestlings hatched I would wait 3 wk before the peaks of the hoops in each bay were joined by returning to the nest to record the fledging (first pipes running the length of the bay. Between each flight) of the nestlings. Later I visited the nests pair of adjacent bays a gutter ran the length of the more often, but my observations were often incom­ bay and served to conduct rainwater from the plete. 2 plastic roof. GH2 had 11 bays occupying 1350 m • For analysis, nests in each GH were listed Each hoop consisted of two uprights, a curved chronologically and numbered. Nests in GH2 were arch connecting them and a stay, which was a numbered from I to 23, those in GH3 from 24 to 26, straight piece of pipe beneath the arch. 1l1is served and those in GH4, 27 and 28. Nine nests were used as a support for the crop wires, which ran the more than once. Each of these has a decimal point 168 QUESNEL and a numeral added to the nest number. Thus, 2.1 webs in the angles of window panes on each of 4 indicates the first use of nest 2, 2.3 indicates its days from 6-9 January 1984, and another collect third use, etc. Several observations came from an them from the ground where they may have sur­ aberrant female in male plumage (Quesnel I 995) rounded the retreats of trapdoor spiders or other whose nests were 8, 13-16, 18 and 27. All dates are ground-dwelling spiders. Spider web was not col­ given in the form of day/rna/yr. lected one strand at a time, but in sheets where they occurred naturally as such. RESULTS I cannot be certain that I have ever seen a nest constructed from the moment the first material is Nest site selection.-The distribution of nests brought to the site, but a sign that a site is being within GH2 was as follows: bay 2, five; bay 3, one; prospected is a characteristic little dance that the bay 4, three; bay 6, four; bay 8, two; bay 1 0, six; female performs. She stands upright at the chosen and bay 11, one (the location of the first nest spot, flutters her wings and swivels around her discovered in June 1985 was not recorded). Odd­ vertical axis from side to side. numbered bays together had two nests; even-num­ Because neither lichen nor plant down would bered bays together had 20. The nests were built stick easily to the stay, I assume that either cobweb on either the stays or the L-shaped brackets. The or a salivary secretion is first put in place (the latter exact location was recorded in ten of these 22 seems more likely). On 09/01 /90, after I had exam­ nests; nine were placed 8-10 em from the junction ined a spot that I thought had been chosen by a of stay and arch and one was placed on an L­ female but found nothing but a little roughness, a shaped bracket 22 em from its junction with the female came to the spot twice with nothing in her uptight. bill that J could see. Each time she opened her bill, Nest constrnction.-Nest materials included shuddered and moved it back and forth as though plant fibres, lichens, cobwebs and possibly saliva regurgitating something on the stay. She then re­ or regurgitated nectar. I have seen the Black-throat­ peatedly flew off and retumed with fluff and stuck ed Mango collect two lcinds of fibres: the hairs that it in place. form a pappus on the seeds of Emilia sonchifolia The following 2 days I watched the female (family Asteraceae) and the hairs on the seeds of build the nest. In summary, she sat in the nest fac­ an unidentified grass (family Poaceae). The former ing either east or west across the stay (never along is a weed about 0.5 m tall, bearing small flower it), moved her head in a semicircle (sometimes more) heads with about 58 flowers per head. When the around the nest seemingly regurgitating saliva on seeds develop, each seed has a pappus of hairs 6-7 it, flew off, retumed with fluff, put it in place and mm long, forming a more or less globular tuft of worked it around her body with her bill, shuddering fluff ±2 em in diameter. As the female harvests this and seemingly regurgitating more saliva. She would tuft, the seeds come with the hairs and are incor­ also regurgitate on the sides of the stay and even porated into the nest. I do not know if the seeds under it as far as she could reach while remaining accompanied the hairs that the female harvested seated. She shaped the nest around her body by from the grass. 1 retrieved the fallen nest, picked the spreading and sticking in place successive masses seeds off, germinated them and grew five plants to of cobweb and plant down. My observations were the flowering stage. They were all E. sonchifolia. made from 1400-1630, but the female built in the I once saw a female harvest lichens from a morning as well. black fiddlewood tree, Vitex divaricata (family Ver­ The mean duration of nest construction from benaceae). Lichens on all the nests l have found when the merest wisp of fluff was in place to the were thin, irregular flakes 2-3 mm across; they were laying of the first egg was 7.0 days (range = 4-11 incorporated into tl1e nest at a very early stage. days, n = 7). I have never seen the Black-throated Mango Egg laying.-Table 1 lists 16 instances where (or any other hummingbird) collect material fi·om the the date of laying was certain and the time of day at orb webs of spiders, but I did see one collect cob- which the egg was discovered. All eggs were laid Breeding Biology of th e Black-throated Mango 169

TABLE 1. Time when eggs were discovered in nest. TABLE 2. Interval between laying of eggs within a 11est. Nest Egg Date Time Sunrise 7.2 2 15/02/89" 0900 0626 Date of E~~ La~n~ 9. 1 2 19/01 /90' 0950 0630 Nest no. Egg 1 Egg2 9.2 2 15/03 /90b 1000 0613 2.1 28/ l/86d 30/1/86 10. 1 2 26102190. 0845 0622 10.2 05/5/90" 09/5/90b II ]J/Ol/9] c 0645-0915 0628 13 13/2/91 a 15/2/91 12.3 24/06/91d 0900 0545 14 04/3/91 a 06/3/91 c 13 13/02/91 e 0800 0627 15 27/4/91d 30/4/91 c 2 15/02/91 c 0700-0830 0626 17.2 28/2/9lb Ol/3/92c 14 2 06/03/91 b 0830 0617 27.2 20/3/90d 22/3/90c 15 2 30/04/91 b 0930 0548 27.3 12/5/90b 14/5/90c 16 16/05/91 f 0900 0543 •no egg present the day before 2 18/05/91 f 0930 0543 bno observation the day before 17.1 I 09/01 /92d 0730 0627 conly one egg present the day before I8 04/0l /92d 1030 0626 cl no female present the night before 27.2 20/03/90d 0715 0611 2 22/03/90c 0616 0610 "first egg 2 days before For two nests in Table 3 (7 .2 and 12.1), the sec­ bone egg in nest the day before ond egg followed a day after the discovery of the

TABLE 3. Time when nestlings hatched. discovery (1 030 and 11 00) because egg shell frag­ ments were present in the nest then. Of the four Nest Nestling Date Time remaining nestlings, one (in nest 4) hatched later 4 2 08/02/87 0930-1 730 than 0930, two (in nests 8 and 9.2) hatched near 7.2 02/03/89 0930 midday as indicated by egg shell fragments in the 2 03/03 /89 0900 nests when observed at 1145 and 1200, and the last 7.3 1 24/04/89 1100 (in nest I 0.1) hatched near 1700 as indicated by egg 7.4 1 15/06/89 0800 shell fragments in the nest at the time. 2 16/06/89 0845 Table 4 gives the more reliable results relating 8 1 09/06/89 l200a to incubation and fledging. ln nests 7.3, 7.4, 10.1, 9.2 2 3 1/03/90 1145" 12.2 and 12.3, tl1e eggs of each pair hatched 1 day 10.1 1 14/03/90 0800-1700" apart. In nests 12.1 and 18, the eggs of each pair 12.1 1 11/02/91 0700-0815" hatched 2 days apati. In nests 2.3, 7.2 and 9.1, the 2 13/02/91 0800 date of hatching of the first nestling was uncertain 12.2 1 26/04/91 0645 because there was no observation on the day pre­ 2 27/04/91 0700 ceding its discovery. 12.3 1 12/07/91 0730 The eggs in nest 16 seemed to have hatched 3 2 13/07/91 0930 days apmi because there were egg shell fragments 16 2 03/06/91 0900 in the nest when I discovered the first nestling on 18.1 1 21 /01 /92 1030" 31 /05/91 and tl1ere were two nestlings when I exam­ 27.2 2 07/04/90 0930" ined the nest on 03 /06/91, having found only one 27.3 29/05/90 0930" the day before. However, 1 examined the nest at 28.1 ?1b 18/03 /92 11 00" 1015 on 02/06/91 ; thus, the second nestling may 28.2 1 07/05/92 0900 have hatched later that day. "egg shell present at time of observation In nest 17.1 , there were two eggs in the bonly one nestling hatched; which one is unknown morning of26/01/92 and two nestlings at 1400 on 27/01/92, but the first nestling probably hatched on 26/01 /92 before 1800, when I checked the nest for In the remaining nests of Table 2 ( 10.2 and 15) hatching at1d found the female sitting. I touched the eggs were clearly laid more than 2 days apart. her gently to flush her but she refused to leave and For nest 15 the interval is clearly 3 days ; for nest trembled violently. Presumably a nestling hatched 10.2 the interval is uncertain. The first egg was laid after I had examined the nest in the morning, so this on 05/05/90, and the second egg had not been laid pair of nestlings probably hatched a day apart. when the nest was checked at some unrecorded In one other instance of nestlings seemingly time on 07/05/90. The nest was not checked on hatching on the same day (nest 4, Table 3), the one 08/05/90, and on 09/05/90 there were two eggs. nestling in the nest at 0930 had probably hatched Presumably the second egg was laid on 08/05/90, 3 the day before when there had been no examina­ days after the first. tion, and the second nestling at 1730 on the same Hatching of eggs.- Table 3 lists 21 instances day had probably hatched between 0930- 1730. where the date of hatching and the time of discov­ Pooling the results of groups I and 2 where the ery of the hatched nestlings are known with cer­ data are firm and that of nest 17.1 where they are tainty. Hatching usually took place in the morning highly probable, I conclude that for eggs laid 2 before 0930, but occasionally occurred near mid­ days apart the eggs usually (75%) hatch I day day or in the afternoon. At least 14 (64%) of the apart and occasionally (25%) 2 days apart. Nest­ nestlings hatched before 0930 and 17 (81 %) before lings probably never hatch on the same day and 11 00; of the extra four, two may have hatched be­ probably hatch 3 days apart only if the eggs are fore 0930, but the other two (in nests 18 .1 and 28.1) laid 3 days apart. would have hatched close to the recorded times of Incubation period.-During the nest construe- Breeding Biology of th e Black-throated Mango 171

TABLE 4. Recorded dates for laying, hatching and fledging, and duration (days) of incubation and fledging. Where data are incomplete, favoured interpretations are underlined. 'Chick'= 'nestling'.

Date of la~n~ Date ofhatchin~ Incubation Date of fled gin~ Fledging Eeriod Nest Eg~ 1 Eg~2 Chick 1 Chick 2 Eg~ 1 Egg 2 Chick 1 Chick2 Chick 1 Chick 2 2.3 05/05/86" 07/05/86 22/05/86" 23/05/86 16,11 16 14/06/86b 15/06/86b 23, 24 23 3 22/05/86° 13/06/86d 22 7.2 14/02/89e 15/02/89 02/03/89" 03/03/89 16, 11 16 26/03/89af 28/03/89df 24, 25 25 7.3 24/04/89g 25/04/89 16/05/89bf 17/05/89 22 22 7.4 29/05/89. 30/05/89 15/06/89£ 16/06/89 17, 1.§_ 17 06/07 /89b 07/07/89 21 21 9.1 17/0l/90h 19/01 /901 03/02/90" 04/02/90 16, 17 I6 26/02/90b 28/02/90df 23, 24 24 9.2 31 /03/90c 23/04/90df 23 I 0.1 25/02/90. 26/02/90 14/03/90° 15/03 /90 17,1.§_ 17 06/04/90b 07/ 04/90f 23 23 12.1 26/0 l/91 e 27/01/9 I I l/02/91 c 13/02/91 i 17 17 06/03/91 bf 07/03/91 f 23 22 12 .2 09/04/91 k 11 /04/91 a 26/04/91 g 27/04/91 17 16 18/05/91 bf 23/05/91 df 22 26 12.3 24/06/91" 26/06/91 3 12/07/9]8 13/07/91 18 17 1 1 16 16/05/91" 18/05/91" 31 /05/9 1c 03/06/91 j 15, .!& 16 22/06/91 b 23/06/91 22 20,l.l 17.1 09/01 /92k 11 /0l/92" 27/01 /921 27/01192 11, 18 16 17 /02/92b 18/02/92 21,22 22 18 04/01/ 92k 06/0 I /92" 21/0 l /92" 23/0 I J92i 17 17 13/02/92b 15/02/92. 23 22, 23 28 .2 07/05/92g[ 29/05/92j 22 "no observation the day before htwo nestlings present the day before cegg shell present at observation; indicates recent hatching done nestling present the day before

TABLE 5. Parental night-time brooding period (days from hatching to last day female was seen on nest).

Nest- I st nestling Female last Female Days Fledging Nest lings hatched seen on nest off nest brooded Eeriod 9.1 2 03/2/90 ll /2/90 12/4/90 8 23,24 10.1 2 14/3/90 23/3/90 24/3/90 10 23,23 12.1 2 11/2/91 20/2/91 21/2/91 10 23,22 12.2 2 26/4/91 04/5/91 0515191 9 22,26 16 2 31 /5/91 I 0/6/91 11/6/91 11 22,21 17.1 2 26/1/92 04/2/92 0512/92 10 22,22 18 2 21 /1192 01/2/92 0212192 12 23, 22 28 .1 1 18/3/92 25/3/92 27/3/92 8,9 20 and 18 days and 17 days for three nests. Less com­ Development and behaviour of nestlings.-1 monly they are the same, 17 days for each in two recorded the time when nestlings first opened their nests and 16 days for each in nest 16 where the eyes . In nests 12.1 and 26, the eyes of the first nest­ data are uncertain. TI1e mean duration (±SD) for all ling were open on day 8 after hatching. In nest 10.1, 22 eggs is 16.8±0.67 days (x = 17.2±0.60 days for the eyes of both nestlings were still closed on day first egg; x = 16.5±0.52 days for second egg). 1 1 after hatching. The fledging period was 23 days Nestling period.-Data for the nestling period, for all these first nestlings. defined as the time between hatching and fledging I recorded whether nestlings were positioned (first flight), are available for only six nests (Table head-to-head or head-to-tail in the nest. I hypoth­ 4). In four nests (7.3, 7.4, 10.1, 12.2) the dates of esised that the nestlings would be head-to-head hatching and first flight are certain; of these, three during the day (for easier feeding) and head-to-tail (7 .3, 7.4 and 10.1) give the same nestling period for during the night (for a neater fit to the nest). How­ both nestlings, although the duration for each 11est ever, a series of observations showed no support is different. In two nests, however, the periods for for this. During the day, the nestlings were head-to­ the two nestlings differed; in nest 12.1 the first head 24 times and head-to-tail 15 times; at night, nestling had the longer period whereas in nest 12.2 they were head-to-head four times and head-to-tail the second nestling had the longer period. Thus, twice Cl = 0.00, df = 1, P = 1.00). nestling periods of the same duration for both Brooding period.-While the nestlings are nestlings seem to be more usual than periods of young the female broods them both day and night, different duration. In nest 3 the dates are certain for but at a certain stage of development she ceases to the second nestling only. brood at night. Observations at 8 nests revealed The remaining nests in Table 4 can be divided that all females brooded for at least 8 days after the into three groups: nests 2.3, 16 and 17 .1 with nest­ first nestling hatched; one stayed as long as 12 lings fledging in successive days; nests 7 .2, 9.1 and days (Table 5). 18 in which the nestllngs flew 2 days apart, and Fledging.-For seven nests 1 recorded when nests 3, 9 and 28.2 in which only one nestling the nestling occupied the nest the day before and hatched. was absent in the morning (Table 6). Six nestlings Assuming the favoured figures for fledging in were seen near the nest after leaving it. Two nest­ Table 4 are correct, nestling periods that are the lings were present at a first visit in the morning but same for both nestlings in a nest slightly outnum­ had fledged by a second visit; one of these fledged ber those that are different 6:5. The mean nestling later than 0940. All but two of the others are known period (±1 SD) for all nestlings was 22.6±1.2 days to have fledged before that time, though one (22.6± 0.8 for first nestling, 22.7±1.5 for second; fledged by 1000. Thus, as with laying and hatching, mode= 22, rang<:= 21-26 days). fledging is usually an early morning event. Breeding Biology of the Black-throated Mango 173

TABLE 6. Time of fledging, when absence of a nest­ cloned if unattended for two successive days. A ling was first discovered or between which it left nest was considered destroyed if it could not be the nest. found. An egg or nestling was considered as lost to a predator if the nest was empty and there was Nest 1st nestling 2nd nestling no sign of egg or nestling on the ground below. In 9.1 0930" three nests (9.2, 28.1, 28.2) there was partial loss in 10.1 1000 0930 3 that one nestling was raised from each and one egg 12 .1 08303 0830" was lost. 1l1e others suffered total loss, both nest­ 12.2 0930" 0820" lings or eggs (n = 10), or the only egg (n = 4). In the 17.1 0900 latter four nests, the loss occurred before the sec­ 18 0940-1530 ond egg was laid: one egg fell or was thrown to the 19 0700-0900 ground, one was presumed eaten and two were in "nestling seen near nest after leaving it abandoned nests. In nest 26, a 19-day-old nestling and an infe11ile egg disappeared simultaneously, suggesting loss to a predator. Reuse of nests.-A nest was used more than The suspected causes of failure of 17 nests once in nine of 28 (32%) nests. Table 7 gives the (Table 8) were attributed to the following factors: intervals between occupations from the vacation of infertility, 9.7%; nest abandonment, 9.7%; egg dis­ the second (or only) nestling to the next laying of lodgement, 3.2%; nest destruction, 9.7%; and pred­ an egg for 13 occupations. The intervals fall into ation, 11 .3%. In three other nesting attempts where two groups, one of 7-13 days (x = 10.9) and the the outcome was probable rather than certain, two other of 25-33 days ( x = 28.6). I twice observed the nestlings fledged from one, one nestling fledged easily recognised aberrant female feed fledglings 12 from one where the other one died at a fairly ad­ and 14 days, respectively, after the second nestling vanced stage (which I removed), and one nestling had left the nest. These times are comparable to the fledged from the only fertile egg. Recalculating first group of times between occupations of the percentages with the inclusion of these figures, egg nest. Thus, the fledglings may be able to feed for success was 57.3%, with loss due to: infertility, themselves independently of their mothers after 2 10.3%; nest abandonment, 8.8%; egg dislodgement, 2.9%; nest destruction, 8.8%; predation, 10.3%; and wk and allow their mothers to start a new brood. death by an unknown agent (pathogen?), 1.5%. Reproductive success.-Of 28 nests the out­ Breeding season.-Acceptably accurate laying come was uncetiain in four; 12 nests produced at dates are available for 76 eggs from December to least one fully fledged young and 12 nests pro­ July (Table 9) . In the third column ofTable 9 are the duced no fully fledged young. Thus, nesting suc­ laying dates of a small set of females who began cess was 50%. The aberrant female in male plumage laying in January and reused their nests at least over 4 yr built seven nests of which three were once. successful (43%). The breeding season comme11ced in December, Counting all the nests in which the outcome which is earlier than reported previously (ffrench was certain, i.e., all those in Table 8 plus those 1991), and extended to July, with little activity in where two nestlings were known to have fledged, June and July. Cyclic laying activity resulted in there were 33 nests in which 62 eggs were laid, four peaks during January, March and May (Table 9). of the nests having only one egg as noted above. From these, 35 fledgings were produced, for an egg DISCUSSION success rate of 56.5%. The aberrant female raised six fledged young from 14 eggs laid (43%). Nest site selection.-In trying to determine Table 8 provides information on 17 nesting what made GH2 so attractive to the species, I con­ attempts in which there was partial or total loss of sidered four features of the favoured nest sites: the eggs or nestlings. A nest was considered aban- height above ground, the diameter of the stay; the 174 QUESNEL

TABLE 7. Interval in days between occupations of served such a nest. the same nest. Having arrived at a conclusion about the im­ portant features of the preferred site, I tried to think

Nest Nest Da~s of a situation in nature that would duplicate it. I 5.1 5.2 11 concluded that a site near the trunk on the petiole 7.1 7.2 11 of a Cecropia peltata (family Cecropiaceae) leaf 7.2 7.3 10 would be close, and began to look for nests on 7.3 7.4 11 Cecropia leaves. In one day I found two nests. 9.1 9.2 13 There was as well one on a Cecropia branch that 9.2 9.3 7 mimicked the GH situation. For purpose of com­ 10.1 10.2 28 parison I measured the width of Cecropia petioles 12.1 12.2 33 taken from unbranched trees which I felled, selec­ 12 .2 12.3 32 tiug 20 leaves that came off the trunk at about a 17.1 17.2 25 right angle. There is a channel in the trunk above a 27.1 27.2 25 leaf node. Measuring from the rim of the channel I 27.2 27.3 12 marked off3, 5 and 10 em distances along the peti­ 28.1 28.2 12 ole and measured the width at these points as care­ fully as possible. For the insertion I used a pair of dividers to span the distance between two tiny presence of the covering on the arch above the downward projections, one on each side of the leaf stay and the colour of the stay. ffrench ( 1991) gives base, on the pale ridge that circles the node. I the preferred height of the nest as 6-15 m and determined mean± 1 SD as follows: insertion, 32.8 Herklots (1961) as 5.5 m. The height of the stay ± 2.0 mm; 3 em, 18.1 ± 1.85 mm; 5 em, 13 .3 ± 1.52 above ground at the four sites where it was meas­ mm; and 10 em, 10.5 ± 0.48 mm. Thus, the petiole ured had a mean of2.5 m (range= 2.44-2.55 m) and provides a wide support near the trunk that nar­ the height ofthe bracket at nest 10 was 1.94 m, both rows to just over 1 em beyond 5 em from the trunk. well below the height at which the species usually The petiole is very firmly attached and provides builds. Thus, height could not have been a power­ support far in excess of the weight of nest and bird. ful attractant. While looking for nests in Cecropia leaves I found The diameter of the stay at the four sites had a nests in other places too: seven nests on Cecropia mean of2.25 em (range=2.2-2.3 em) and the diame­ branches, three in Swamp Immortelle (Erythrina ter ofthe bracket at nest 10 was 2.5 em. Both struc­ glauca; family Papilionaceae), two on a beam in tures provided good support for the nest cup GH1 and one in GH3 beneath a pipe. which was 3.8 em in diameter(ffrench 1991). At the In describing GH2 I pointed out that in the measured sites the plastic roof was 11 .9 em (range even-numbered bays the two outermost crop­ 11.5-12.3 em) above the stay and at nest 10-36 em support wires passed over the stays 18 em or less above the bracket. The closer cover may well be a from the junction of stay and arch, whereas in the factor in the preference for stay over bracket and, odd-numbered bays the wires passed no nearer as well, in the preference for end of the stay over than about 90 em. I suggest that to the bird this is middle. The grey colour of the stay blends well with a crucial difference. The junction of stay and arch the pale colour of the nest and provides camou­ is already an attractive site because the roof comes flage. Thus of the features considered, three seem down near to the stay at this point. In the even­ to be particularly favourable. numbered bays the wire is easily within the field of Young hummingbirds approaching the time of vision as the female prospects the site. To her it fledging exercise frequently by fluttering their may signify added support for the nest. wings (Skutch 1973). A position of the nest close In the greenhouse situation the wire does not against the junction of stay and arch would prevent have to pass over the stay at exactly the distance the young from exercising, and I have never ob- (about 10 em) from the junction of stay and arch Breeding Biology of the Black-throated Mango 175

TABLE 8. Suspected cause to loss of eggs or nestlings in 17 nests suffering total or partial loss. E = egg; N = nestling.

Infer- Aban- Dis- Des- Pred- Nest Eggs tility cloned lodged troyed ation Fledged 5.1 2 2E 5.2 2 2E 8 2 1 E, IN 9.2 2 1 E IN 11 1 E 13 2 2£ 14 2 2£ 15 2 2E 12.3 2 2N 17.2 2 2£ 20 I E 22 1 IE 23 1 1 E 24 2 1 E IN 26 2 1 E IN 28.1 2 1 E IN 28.2 2 IE IN Total 30 6 6 2 6 7 3

where tl1e nest will be located. It is enough for it to sition? I think not. The birds seem to like the cover be close by to suggest 'extra support'. This is provided by the hoop and the plastic of the green­ what, in my view, makes stays of even-numbered house. Though a plastic cover is not available in bays more attractive than those of the odd-num­ nature, the birds evidently build in similar situ­ bered bays. With five even-numbered bays each ations. What is the importance of the cover? Do the with 14 internal hoops and two ends to each stay, birds appreciate it as a protection from rain, from there are 140(14 x 5 x 2) extremelyattractivesitesin sun or from aerial predators? Skutch (1973) records GH2 and another 168 (14 x 6 x 2) sites only slightly that hummingbird mothers will protect their young less desirable. Where in a natural habitat is there an from both rain and sun, so cover for the young area of 1350 m2 with so many desirable sites? But must be important. Since nesting takes place mainly this largesse comes with a price. The regular ar­ in the dry season, rain seldom will be much of a rangement of the sites evidently causes some con­ problem. Regrettably I never tried to see if, in the fusion. The birds sometimes started nests on two event of rain, they would rush back to the nest to nearby sites, eventually settling on one. But on cover nestlings despite the presence of a plastic 21/02/93, I discovered three unfinished ones on cover. each of stays 2, 3 and 4 in Bay 10. On 24 February However, hiding the nest from aerial predators the nests on 2 and 3 had one egg each and this should reduce the loss of nestlings. Several bird situation remained unchanged up to 1 March. species, such as hawks, owls, the Great Kiskadee Seemingly, one female had built all three nests, had (Pitangus sulphuratus; ffrench I 991) and the become confused and eventually abandoned the Smooth-billed Ani (Crotophaga ani; Chrichlow whole project. 1967), are known to take nestlings, and some spe­ Is this 'extra twig' near the junction of stay and cies of bats in Trinidad are known to prey on birds hoop the sole reason for the attraction of this po- (Eisenberg 1989). 176 QUESNEL

TABLE 9. Monthly distribution of eggs by known Little is known about the materials used by laying date. 'Total' refers to all eggs; 'select' refers hummingbirds to make their nests. Skutch (1973) to a selected group of repeat users of nests (see mentioned "softest down from seeds, or hairs from text). furry leaves ... foliaceous lichens, tufts of green moss .. . brown scales from the unrolling fronds of Month Total Select large ferns, fine fibrous rootlets, bast fibres, frag­ December 2 0 ments of grass or leaves, wool, small feathers". January 21 12 However, not one species is named. February 9 The Emilia sonchifolia from which I saw a March 11 7 Black-throated Mango collect seeds is just one of April 11 3 a large number of similar weeds in the family Aster­ May 17 3 aceae that could just as well have provided mate­ June 2 2 rial. E. coccinia has slightly larger flowering heads July 3 0 and might be even more attractive. Vernonia ciner­ ea is somewhat smaller and may be less attractive but is very common and may also be used. Hummingbirds are known to mob hawks and Since the hairs that the hummingbirds seek are owls, and a W11ite-chested Emerald (Amazilia chi­ more strongly attached to the seeds than the seeds onopectus) was once observed giving audible wing are to the receptacle on which they sit, ilie seeds blows to a Great Kiskadee (Skutch 1973).ln light of come with the hairs when col1ected by the hum­ their ferocious reputation, I cannot recall ever hav­ mingbird. They can be collected from the nest and ing been attacked by any Black-throated Mango as grown in order to provide reliable identification and I peered into their nests. Rather the reverse; they doing this would be a comparatively easy way to tolerated my presence, as did the female which re­ learn just what species provide the birds with their fused to vacate her nest even when touched. material. Also, it must be noted that the seeds are in The use of Cecropia for nest sites in Trinidad no way a decoration in the sense tl1at the birds de­ has been reported previously (Belcher and Smooker liberately employ them for camouflage. (1936, Herklots 1961). Judging from the greenhouse The silvery hairs of this weed are just what the situation, Cecropia provides solid support for the bird requires for keeping the nest inconspicuous on nest and the large leaves help conceal the nest from the zinc-coated stays of the greenhouse, but there aerial predators though it is easily seen from below. was the possibility of brown hairs being collected Neither of the two nests that I have seen on Cecro­ (from perhaps Mandevilla hirsuta, family Apo­ pia leaves was touching the trunk where the petiole cynaceae) for the construction of a nest on a brown is broadest and would give the best support. The support such as the stem of a tree with brown bark. reason for this seems to be the need for the young The spider webbing collected from my win­ to exercise their wings often before they attempt to dows comprised the retreats of a tiny spider about fly. T11is need in tum is probably the reason for the 5-6 mm from the tips of the front legs to the tips of 'dance' that the female does when she selects the the hind legs. They lodge in the angle between site. She does this to make sure that there is space pane and frame and cover themselves and their egg enough for the young to flutter their wings when cases with a silken sheet about 1 x 2 em. The the time comes for this. sheets can be easily peeled off and several of them Nest construction.-While constructing the collected on one trip make a convenient bill full. The nest, the females never sat with the long axis of question arises whether the bird ever takes bits their bodies in line with that of the stay but always from much larger retreats such as those of the so­ at 1ight angles to it. I have no notes about how called tarantulas (Tl1erophosids) or the web-spin­ they sit when incubating. Perhaps their behaviour ning insects of the order Embioptera. in this regard is peculiar to the greenhouse situ­ My notes record the incorporation of lichens ation. very early in the construction of a nest when it is Breeding Biology of the Black-throated Mango 177 hardly visible and on what will become the floor of nest overnight". Thus, the behaviour of the female the nest as well as in the wall. Skutch (1973), too, early in incubation determines how far apart the records the presence of lichen in the bottom of nestlings hatch. nests. Here they can serve no purpose in camou­ The behaviour of the female on the day the flage and I believe their purpose is stmctural, like first nestling hatches seems to be much less crucial the iron in reinforced concrete. They help to give in determining when the second nestling hatches. some rigidity to the nest which cannot be provided Demands 011 her time for feeding the nestling would by the other materials. be light and she would still need to brood it and The lichens on the outside of the nest incubate the remaining egg. Her time on the nest undoubtedly provide camouflage, thus reducing should change little. predation from animals that hunt visually. However, In neither case when the nestlings hatched 2 they can have no role to play in deterring those days apart (Table 4; 12.1, 18) was the duration of that hunt by olfaction, and many eggs or young incubation 16 days but 17 days for both pairs of that have disappeared from the nests have proba­ nestlings. Assuming that 16 days for incubation is bl y been taken by two snake species, Chironius more efficient because it is shorter, then neither carinatus (machette savanne) and Pseustes poe­ female found the optimum schedule. This suggests cillonotus (liane snake). Sick (1993) suggested that that some females judge better than others the time lichens may also provide protection against rain. that needs to be spent on the nest. One female, on Egg laying, egg hatching and jledging.­ nest 10.1, did not sit on the nest during the night Hummingbirds usually lay their eggs early in the before she laid the second egg. Her first egg morning (Skutch 1973, Johnsgard 1997), which hatched in 18 days and the omission of that night's occurred in this study. Both the hatching aud incubation probably contributed significantly to fledging of the nestlings also occuned early most the lengthened incubation. But, to judge from the of the time, though there is evidence that at least record, the same female seldom performs the same one hatched in the afternoon. way twice. Of the three females who used one nest Incubation period.-The incubation period of more than once (nests 7.2 and 7.4; 12.1, 12.2 and hummingbirds ranges from 9-23 days (Johnsgard 12.3; 16 and 18 ; see Table 4), none performed the 1997). Variability in the duration of incubation in same way twice. This suggests that the female re­ this study was greater than expected. The first egg sponds to the vagaries of the situation rather than hatched in 16-18 days and the second in 16- 17 being constrained by heredity. days. The mean duration for the first egg is 17.2 Nestling period.-As expected, the duration of days and I 6.5 for the second. This difference is al­ the nestling period is much more variable than the most certainly due to the behaviour of the female duration of incubation, ranging from 20-26 days. during the first 2 days of incubation when only the Initially I was disinclined to accept as possible a first egg is in the nest. [f she incubated with equal period as short as 20 days, but when another oc­ intensity throughout the incubation petiod as with cuned (nest 28.1; Table 5) it seemed more likely many hummingbirds (Johnsgard 1997), the nest­ than predation atthe same age. Skutch (1973) gives lings should have hatched 2 days apart. Among the 20-23 days for fledging of both Costa's Humming­ nests observed this happened twice (Table 4) . bird (Calypte costae) and the Little Hermit (Phae­ More usually, when the eggs were laid 2 days apart thornis longuemareus), and 19-23 days for the the nestlings hatched 1 day apart, so it is clear that Rufous-tailed Hummingbird (Amazilia tzacatl). the female does not usually incubate with equal in­ Johnsgard (1997) reports 22-38 days for the Ande­ tensity on all days. My notes for the female of nest an Hillstar (Choreotrochilus estella). 12.2 record that I "did not see her on nest today, Behaviour of nestlings .-How do the nestlings the 09/04/91-the day the egg was laid- though r change position? I suggest two possibilities. First, looked at least three times", whereas on I 0/04/91 in moving from a head-to-head position a nestling she was "on nest all four times I checked at about could simply crawl in front of the other and keep 0900 h., 1400 h., 1600 h., and 1745 h. Also on the going round the i11side of the nest circle, pushing 178 QUESNEL the other nestling into the position it had previous­ to their vulnerability to accidents, weather associ­ ly occupied. Second, a nestling could try to tum ated catastrophes and predation. around in its half of the nest which would probably The high success rate of the Andean Hillstar entail clambering at least partly over the other nest­ was attributed to avoidance of predation in the ling. My note which says "the larger (so it seemed) inhospitable environment in which it breeds. Sim­ shuffled around to face head-to-tail" seems to ilarly, the high success rate of the Black-throated favour the first possibility. Mango in my GHs may be due to the avoidance of Brooding period.-According to Johnsgard predators such as snakes, birds and bats which ( 1997), the brooding period of hummingbirds either may not see the nests because of the plastic ranges from 12-18 days. However, in this study the roof or may not dare to enter because of frequent brooding period was considerably shm1er, ranging human presence. from 8-12 days. There is no obvious correlation be­ Hummingbirds live relatively long lives for tween the brooding period and nestling period; the their small size. Some are known to have lived up to one female who brooded a single nestling (nest 12 years (Johnsgard 1997). The aberrant female of 28.1 ), which fi lied the nest to about half the extent this study nested in 4 successive yr and may have two nestlings would have done, did not carry on lived much longer than that. Assuming a reproduc­ any longer than the others (Table 5). This suggests tive span of 4 yr and a mean of six eggs I yr, just that the habit may be under genetic control rather two birds need to survive for 4 yr from 24 eggs to than a response to the filling of the nest. keep the population stable, i.e., 0.5 bird I year. Ifthe Reuse of nests.-The reuse of nests by the female's reproductive span were 8 yr, then only Black-throated Mango has been noted previously 0.25 birds I yr would maintain a stable population. (e.g., Snow and Snow 1974). In this study 32% were In the first case, if nestling loss is 43.5% (2.6 1 eggs used repeatedly, one four times, four three times I yr) for each of 4 yr, 3.39 nestlings fledge each yr and four twice. The intervals between occupations for a total of 13 .56 in 4 yr, and the nestling : loss for eight nests reveal two disti11ct groups, in which ratio is 10.44 : 11.56 with two adults surviving for 4 the mean of one group is nearly three times that of yr. In the second case, calculated similarly, the the other (Table 7), rather than being spread more nestling: adult loss ratio is 20.44 : 25.12. Though or less evenly between 7 and 33 days as in the the potential life span is long, most birds obviously study by Snow and Snow (1974).ln two years, 1990 die much earlier. If nestling loss arises, adult loss and 1992, there were examples of both long and falls, and vice versa. short periods by different birds. The female of nest According toR. ffrench (in !itt.), "This species, 17 waited 25 days between the first and second perhaps more than any other hummer I know builds occupations of her nest but only 12 days between its nest in a very conspicuous location (in the wild), the second and third. Thus, the interval appears to often as you have found on a Cecropia branch. It be vmiable for each individual and is probably may be well camouflaged, but it is still much easier related to fledgling survival, with a shorter interval for human eyes to locate than nests placed in forks when fledglings fail to survive until independence. or within vegetation. How does it get away with Reproductive success.-ln this study nesting this?" I suspect it can tolerate high levels of nest­ success, measured as the percentage of eggs that ling loss because of its long potential lifespan. produced fledged young, was 56.5%. Johnsgard I have never seen a predator at a hummingbird (1997) provided comparative figures for six other nest, but I assume that two diurnal snakes, Chiro­ species of which two, the Andean Hi11star and the nius carinatus and Pseustes poecilonotus will Broad-tailed Hummingbird (Selasphorus platycer­ attack hummingbirds as they are well known preda­ cus), experience similarly high reproductive success tors of birds. The loss attributed to nest destruc­ at 59.4% and 58.9%, respectively. The remaining tion may have been to another predator such as a species were less successful, ranging from 16.7% to rat, in which case the loss under nest destruction 34.4%. Johnsgard (1997) attributed the relatively would disappear and the loss to predation would low rates of reproductive success in hummingbirds increase, in the first calculation from 11.3 to 21 .0%, Breeding Biology ofthe Black-throated Mango 179 and in the second calculation from 10.3 to 19.1 %. typing the manuscript. Breeding season.-What may be the cause of the cyclic laying activity (Table 9)? Presumably the LITERATURE CITED surge in hormone levels that triggers the breeding season peaks in January and accounts for the first BELCHER, C.,ANDG. D. SMOOKER. 1936. Birds of the (largest) peak. But why the others? The evidence colony of Trinidad and Tobago, part III. Ibis comes from the nest reoccupiers (see column 3 of ser. XIII, 6:1-35. Table 9). The breeding cycle with a mean of 17 days CRJCHLOW, C.A. 1967. A predator at work. Trin. for incubation, 23 days for fledging and 14 days for Field Nat. Club J. 6:6. post-flight feeding of the nestlings is nearly 2 mo EISENBERG, J. F. 1989. Mammals of the Neotropics. long, producing a second peak of laying activity in The northern Neotropics. Vol. 1. Panama, Co­ March and a third peak in May. If this sequence of lombia, Venezuela, Guyana, Suriname, French events happened without disruption the peaks Guiana. University of Chicago Press, Chicago. would always be obvious, but various events mask 449 pp. the pattern. FFRENCH, R. 1991. A guide to the birds of Trinidad The laying peaks of birds that began nesting in and Tobago. 2nd ed. Cornell University Press, December or February would fall in the troughs of Ithaca, New York. 426 pp. the January starters. Birds that lay in January and HERKLOTS, G. A. C. 1961. The birds of Trinidad and lose their eggs may start again in Febmary. Birds Tobago. Collins, London. 287 pp. that began a first cycle in late January, reared JOHNSGARD, PA 1997. The hummingbirds of North nestlings and then waited 30 days to start a new America. Smithsonian Institution Press, Wash­ cycle would lay again in April, not March. Another ington, D. C. 278 pp. cycle after that would begin in June. Despite all QUESNEL, V. C. 1995. The case history of an aber­ this, it seems fair to predict that if we could collect rant Black-throated Mango hummingbird, An­ a sufficiently large sample in a single season, we thracothorax nigricollis. Bull. Brit. Omithol. would find three waves of laying with peaks in Club 115:25-27. January, March and May, and tl1is is what we see SICK, H. 1993. Birds in Brazil: a natural history. dimly in Table 9. Princeton University Press, Princeton, UK. 703 pp. ACKNOWLEDGEMENTS SKUTCH, A. F. 1973. The life of the hummingbird. Vineyard Books Inc., New York. 95 pp. I thank R. P. ffrench for comments on an earlier SNOW, D. W., AND B. K. SNOW. 1964. Breeding sea­ version of this manuscript and F. E. Hayes for son and annual cycles of Trinidad landbirds. providing literature. R. Ali-Hassan assisted with Zoologica 49:1-39. Pp. 180-193 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Uruv. West Indies, St. Augustine, Occ. Pap. II, 2002.

EXTINCTION-PRONE BIRDS OF TRINIDAD AND TOBAGO: MAKING PREDICTIONS FROM THEORY

STANLEY A. TEMPLE Department of Wildlife Ecology, University of Wisconsin, Madison, WI 53706, USA

ABSTRACT.-TI1eory suggests that vulnerability to extinction can be predicted, in a general way, on the basis of certain risk factors associated with a bird's life history and ecology. Using information about these risk factors, taken mostly from Richard ffrench's A Guide to the Birds of Trinidad and Tobago , I used a multiple logistic regression model to predict the relative vulnerab1lity of the landbirds of Trinidad and Tobago to extinction. The results were compared with other lists of threatened bird species for Trinidad and Tobago. The birds predicted to have the l1ighest risks of extinction seem likely to become threatened species, and they should be the targets of additional study and, possibly, conservation planning.

RESUMEN.-Te6ricamente, Ia vulnerabilidad a la extinci6n de una especie de ave puede predecirse de manera general, considerando ciertos factores de riesgo asociados a su ecologfa e historia de vida. Usando informacion relativa a estos factores, obtenida principalmente de A Guide to the Birds of Trinidad and Tobago de Richard ffrench, uti lice un modelo de regresi6n logistica m{tltiple para predecir Ia vulnerabihdad relativa ala extincion de las aves terrestres de Trinidad y Tobago. Los resultados se corre]acion­ aron fuertemente con el estatus actual de conservaci6n de estas especies. Las aves que tienen los niveles de riesgo de extincion mas altos podrian constituir especies potencial­ mente amenazadas, y deberian ser objetos de estudios adicionales y, posiblemente, de maneJO.

KEY WORDS.-birds, extinction, risk factors, threatened species, Trinidad and Tobago, vulnerability to extinction

When unusual changes occur in either the or a few populations, species in which population physical or biotic environment, populations of cer­ size is small, populations with low population den­ tain birds will decline, and some may go extinct. sity, species that need large home ranges, species Theory suggests that the vulnerability of a pop­ that have large body size, species with low rates of ulation to extinction can be predicted on the basis reproduction, species that have poor dispersal of certain characteristics of the species' life history abilities, species that migrate, species with special­ and ecology (Terborgh 1974, Terborgh and Winter ised niche requirements, species that have aggre­ 1980, Pimm et al. 1988, Primack 1998, Gaston and gated dispersion patterns, and populations that are Blackburn 1995). The populations that are predicted hunted by people. to be most vulnerable to extinction include: species These characteristics of extinction-prone birds with narrow geographic ranges, populations at tl1e (risk factors) are not independent of one another; edge of the species' range, species with only one some are typically found as a correlated suite of

180 Extinction-prone Birds of Trinidad and Tobago 181 life-history traits (e.g., vulnerable K-selected spe­ METHODS cies often have large body size, low population density, low reproductive rate, etc.). Tite more risk I restricted my analyses to 272 species of factors a species' population possesses, the high­ landbirds that have been recorded as either resi­ er will be its predicted risk of extinction. Conser­ dents or breeders on the islands of Trinidad and vationists can use these traits to anticipate which Tobago, thus excluding seabirds, vagrants and species in a regional avifauna may be prone to ex­ seasonal migrants from the north and south. For tinction and, hence, need monitoring and preemp­ these focal species, I compiled information on their tive conservation planning. life histories and ecologies from ffrench (199 I), Birds on the islands of Trinidad and Tobago Dunning (1992), Morony et al. (1975), Meyer de have been subjected to several well-known, human­ Schauensee and Phelps (1978) and other sources. caused threats that often cause populations to be­ I recorded information on the following 13 factors come extinct. Habitats of some species (e.g., dry that are thought to be related to extinction risk: forests, wetlands, savannas) have been reduced, Size of range.-A species was categorised as degraded and fragmented, and some species (e.g., having a narrow geographic range if it was restrict­ game birds, cage birds) are subject to intense over­ ed to an area of less than 100 krn2 in Trinidad and exploitation. In the face of these and other threats, Tobago (e.g., Scaled Antpitta). populations of a few species (e.g., Homed Screamer Position within the species' geographic and Blue-and-yellow Macaw) have already become range.-A population in either Trinidad or Tobago extinct, and populations of many others have de­ was categorized as being at the edge of its geo­ clined. graphic range if there were no resident populations The prospects for wildlife conservation efforts either in South America or on other Caribbean is­ in Trinidad and Tobago have improved recently as lands to the north. a result of new policies and legislation (e.g., the Limited number of populations.-A species Co11servation of Wildlife Bill of 1999), and there is was categorized as having a limited number of now a need to identity those species of birds most populations if there was only one population occu­ vulnerable to extinction so they can be targeted for pying an area less than 100 km2 on either Trinidad study and management attention. There is, how­ or Tobago (e.g., White-tailed Sabrewing). ever, little quantitative information to suggest Population density.-A species was categor­ which bird species may be at risk, and the only lists ized as having a low population density if the of threatened species in Trinidad and Tobago (e.g., appropriate allometric equation relating population the regional lists of Collar and Andrew 1988, density to body mass and diet (see Peters 1983 for Groombridge 1993, Stotz et a1. 1996, Collar et al. a review) indicated that there was less than one 1992, 1997, and the local list that accompanies the individual per km 2 (e.g., Orange-breasted Falcon). Conservation of Wildlife Act of 1999) either take a Small population size.-A species was catego­ global rather than island-scale view of endanger­ rised as having a small population on either Trini­ ment or are largely speculative. dad or Tobago if its estimated population density Tite excellent compilation of life-history infor­ multiplied by the approximate area of suitable hab­ mation by ffrencl1 (1991) provides a basis for using itat (estimated from 1994 aerial photos) was less theory to predict the bird species that are most than 200 individuals (e.g., Rufous Crab-Hawk). prone to extinction in Trinidad and Tobago. In this Home range size.-A species was categorised paper, I have used information from ffrench (I 991) as needing a large horne range if the appropriate and other sources to predict and rank the relative allometric equation relating home range size to vulnerabilities of the islands' birds. To my know­ body mass and diet (Peters 1983) or other infor­ ledge, the approach I have used in this paper to mation indicated that the home range size was identify birds potentially at risk has never been greater than I km2 (e.g., the Ornate Hawk-eagle). applied in a systematic way to any other regional Body size.-A species was categorised as hav­ avifauna. ing a large body size if the body mass of the larger 182 TEMPLE sex exceeded 500 g (e.g., Great Black-Hawk). dieting rarity and vulnerabillty to extinction. Reproductive rate.-A species was categorised I next applied the logistic regression model as having a low rate of reproduction if it was in­ (that included only the significant risk factors) to capable of raising more than two offspring annually the full list of landbird species from Trinidad and (e.g., Band-tailed Pigeon). Tobago. Based on the significant risk factors Dispersal abilities.-A species was categorized possessed by each species, the model predicted its as a poor disperser if it is found on either Trinidad log odds of being at risk of extinction (y). Based on or Tobago but not on both islands (which are with­ these calculated log odds, the probability of being ill sight of one another and separated by only 30 at risk (with a range of values from 0 for a species km). having no risk factors to 1.0 for a species having all Migratory status.-A species that breeds in risk factors) was calculated as &' I (1 +&'). I used Trinidad and Tobago but migrates during the non­ these probabilities to rank the species from most to breeding season was categorised as migratory (e.g., least vulnerable to extinction. For species with the Swallow-Tanager). same probabilities of being at risk, 1 further ranked Narrow niche.-Although decisions were them according to the total number of risk factors somewhat subjective, a species was categorised as they possessed (out of 13 ). having a specialised niche requirement if it needed To determine how well these vulnerability pre­ some very specific resource (habitat, food, nest dictions were correlated with the current status of site, etc.) that was always or often in limited supply species in Trinidad and Tobago, I compared the in Trinidad and Tobago (e.g., Oilbird's requirement vulnerability ranking of each species with its status for caves). on local, regional and global lists of threatened Dispersion pattern.-A species was categor­ spee1es. ised as having an aggregated dispersion pattern if a high proportion of its population in Trinidad and RESULTS Tobago is found in a few flocks (e.g., Scarlet Ibis roosting in Caroni Swamp). Tables I and 2 list the analysed bird species of Exploitation status.-A species that is taken Trinidad and Tobago in descending order of their (i .e., killed or captured) by people was categorised calculated vulnerability to extinction. Risk factors as an exploited species (e.g., Trinidad Piping-Guan). possessed by each species are also given. The From the list of all landbird species, I singled vulnerability to extinction in Trinidad, for example, out the 57 species that were categorised by ffrench ranges from a high value of 1.0, in the case 47 spe­ (1991) as eitl1errare or extirpated (plus a few he des­ cies, to a low value of 0, in the case of most remain­ cribed as "uncommon" or "rather uncommon" that ing species. have subsequently been judged rare). I assumed The logistic regression analysis identifies the that these species were likely to be vulnerable to relative impacts of different risk factors on vulner­ extinction by virtue of their rarity, even though ability to extinction. Six of the 13 explanatory varia­ ffrench made no decisions on whether or 11ot most bles made significant contributions to predicting of these species were actually threatened. r then vulnerability ofbirds in Trinidad, with three signi­ used multiple logistic regression (Wilkinson et al. ficant explanatory variables for Tobago (Table 3). 1996) to analyse the categorical data on risk factors As might be expected, there was a generally for all bird species. The binary response variable poor correlation between the calculated vulner­ was coded as either 1 (listed as rare or extirpated) or abilities to extinction for a species at the island 0 (not listed). The 13 binary explanatory variables scale and its inclusion on global and regional lists (risk factors) were coded as either I (possesses the of threatened species which focus on endanger­ risk factor) or 0 (does not possess the risk factor). ment at larger scales. There was, however, a better The logistic regression analysis identified the fea­ correspondence between calculated vulnerability to tures of life history and ecology (risk factors) that extinction and inclusion on the current list of made a significant (P < 0.15) contribution to pre- species that will receive special protection under Extinction-prone Birds of Trinidad and Tobago 183

TABLE 1. Risk factors and vulnerability to extinction for the landbird species of Trinidad (including Bocas Islands), which are arranged in descending order of vulnerability. Taxonomy follows the American Or­ nithologists' Union and Meyer de Schauensee (1970).

Vulnerability Species Risk factors• to extinctionb Blue-and-yellow Macaw (Ara ararauna)c A,B,C,D,E,F,G,H,K,L,M 1.00 Band-tailed Pigeon (Columba fasciata) A,B,C,D,E,F,G,H,I,L,M 1.00 Homed Screamer (Anhima cornuta) c A,B,C,D,E,F,G,H,l,L,M 1.00 Trinidad Piping-Guan (Pipile pipile) A,B,C,D,E,F,G,H,I,L,M 1.00 Yellow-crowned Parrot (Amazona ochrocephala) A,B,C,D,E,F,G,I,K,L,M 1.00 Boat-billed Heron ( Cochlearius cochlearius) A,B,C,D,E,F,I,K,L,M 1.00 Limpkin (Aramus guarauna) A,B,C,D,F,G,I,K,L,M 1.00 Oilbird (Steatornis caripensis) A,B,D,E,F,G,I,K,L,M 1.00 Red-bellied Macaw (Ara manilata) A,B,C,E,F,H,I,K,L,M 1.00 Rufescent Tiger-Heron (Tigrisoma lineatum) A,B,D,E,F,G,H,I,K,M 1.00 Rufous Crab-Hawk (Buteogallus aequinoctialis) A,B,C,D,E,F, G,H,I,K 1.00 Black-collared Hawk (Busarellus nigricollis) A,B,C,D,E,F,G,H,l 1.00 Orange-breasted Falcon (Falco deiroleucus) A,B,C,D,E,F ,G,H,l 1.00 W11ite-tailed Goldenthroat (Polytmus guainumbi) A,B,C,D,E,H,I,J,K 1.00 W11ite-tailed Hawk (Buteo albicaudatus) A,B,D,E,F,G,H,I,M 1.00 Ash-throated Crake (Porzana albicollis) A,B,C,D,E,I,K,M 1.00 Azure Gallinule (Porphyrulajlavirostris) A,B,C,D,E,I,K,M 1.00 Golden-rumped Euphonia (Euphonia cyanocephala) A,B,C,D,E,H,I,M 1.00 Crested Doradito (Pseudocolopteryx sclateri) A,B,C,D,E,H,I,J 1.00 Dark-billed Cuckoo (Coccyzus melacoryphus) A,B,C,D,E,H,I,K 1.00 King Vulture (Sarcoramphus papa) B,D,E,F,G,H,I,K 1.00 Moriche Oriole (Icterus chrysocephalus) A,B,C,D,E,H,I,M 1.00 Rufous-necked Wood-Rail (Aramides axillaris) A,B,C,D,E,I,K,M 1.00 Scaled Antpitta ( Grallaria guatimalensis) A,B,C,D,E,H,I,K 1.00 Slate-colored Seedeater (Sporophila schistacea) A,B,C,D,E,H,I,M 1.00 Spotted Rail (Pardirallus maculatus) A,B,C,D,E,I,K,M 1.00 Straight-billed Woodcreeper (Xiphorhynchus picus) A,B,C,D,E,H,I,K 1.00 Sun grebe (Heliornis fulica ) A,B,C,D,E,H,I,K 1.00 Swallow-Tanager (Tersina viridis) A,B,C,D,E,l,J,K 1.00 Gray Seedeater (Sporophila intermedia) A,B,D,E,H,I,M 1.00 Hook-billed Kite (Chondrohierax uncinatus) D,E,F,G,H,I,K 1.00 Lesser Elaenia (Elaenia chiriquensis) B,C,D,E,H,I,K 1.00 Olive-striped Flycatcher (Mionectes olivaceus) A,B,C,D,E,H,I 1.00 Red-capped Cardinal (Paroaria gularis) A,B,C,D,E,H,I 1.00 Red Siskin (Carduelis cucullata) A,B,C,D,E,I,M 1.00 Stripe-backed Bittern (Ixobrychus involucris) A,B,D,E,F,I,K 1.00 W11ite-faced Whistling-Duck (Dendrocygna viduata) A,D,E,F,G,L,M 1.00 Blue-capped Tanager (Thraupis cyanocephala) A,B,C,D,H,l 1.00 Mouse-colored Tyrannulet (Phaeomyias murina) A,B,C,D,H,I 1.00 Orange-billed Nightingale-Thrush ( Catharus aurantiirostris) A,B,C,D,E,l 1.00 Rufous-shafted Woodstar (Chaetocercus jourdanii) A,B,C,D,H,I 1.00 Spotted Tody-Fiycatcher (Todirostrum maculatum) A,B,C,D,H,I 1.00 184 TEMPLE

TABLE 1 continued.

Vulnerability Species Risk factorsa to extinctionb Streaked Saltator (Saltator striatipectus) A,B,C,D,E,I 1.00 Sulphury Flycatcher (Tyrannopsis sulphurea) A,B,D,H,l,K 1.00 Pearl Kite ( Gampsonyx swainsonii) A,B,C,D,I 1.00 Black-faced Grassquit (Tiaris bicolor) A,C,D,E 1.00 Mangrove Cuckoo (Coccyzus minor) A,D,E,K 1.00 Blue Ground-Dove (Claravis pretiosa) B,D,E,F,H,I,M 0.94 Great-billed Seed-Finch (01yzoborus crassirostris) B,D,E,H,I,M 0.94 Lesser Seed-Finch ( Oryzoborus angolensis) B,D,E,H,I,M 0.94 Ruddy-breasted Seedeater (Sporophila minuta) D,E,H,M 0.94 Yellow-bellied Seedeater (Sporophila nigricollis) D,E,H,M 0.94 Lesson's Seedeater (Sporophila bouvronides) D,E,M 0.94 Mottled Owl (Ciccaba virgata) B,D,E,F,H,I 0.78 White-fringed Antwren (Formicivora grisea) C,D,E,H 0.78 American Kestrel (Falco sparverius) C,D,E 0.78 Anhinga (Anhinga anhinga) B,D,K,M 0.49 Zone-tailed Hawk (Buteo albonotatus) B,D,E,F,G,H,I,M 0.43 Ornate Hawk-Eagle (Spizaetus omatus) D,E,F,G,H,M 0.43 Chapma's Swift (Chaetura chapmani) B,D,F,H,I,K 0.17 Least Grebe (Tachybaptus dominicus) D,K 0.17 Pied-billed Grebe (Podilymbus podiceps) D,K 0.17 Long-winged Harrier (Circus buffoni) D,E,F,G,H 0.14 Scarlet Ibis (Eudocimus ruber) A,B,C,F ,G,J,K,L,M 0.10 Gray Hawk (Asturina nitida) B,E,F,G,H,I 0.00 Plumbeous Kite (Jctinia plumbea) B,E,F,H,I,J 0.00 White Hawk (Leucopternis albicollis) B,E,F,G,H,I 0.00 Bat Falcon (Falco rufigularis) B,E,F,H,I 0.00 Black-bellied Whistling-Duck (Dendrocygna autumnalis) E,F,G,L,M 0.00 Chestnut-co11ared Swift (Cypseloides rutilus) B,F,H,I,K 0.00 Double-toothed Kite (Harpagus bidentatus) B,E,F,I,J 0.00 Savanna Hawk (Buteogallus meridionalis) B,F,G,H,I 0.00 Silvered Antbird (Sclateria naevia) A,B,H,l,K 0.00 Spectacled Owl (Pulsatrix per~picillata) B,E,F,H,l 0.00 Turkey Vulture (Cathartes aura) B,F,G,H,I 0.00 Yellow-headed Caracara (Milvago chimachima) B,F,G,H,I 0.00 Band-rumped Swift (Chaetura spinicauda) B,F,I,K 0.00 Black Vulture (Coragyps atratus) B,F,G,I 0.00 Blue-headed Parrot (Pionus menstruus) B,F,l,K 0.00 Common Black-Hawk (Buteogallus anthracinus) E,F,G,H 0.00 Gray-fronted Dove (Leptotila rufaxilla) B,H,I,M 0.00 Gray-headed Kite (Leptodon cayanensis) B,E,F,l 0.00 Gray-necked Wood-Rail (Aramides cajanea) B,E,l,M 0.00 Great Black-Hawk (Buteogallus urubitinga) E,F,G,H 0.00 Green-throated Mango (Anthracothorax viridigula) A,B,H,I 0.00 Little Cuckoo (Piaya minuta) A,B,H,I 0.00 Extinction-prone Birds of Trinidad and Tobago 185

TABLE 1 continued.

Vu In erability SEecies Risk factors" to exinctionb Little Tinamou (Crypturellus soui) B,H,I,M 0.00 Orange-winged Parrot (Amazona amazonica) F,G,K,M 0.00 Plain-breasted Ground-Dove (Columbina minuta) B,H,I,M 0.00 Scaled Pigeon (Columba speciosa) B,H,I,M 0.00 Short-tailed Hawk (Buteo brachyurus) B,E,F,I 0.00 Swallow-tailed Kite (Elanoides forficatus) B,F,I 0.00 Bay-headed Tanager (Tangara gyrola) B,H,I 0.00 Bearded Bellbird (Procnias averano) B,H,I 0.00 Bicolored Conebill (Conirostrum bicolor) A,B,I 0.00 Black-crested Antshrike (Sakesphorus canadensis) B,H,I 0.00 Black-crowned Night-Heron (Nycticorax nycticorax) F,G,M 0.00 Black-faced Antthrush (Formicarius analis) B,H,I 0.00 Blue-chinned Sapphire (Chlorestes notatus) B,H,I 0.00 Blue Dacnis (Dacnis cayana) B,H,I 0.00 Blue-tailed Emerald (Chlorostilbon mellisugus) B,H,J 0.00 Bran-colored Flycatcher (Myiophobus fasciatus) B,H,I 0.00 Brown Violet-ear (Colibri delphinae) B,H,I 0.00 Clapper Rail (Rallus longirostris) E,I,M 0.00 Bam Owl (Tyto alba) E,F,G 0.00 Common Ground-Dove (Columbina passerina) H,I,M 0.00 Common Pauraque (Nyctidromus albicollis) B,H,I 0.00 Crimson-crested Woodpecker (Campephilus melanoleucos) B,H,I 0.00 Forest Elaenia (Myiopagis gaimardii) B,H,I 0.00 Fork-tailed Palm-Swift (Reinarda squamata) B,F,I 0.00 Golden-headed Manakin (Pipra erythrocephala) B,H,I 0.00 Gray-breasted Crake (Laterallus exilis) B,I,M 0.00 Green Hermit (Phaethornis guy) B,H,I 0.00 Green Honeycreeper ( Chlorophanes spiza) B,H,I 0.00 Lesser Swallow-tailed Swift (Panyptila cayennensis) B,F,I 0.00 Lilac-tailed Parrotlet (Touit batavica) B,I,K 0.00 Little Hermit (Phaethornis longuemareus) B,H,I 0.00 Long-bil1ed Gnatwren (Ramphocaenus melanurus) B,H,I 0.00 Long-bj]Jed Starthroat (Heliomaster longirostris) B,H,I 0.00 Nacunda Nighthawk (Podager nacunda) B,H,I 0.00 Pale-vented Pigeon (Columba cayennensis) B,H,M 0.00 Pinnated Bittem (Botaurns pinnatus) E,F,M 0.00 Purple Honeycreeper (Cyanerpes caeruleus) B,H,I 0.00 Ruddy Ground-Dove (Columbina talpacoti) B,H,M 0.00 Ruddy Quail-Dove (Geotrygon montana) B,H,M 0.00 Rufous Nightjar ( Caprimulgus rufus) B,H,I 0.00 Short-tailed Nighthawk (Lurocalis semitorquatus) B,H,I 0.00 Short-tailed Pygmy-Tyrant (Myiornis ecaudatus) B,H,I 0.00 Speckled Tanager (Tangara guttata) B,H,I 0.00 Squirrel Cuckoo (Piaya cayana) B,H,I 0.00 186 TEMPLE

TABLE 1 continued.

Vulnerability SEecies Risk factorsa to extinctionb Steaked Xenops (Xenops rutilans) B,H,I 0.00 Trinidad Euphonia (Euphonia trinitatis) B,l,M 0.00 Tropical Pewee (Contopus cinereus) B,H,I 0.00 Tufted Coquette (Lophornis ornata) B,H,I 0.00 Violaceous Trogon (Trogon violaceus) B,H,I 0.00 White-bearded Manakin (Manacus manacus) B,H,I 0.00 White-bellied Antbird (Myrmeciza longipes) B,H,I 0.00 White-cheeked Pintail (Anas bahamensis) F,G,M 0.00 White-chested Emerald (Amazilia chionopectus) B,H,I 0.00 White-flanked Antwren {Myrmotherula axillaris) B,H,l 0.00 White-tailed Trogon (Trogon viridis) B,H,I 0.00 Yellow-breasted Crake (Porzana flaviventer) B,l,M 0.00 Yellow-crowned Night-Heron (Nyctanassa violaceus) F,G,M 0.00 Y ellow-rumped Cacique ( Cacicus eela) B,H,I 0.00 Pygmy Kingfisher ( Chloroceryle aenea) B,I 0.00 Black-necked Stilt (Himantopus mexicanus) H,J 0.00 Black-tailed Tityra (Tityra cayana) B,J 0.00 Blue-and-white Swallow (Notiochelidon cyanoleuca) B,l 0.00 Boat-billed Flycatcher (Megm)mchus pitangua) B,I 0.00 Bright-rumped Attila (Attila spadiceus) B,I 0.00 Channel-billed Toucan (Ramphastos vitellinus) B,l 0.00 Chestnut Woodpecker (Celeus elegans) B,I 0.00 Cocoa Thrush (Turdusfumigatus) B,I 0.00 Collared Plover (Charadrius collaris) H,J 0.00 Common Potoo (Nyctibius griseus) H,l 0.00 Common Snipe ( Gallinago gallin ago) H,J 0.00 Eared Dove (Zenaida auriculata) H,M 0.00 Euler's Flycatcher (Lathrotriccus euleri) B,l 0.00 Ferruginous Pygmy-Owl (Glaucidium brasilianum) B,I 0.00 Golden-crowned Warbler (Basileuterus culicivorus) B,l 0.00 Golden-fronted Greenlet (Hylophilus aurantiiFons) B,l 0.00 Gray-breasted Martin (Progne chalybea) B,I 0.00 Gray-romped Swift ( Chaetura cinereiventris) F,K 0.00 Grayisll Saltator (Saltator coerulescens) B,I 0.00 Great Antshrike {Taraba major) B,I 0.00 Greater Ani (Crotophaga major) B,l 0.00 Green-rumped Parrotlet (Forpus passerinus) K,M 0.00 Hepatic Tanager (Piranga jlava) B,I 0.00 Lineated Woodpecker (Dryocopus lineatus) B,l 0.00 Lined Quail-Dove (Geotrygon linearis) H,M 0.00 Northern Scrub-Flycatcher (Sublegatus arenarum) B,I 0.00 Pale-breasted Spinetail (Synallaxis albescens) B,l 0.00 Purple GalHnule (Porphyrula martinica) H,M 0.00 Red-crowned Ant-Tanager (Habia rubica) B,I 0.00 Extinction-prone Birds of Trinidad and Tobago 187

TABLE 1 continued.

Vulnerability S:eecies Risk factors" to extinctionb Rufous-browed Peppershrike (Cyclarhis gujanensis) B,I 0.00 Saffron Finch (Sica/is jlaveola) B,I 0.00 Short-tailed Swift (Chaetura brachyura) F,K 0.00 Silver-beaked Tanager (Ramphocelus carbo) B,I 0.00 Slaty-capped Flycatcher (Leptopogon superciliaris) B,l 0.00 Smooth-billed Ani (Crotophaga ani) B,l 0.00 Sooty Grassquit (Tim·is fuliginosa) B,l 0.00 Southern Beardless-Tyrannulet ( Camptostoma obsoletum) B,l 0.00 Southern Rough-winged Swallow (Stelgidopteryx ruficollis) B,I 0.00 Streaked-headed Woodcreeper (Lepidocolaptes souleyetii) B,l 0.00 Tropical Pantla (Parula pitiayumi) B,l 0.00 Turquoise Tanager (Tangara mexicana) B,I 0.00 White-shouldered Tanager (Tachyphonus luctuosus) B,l 0.00 White-tailed Kite (Elanus leucurus)" B,I 0.00 White-tipped Dove (Leptotila verreauxi) H,M 0.00 White-winged Swallow (Tachycineta albiventer) B,I 0.00 Yellow-hooded Blackbird (Agelaius icterocephalus) B,I 0.00 Yellow-olive Flycatcher (Tolmomyias sulphurescens) B,T 0.00 Yellow Oriole (Icterus nigrogularis) B,I 0.00 Yellow-chinned Spinetail (Certhiaxis cinnamomea) B,T 0.00 Black-throated Mango (Anthracothorax nigricollis) H 0.00 Broad-winged Hawk (Buteo platypterus) F 0.00 Cocoa Woodcreeper (Xiphorhynchus susurrans) H 0.00 Collared Trogon (Trogon collaris) H 0.00 Common Moorhen ( Gallinula chloropus) M 0.00 Copper-rumped Hummingbird (Amazilia tobaci) H 0.00 Crested Oropendola (Psarocolius decumanus) H 0.00 Gray-throated Leaftosser (Sclerurus albigularis) H 0.00 Lesser Nighthawk ( Chordeiles acutipennis) H 0.00 Little Blue Heron (Egretta caerulea) M 0.00 Masked Duck (Nomonyx dominicus) M 0.00 Plain Antvireo (Dysithamnus mentalis) H 0.00 Plain-brown Woodcreeper (Dendrocinclafuliginosa) H 0.00 Red-legged Honeycreeper (Cyanerpes cyaneus) H 0.00 Ruby-topaz Hummingbird (Chrysolampis mosquitus) H 0.00 Rufous-breasted Hermit ( Glaucis hirsuta) H 0.00 Tropical Screech-Owl (Otus choliba) I 0.00 Violaceous Euphonia (Euphonia violacea) M 0.00 Wattled Jacana (Jacana jacana) M 0.00 White-necked Jacobin (Florisuga mellivora) H 0.00 White-tailed Nightjar (Caprimulgus cayennensis) H 0.00 Yellow-legged Thrush (Platycichlajlavipes) H 0.00 Bananaquit (Coerebajlaveola) 0.00 Bare-eyed Robin (Turdus nudigenis) 0.00 188 TEMPLE

TABLE 1 continued.

Vulnerability Species Risk factors" to extinctionb Barred Antshrike (Thamnophilus doliatus) 0.00 Blue-black Grassquit (Volatinia jacarina) 0.00 Blue-crowned Motmot (Momo tus momota) 0.00 Blue-gray Tanager (Thraupis episcopus) 0.00 Brown-crested Flycatcher (Myiarchus tyrannulus) 0.00 Carib Grackle (Quiscalus lugubris) 0.00 Cattle Egret (Bubulcus ibis) 0.00 Dusky-capped Flycatcher (Myiarchus tuberculifer) 0.00 Fuscous Flycatcher ( Cnemotriccus ji1scatus) 0.00 Giant Cowbird (Scaphidura oryzivora) 0.00 Golden-olive Woodpecker (Piculus rubiginosus) 0.00 Gray Kingbird (Tyrannus dominicensis) 0.00 Great Kiskadee (Pitangus sulphuratus) 0.00 Green Kingfisher (Chloroceryle americana) 0.00 House Wren (Troglodytes aedon) 0.00 Least Bittern (Jxobrychus exilis) 0.00 Ochre-bellied Flycatcher (Mionectes oleagineus) 0.00 Palm Tanager (Thraupis palmarum) 0.00 Pied Water-Tyrant (Fluvicola pica) 0.00 Piratic Flycatcher (Legatus leucophaius) 0.00 Red-breasted Blackbird (Leistes superciliaris) 0.00 Red-eyed Vireo (Vireo olivaceus) 0.00 Red-rumped Woodpecker (Veniliornis kirkii) 0.00 Rufous-breasted Wren (Thryothorus rutilus) 0.00 Rufous-tailed Jacamar (Galbula ruficauda) 0.00 Shiny Cowbird (Molothrus bonariensis) 0.00 Snowy Egret (Egretta thula) 0.00 Sonthem Lapwing (Vanellus chilensis) 0.00 Streaked Flycatcher (Myiodynastes maculatus) 0.00 Striated Heron (Butorides striatus) 0.00 Stripe-breasted Spinetail (Synallaxis cinnamomea) 0.00 Tricolored Heron (Egretta tricolor) 0.00 Tropical Kingbird (Tyrannus melancholicus) 0.00 Tropical Mockingbird (Mimus gilvus) 0.00 White-headed Marsh-Tyrant (Fluvicola leucocephala) 0.00 White-lined Tanager (Tachyphonus rufus) 0.00 White-necked Thrush (Turdus albicollis) 0.00 W11ite-throated Spadebill (Platyrinchus mystaceus) 0.00 White-winged Becard (Pachyramphus polychopterus) 0.00 Yellow-belhed Elaenia (Elaeniajlavogaster) 0.00 Yellow-breasted Flycatcher (Tolmomyias flaviventris) 0.00 "risk factors are: A) species with 11anow geographic range, B) population at the edge of the species' range, C) species with only one restricted population, D) species in which population size is small, E) low population density, F) species that needs large home ranges, G) species that has large body size, H) Extinction-prone Birds of Trinidad and Tobago 189

TABLE 1 continued.

species with low rate of reproduction, I) species that is not an effective disperser, J) species that migrates, K) species with specialized niche requirements, L) species that has an aggregated dispersion pattern, M) species that is hunted by people bvulnerability to extinction potentially varies from 0-1.0 and is calculated using the categorical data on risk factors for each species in a logistic regression model described in the text; species with the same calculated probability of being at risk are ranked according to the total number of risk factors they possess cpresumed extirpated

TABLE 2. Risk factors and vulnerability to extinction for the land bird species ofTobago, which are arranged in descending order of vulnerability. Taxonomy follows the American Ornithologists' Union and Meyer de Schauensee (1970).

Vulnerability Species Risk factors• to extinctionb Striped Owl (Asia clamator) A,B,C,D,E,F,G,I,K 1.00 Spotted Rail (Pardirallus maculatust A,B,C,D,E,l,K,M 1.00 Blue-chinned Sapphire (Chlorestes notatusY A,B,C,D,E,H,I 1.00 Great Black-Hawk (Buteo gallus urubitinga) A,C,D,E,F,G,H 1.00 Variable Seedeater (Sporophila americana) A,B,C,D,E,l,M 1.00 White-tailed Sabrewing (Campylopterus ensippenis) A,B,C,D,E,H,l 1.00 Common Potoo (Nyctibius griseus) A,C,D,E,H,K 1.00 Gray-throated Leaftosser (Sclerurus albigularis) A,B,C,D,E,H 1.00 Giant Cowbird (Scaphidura o1yzivora) A,B,C,D,E 1.00 Mangrove Cuckoo ( Coccyzus minor) A,C,D,E,K 1.00 Red-breasted Blackbird (Leistes superciliaris) A,B,C,D,E 1.00 Anhinga (Anhinga anhinga) A,B,C,D,K,M 0.99 Black-crowned Night-Heron (Nycticorax nycticorax) A,C,D,F,G,M 0.99 Wattled Jacana (Jacanajacana) A,C,D,M 0.99 Snowy Egret (Egretta thula) A,C,D 0.99 Black-bellied Whistling-Duck (Dendrocygna autumnalis) A,B,C,E,F,G,K,L,M 0.98 Ruddy-breasted Seedeater (Sporophila minuta) B,D,E,H,M 0.84 Lined Quail-Dove(Geotrygon !inearis)" A,B,C,H,M 0.77 White-cheeked Pintail (Anas bahamensis) A,C,F,G,M 0.77 Collared Trogon (Trogon collaris) A,B,C,H 0.77 Tricolored Heron (Egretta tricolor) A,C 0.77 White-necked Thrush (Turdus albicollis) B,D 0.22 Bam Owl (Tyto alba) E,F,G 0.18 Orange-winged Parrot (Amazona amazonica) B,F,G,K,M 0.01 Yellow-headed Caracara (Milvago chimachima) B,F,G,H,I 0.01 Pale-vented Pigeon (Columba cayennensis) A,B,H,M O.Ql Blue-backed Manakin ( Chiroxiphia pareola) A,B,H O.oJ Eared Dove (Zenaida auriculata) H,J,M 0.01 Green-rumped Parrotlet (Forpus passerinus) B,K,M 0.01 Plain-brown Woodcreeper (Dendrocincla fuliginosa) B,H,K 0.01 190 TEMPLE

TABLE 2 continued.

Vulnerability SEecies Risk factors" to extinctionb Purple Gallinule (Porphyrula martinica) A,H,M 0.01 Rufous-vented Chachalaca (Ortalis ruficauda) F,I,M 0.01 White-necked Jacobin (Florisuga mellivora) A,B,H 0.01 Yellow-crowned Night-Heron (Nyctanassa violaceus) F,G,M 0.01 Black-throated Mango (Anthracothorax nigricollis) B,H 0.01 Cocoa Woodcreeper (Xiphorhynchus susurrans) B,H 0.01 Caribbean Martin (Progne dominicensis) B,H 0.01 Collared Plover (Charadrius collaris) H,J 0.01 Common Moorhen ( Gallinula chloropus) A,M 0.01 Gray-rumped Swift (Chaetura cinereiventris) F,K 0.01 Green Kingfisher (Chloroceryle americana) A,B 0.01 Little Blue Heron (Egretta caerulea) A,M 0.01 Olivaceous Woodcreeper (Sittasomus griseicapillus) B,H 0.01 Plain Antvireo (Dysithamnus mentalis) B,H 0.01 Red-crowned Woodpecker (Melanerpes rubricapillus) B,I 0.01 Red-legged Honeycreeper (Cyanerpes cyaneus) B,H 0.01 Ruby-topaz Hummingbird (Ch1ysolampis mosquitus) B,H 0.01 Short-tailed Swift (Chaetura brachyura) F,K 0.01 Smooth-billed Ani ( Crotophaga ani) B,I 0.01 Venezuelan Flycatcher (Myiarchus venezuelensis) B,I 0.01 White-fringed Antwren (Formicivora grisea) B,H 0.01 White-tipped Dove (Leptotila verreauxi) H,M 0.01 Barred Antshrike (Thamnophilus doliatus) B 0.01 Blue-crowned Motmot (Momotus momota) B 0.01 Blue-gray Tanager (Thraupis episcopus) B 0.01 Broad-winged Hawk (Buteo platypterus) F 0.01 Brown-crested Flycatcher (Myiarchus tyrannulus) B 0.01 Copper-mmped Hummingbird (Amazilia tobaci) H 0.01 Crested Oropendo1a (Psarocolius decumanus) B 0.01 Fusco us Flycatcher ( Cnemotriccus fuscatus) B 0.01 Golden-olive Woodpecker (Piculus rubiginosus) B 0.01 Lesser Nighthawk ( Chordeiles acutipennis) H 0.01 Ochre-bellied Flycatcher (Mionectes oleagineus) B 0.01 Red-eyed Vireo (Vireo olivaceus) B 0.01 Red-rumped Woodpecker ( Veniliornis kirkii) B 0.01 Rufous-breasted Hermit (Glaucis hirsuta) H 0.01 Rufous-breasted Wren (Th1yothorus rutilus) B 0.01 Rufous-tailed Jacamar (Galbula ruficauda) B 0.01 Scrub Greenlet (Hylophilus flavipes) B 0.01 Streaked Flycatcher (Myiodynastes maculatus) B 0.01 Stripe-breasted Spinetail (Synallaxis cinnamomea) B 0.01 White-tailed Nightjar ( Caprimulgus cayennensis) H 0.01 White-throated Spadebill (Platyrinchus mystaceus) B 0.01 White-winged Becard (Pachyramphus polychopterus) B 0.01 Extinction-prone Birds of Trinidad and Tobago 191

TABLE 2 continued.

Vulnerability Species Risk factors• to extinctionb Yellow-breasted Flycatcher (Tolmomyias flaviventris) B 0.01 Yellow-legged Thrush (Platycichlajlavipes) B 0.01 Bananaquit ( Coereba jlaveola) 0.0 1 Bare-eyed Robin (Turdus nudigenis) 0.01 Blue-black Grassquit (Volatiniajacarina) 0.01 Carib Grackle (Quiscalus lugubris) 0.01 Cattle Egret (Bubulcus ibis) 0.01 Gray Kingbird (Tyrannus dominicensis) 0.01 Great Kiskadee (Pitangus sulphuratus) 0.01 Green Heron (Butorides virescens) 0.01 House Wren (Troglodytes aedon) 0.01 Shiny Cowbird (Molothrus bonariensis) 0.01 Tropical Kingbird(Tyrannus melancholicus) 0.01 Tropical Mockingbird (Mimus gilvus) 0.01 Yellow-bellied Elaenia (Elaenia flavogaster) 0.0 I •risk factors are: A) species with narrow geographic range, B) population at the edge of the species' range, C) species with only one restricted population, D) species in which population size is small, E) low population density, F) species that needs large home ranges, G) species that has large body size, H) species with low rate of reproductio11 , I) species that is not an effective disperser, J) species that migrates, K) species with specialized niche requirements, L) species that has an aggregated dispersion pattern, M) species tl1at is hunted by people bvulnerability to extinction varies from 0-1 .0 and is calculated using the categotical data on risk factors for each species in a multiple logistic regression model described in the text; species are ranked in de­ scending order of their vulnerability and the number oftisk factors they possess cpresumed extirpated

the new Conservation ofWildlife Bi11 of 1999 (Gov­ threatened cannot be rigorously defined, 1 suggest ernment of Trinidad a11d Tobago 1999), which is a for sake of discussion that it is not unreasonable to list of species I recommended based largely on assume that a species with a calculated probability whether a species was listed as extirpated or rare by of being at risk> 0 is threatened. Using these cri­ ffrench ( 1991 ). teria, there are 63 threatened species in Trinidad and 23 in Tobago. DISCUSSION The calculated vulnerability to extinction pro­ vides conservationists on Trinidad and Tobago The International Union for the Conservation with a revealing way to identify species that may be of Nature and Natural Resources has established a at risk at the island scale. l11ey inform local con­ classification system for species at risk of extinc­ servation decision makers in a way that regional tion (Groom bridge 1993). Three categories are con­ and international lists cannot. For example, IUCN's sidered to be threatened (critical, endangered and list of globally threatened species in Trinidad and vulnerable). The threatened categories should be Tobago includes only the Trinidad Piping-Guan more or less directly related to the calculated vul­ and the White-tailed Sabrewing. While these are nerabilities to extinction for birds in Trinidad and without doubt high priority species on which local Tobago. Although critetia for being considered conservationists should focus, there are many oth- 192 TEMPLE

TABLE 3. Explanatory v ari ab les that contributed sig­ analyses. W. J. Arendt, D. M. Brooks and D. C. nificantly to the logistic regression models predict­ Wege reviewed the manuscript. ing vulnerability to extinction for birds in Trinidad and Tobago, respectively. LITERATURE CITED

Regression AMERICAN ORNITHOLOGISTS' UNION. 1998. Check­ Variable coefficient Jist of North Ame1ican birds. 7th ed. American Trinidad Ornithologists' Union, Washington, DC. 829 Constant -49.54 pp. Narrow range 26.76 COLLAR, N. J., AND P. ANDREW. 1988. Birds to Small population size 16.61 watch: the ICBP world list of threatened birds. Low population density 34.21 Tech. Pub!. 8. International Council for Bird Large body size -3.08 Preservervation, Cambridge, UK. 303 pp. Narrow niche 13.76 COLLAR, N. J., L. P. GONZAGA, N. KRABBE, N. Exploited 1.52 MADRONO, L. G. NARANJO, T. A. PARKER lll, Tobago AND D. C. WEGE. 1992. Threatened birds of the Constant -4.45 Americas: the ICBP/IUCN Red Data Book. Single population 5.65 World Conservation Monitoring Centre, Cam­ Small population size 2.95 bridge, England. 1150 pp. Low population density 3.17 COLLAR, N.J., D. C. WEGE, AND A. J. LONG. 1997. Patterns and causes of endangerment in the New World avifauna. Ornithol. Monogr. 48: er species at risk of extirpation from the islands 237-260. even though they may be secure globally. Tables 1 DUI'ofN ING, J. B. (ed). 1992. CRC handbook of avian and 2 highlight many species that have not so far body masses. CRC Press, Boca Raton, FL. 371 been recognised as being at risk. At the very least, pp. these newly highlighted species might be singled FFRENCH, R. 1991. A guide to the birds of Trinidad out for censussing to reveal how rare they actually and Tobago. Cornell University Press, Ithaca, are. NY. 426 pp. The most important risk factors for birds in GASTON, K ., AND T. BLACKBURN. 1995. Birds, body Trinidad and Tobago were restricted geographic size and the threat of extinction. Phil. Trans. R. range, low population density, small population Soc. London B 347:205-212. size, large body size, narrow ecological niche, and GOVERNMENTOFTRTNTDADANDTOBAG0.1999. Con­ exploitation. In Tobago, the significant risk factors servatiOll of Wildlife Bill of 1999. Government were single population, low population density and Printing Office, Port of Spain, Trinidad. 23 pp. small population size. Such differences are interest­ GROOMBRIDGE, B. (ed). 1993. 1994 IUCN red Jist of ing, but small population size and low population threatened animals. International Union for the density are risk factors that are shared between Conservatiou of Nature and Natural Resour­ both islands. Small population size is widely recog­ ces, Gland, Switzerland. 286 pp. nised as the most biologically significant predictor MEYER DE SCHAUENSEE, R. 1970. A guide to the of extinction risk (Soule I 987). birds of South America. The Academy of Nat­ ural Sciences ofPhiladelphia, Philadelphia. 470 ACKNOWLEDGEMENTS pp. MEYER DE SCHAUENSEE, R., AND W. H. PHELPS. Without Richard £french's meticulous atten­ 1978. A guide to the birds of Venezuela. tion to life history details, this analysis of the birds Princeton University Press, Princeton, NJ. 424 of Trinidad and Tobago would have been quite pp. difficult. John Cary provided advice on statistical MORONY, J. J., W. J. BOCK, AND J. FARRAND. 1975. Extinction-prone Birds of Trinidad and Tobago 193

Reference list ofbirds of the world. American AND D. K. MOSKOVITS. 1996. N eotropical birds: Museum of Natural History, New York, NY. ecology and conservation. University of Chi­ 207 pp. cago Press, Chicago, IL. 481 pp. PETERS, R. 1983. The ecological implications of TERBORGH, J. 1974. Preservation of natural diver­ body size. Cambridge University Press, Cam­ sity: The problem of extinction-prone species. bridge, UK. 329 pp. BioScience 24:715-722. PIMM, S., H. JONES AND J. DIAMOND. 1988. On the TERBORGH, J., AND B. WiNTER. 1980. Some causes risk of extinction. A mer. Nat. 132:757-785. of extinction. Pp. 119-134 in Conservation biol­ PRIMACK, R. 1998. Essentials of conservation biol­ ogy: the science of scarcity and diversity (M. ogy. Sinauer Associates, Sunderland, MA. 608 Soule). Sinauer Associates, Sunderland, MA. pp. 608 pp. WILKINSON, L., G. BLANK AND C. GRUBER. 1996. SOULE, M. 1987. Viable populations for conser­ Desktop analysis with SYSTAT. Prentice-Hall, vation. Island Press, Washington, DC. 189 pp. Upper Saddle River, NJ. 790 pp. STOTZ, D. F., J. W. FITZPATRICK, T. A. PARKER Ill, Pp . 194-1 98 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. II, 2002.

DICKCISSELS IN TRINIDAD: NUMBERS AND IMPACTS ON RICE CROPS

GRAHAM L. WHITE1 AND STANLEY A. TEMPLE2 1Caroni Ltd., Waterloo Estate, Waterloo Road, Carapichaima, Trinidad and Tobago 2Department of Wildlife Ecology, University of Wisconsin, Madison, WJ 53706, USA

ABSTRACT.- Trinidad is at the edge of the Dickcissel's (Spiza americana) winter range, but Richard ffrench did pionee1ing research on their winter ecology in Trinidad in the 1960s. We add to information on Dickcissels in Trinidad by summarising ob­ servations of numbers and distribution over 1991-2002 and by estimating the impact that recent Dickcissel populations might l1ave on Trinidad's rice (Oryza sativa) crop, which we conclude to be minimal.

RESUMEN.-Trinidad queda a! borde de la distribuci6n invemal del Arrocero Americano (Spiza americana), pero Ri chard ffrench hizo estudios pioneros sobre su ecologia invemal en Trinidad durante Ia decada de los 1960s. Aumentamos Ia infor­ macion que se posee sobre el AJTocero Americana en Trinidad en base a las observaci­ ones sobre sus cantidades y distribuci6n durante 1991-2002 y estimamos el impacto que las actuales poblaciones del Arrocero Americano pueden tener sobre el cultivo de arroz (Oryza sativa) eu Ia Trinidad, el cual concluimos es minimo.

KEY WORDS.-crop damage, Dickcissel, ecology, Oryza sativa, dee crops, Spiza americana, Trinidad

The Dickcissel (Spiza americana) is a North METHODS American migrant found in Trinidad mainly be­ tween December and April (ffrench 1991). Richard Numbers of Dickcissels in Trinidad.-We ob­ ffrench (1967) carried out the pioneering studies of served wintering flocks of Dickcissels in Trinidad the wintering ecology of the Dickcissel at the edge during 1991 -1999. We observed and received re­ of its winter range in Trinidad, and others have ports of Dickcissels in several areas of rice cul­ since studied its winter ecology on its main tivation, including the Caroni Rice Project, Oro­ wintering range in Venezuela (e.g., Fretwell 1986, puche Lagoon and Nariva Swamp areas. Counting Basili and Temple 1995, 1998, 1999). A clear finding Dickcissels in large flocks in rice fields is difficult of all studies ofDickcissels on their winter range is because all the birds are rarely visible at the same that the birds are closely associated with rice time, except when they fly at dawn or dusk; hence ( Oryza sativa) cultivation, often being called 'rice our estimates, especially of larger flocks, are rough. birds' because of their food preference. Basili and In early 2000, Ishmaelangelo Samad (pers. Temple (1998) assessed the impact that Dickcis-sels comm.) visited Nariva Swamp on several occasions have on the extensive rice fields of Venezuela. We and was accompanied on several visits by persons follow their modelling procedure for estimating experienced in estimating flock sizes, thus provid­ consumption of rice by Dickcissels and apply it to ing a reliable estimate of the largest flock ofDick­ the situation in Trinidad, where both Dickcissels cissels in the recent past. and rice are less abundant than in Veuezuela. Estimating rice consumption by Dickcissels .-

194 Winter Ecology of Dickcissels in Trinidad 195

TABLE 1. Recent records ofDickcissels in Trinidad.

Estimated Date Location number of birds Sourceb 15 January 1991 Bush Bush not recorded GLW I 0-17 January 1993 Nariva• not recorded GLW 30 December 1994 Nariva• not recorded GLW I January 1995 Charlieville• 1 GLW 22 January 1995 Nariva• several small flocks GLW I March 1995 Craignish not recorded GLW 22 March 1995 Fishing Pond about 100 SAT 14 February 1996 Camden over 1,000 GLW 3 March 1996 Aripo Savannah 2 GLW 8 March 1996 Palmyra Village 400 GLW 13 March to 10 April 1996 Todd's Road up to 1,000-2,000 GLW 6 December 1996 Todd's Road not recorded GLW 16 December 1996 Caroni Rice Project• 4 GLW 29 January 1997 Couva about 10 GLW 27 January 1997 Brechin Castle few GLW 28 December 1997 Piarco about 500 GLW 26 January to 15 February 1998 Nariva• up to 5,000 SAT et al. 28 March 1998 Piarco 2 FEH 10-17 April1998 Trincity about 30 FER 20-29 April1998 Caroni Rice Project• up to 5,000-1 0,000 GLW et al. 4-10 February 1999 Waterloo 500 GLW 18 January 2000 McBean 200-300 GLW 2 February to 13 April 2000 Nariva• 100,000+ IS et al. 25 February to 23 March 2000 Caroni Rice Project• up to 1000 GLW et al. 4 March 2000 Waterloo 1 GLW 9-19 December 2000 Waterloo few daily GLW 2 March 2001 Maracas several large flocks BS 3-18 April 2001 Plum Mitan• thousands CR 11-14 April 2001 Caroni Rice Project" 2000 MK et al. 29 October to 7 November 2001 Caroni Rice Project" several MK 8 February 2002 Nariva• 1000 MK 25 April 2002 Caroni Rice Project" 100 MK •seen near area with rice cultivation bFEH =F. E. Hayes; MK = M. Kenefick; CR = C. Rooks; IS = I. Samad; BS = B. Sanasie, SAT= S. A. Temple; GL W =G. L. White

We followed the method of Basili and Temple sex ratio, body mass, energetic requirement, energy (1998) to estimate rice consumption. We based our content of rice) which are given in Table 2. We calculations on a Dickcissel population of 5,000- substituted a diet composition that reflects the lack 10,000 during mid-March to mid-April, the period in of sorghum (Sorghum spp.) as a food plant in which the largest numbers of Dickcissels have been T1inidad. We assumed that in Trinidad Dickcissels seen recently in Trinidad. We followed the basic substituted rice for the 18% sorghum in their diet assumptions of the Basili and Temple model (i.e., in Venezuela, resulting in a diet composition of82% I96 WHITE AND TEMPLE

TABLE 2. Estimated consumption of rice by 5,000-1 0,000 Dickcissels, mid-March to mid-April.

Variable Male Female Sex ratio(%) 60 40 Daily energy requirement per hyperphagic bird (kj) 109.70 95.08 Percent rice in diet 82 82 Rice consumption per bird per day (dry weight in g)" 8.75 7.58 Rice consumption per bird per day (fresh weight in g)b 10.41 9.03 Rice consumption per bird mid-March to mid-April (g fresh weight) 312.3 270.9 Total rice consumption by 5,000-10,000 birds (kg fresh weight) 1,479-2,957 (both sexes) Weight of paddy (kgt I,9I9-3,791 (both sexes) "based on metabolizable energy of 12.54 kj per gram of dry rice bbased on 16% moisture content in fresh rice

• Aripo Savannah . .. ~ Ca~andeC:.. U o Rice Growing Areas qe':l • Todd's Caltoo Trace/1 Trinidad Land use map 1970 Road "..- f • Caroni Rice Project ", \ L.._J ~ Nariva Swar,np __,d)

• Craignish Village St. Madeleine Oropouche Lagoon ' r;s:...--"'';)/.# p ,..,

FIG. 1. Rice growing areas in Trinidad and locations of Dickcissel observations.

area. I11 the 1960s, attempts to improve drainage from the Nariva Swamp following disputes over and irrigation Jed to an infiltration of saline waters land tenure and were allocated part of the Caroni into the lagoon. Petroleum extraction and associ­ Rice Project. At present there is little rice culti­ ated activities caused saline conditions to develop vation in the Oropouche Lagoon, Kernahan Trace in areas not reached by seawater (S. Persad pers. or the Cacandee area. There are, however, large comm.). Degradation of the soil was such that by areas of volunteer rice at Caltoo trace (G. White little rice cultivation remained in the Oropouche pers. obs.). Current(2000) production nationally) is area by 1974, and sedges replaced grasses in the expected to be roughly 6000 tonnes, produced more saline areas. Farmers either switched to cul­ mostly in the Caroni area (Q. Cabralis pers. comm.) tivating sugarcane or moved out (S. Persad pers. Now that Dickcissels may be returning to Trini­ comm). Many rice farmers relocated to Nariva dad in larger numbers than in recent decades, con­ Swamp after Kernahan trace was constructed in cerns about their impact on local rice have emerged. 1974. The Caroni Rice Project, where large flocks of birds By 1982 production had declined to just 1043 were observed, encompasses 1,028 planted ha, and ha (Anonymous 1986). Production revived in the an adjacent 320 ha of rice are under other owner­ 1980s, with production increasing from 400 tonnes ship. Our calculations of rice consumption by Dick­ paddy in 1984 to a record 22,000 tonnes in 1992 cissels in 1998, the year of maximum recent abun­ (Anonymous 1998). This was due to the Caroni dance, suggests that Dickcissels are a relatively Rice Project and large farmers in the Nariva area. minor threat to rice crops. Their consumption in Since then the large farmers have been displaced 1998 was less than the typical yield from 1 ha (i.e., 198 WHITE AND TEMPLE

3,000 kg/ha). We therefore recommend that these mary of results. Central Statistical Office, Port losses be tolerated and that no attempts at con­ of Spain, Publication no. 6. trolling Dickcissels be undertaken unless numbers ANONYMOUS. 1986. 1982 Agricultural census. Cen­ of Dickcissels increase, or they become more regu­ tral Statistical Office, Port of Spain. lar. The effect of the very large flock at Nariva on ANONYMOUS. 1998. Quarterly agricultural report, surrounding rice lands was not ascertained. There January-June 1998. Central Statistical Office, were, however, large areas of volunteer rice at the Ministry of Planning and Development, Port of nearby Caltoo Trace rice farms where land tenure Spain. was in dispute. If it is ever deemed necessary to BASIL!, G., AND S. A. TEMPLE. 1995. A perilous protect 1ice crops from Dickcissels, we recommend migration. Nat. Hist. 9:40-47. that non-lethal methods (repellants and strategic BASIL!, G., AND S. A. TEMPLE. 1998. Dickcissels and scheduling of planting and harvesting to avoid crop damage in Venezuela: defining the prob­ overlapping with Dickcissel visits) be employed. lem with ecological models. Ecol. Applic. 9:732- 739. ACKNOWLEDGEMENTS BASlLI, G. D., AND S. A. TEMPLE. 1999. Winter ecology, behavior, and conservation needs of We thank G. Basili and J. Zimmerman for Dickcissels in Venezuela. Stud. Avian Bioi., reviewing the manuscript, F. E. Hayes, M . Kenefick, 19:289-299. J. S. Kenny, C. Rooks, I. Samad and B. Sanasie for FFRENCH, R. P. 1967.111e Dickcissel on its wintering contributing observations, and S. Persad and Q. grounds in Trinidad. Living Bird 6:123-140. Cabralis for discussion. FFRENCH, R. P. 1991. A guide to the birds of Trini­ dad and Tobago. Cornell University Press, LITERATURE CITED Ithaca, New York. 426 pp. FRETWELL, S. 1986. Distribution and abundance of ANONYMOUS. 1969. Agricultural census 1963, sum- the Dickcissel. Curr. Omithol. 4:211-242. Short Communications 199

Pp. 199-200 in Studies in Trinidad and Tobago Omithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. II, 2002.

FIRST SIGHT RECORD OF GREY HERON (ARDEA CINEREA) FOR TOBAGO

DAVIS W. FINCH 91 South Road, East Kingston, NH 03827, USA

TI1e Grey Heron (Ardea cinerea) is a Eurasian darker grey sides, wing linings and remiges. The species that has occurred as a vagrant in Montser­ foreneck was narrowly white with a ragged border rat, Martinique, Barbados, Trinidad, French Guiana of short and strikingly black lines, these extending and Amazonian Brazil (American Ornithologists' sparsely onto the sides of the white belly. The Union 1998). The Trinidad bird was banded in thighs were white and the legs dark brown, yellow­ France the previous year (ffrench 1991) and the ish olive on the inside. Brazilian bird was banded in France the same year TI1is sight record has been accepted by the (Sick 1993). In this note I report the first sight Trinidad and Tobago Rare Bird Committee (White record of this species for Tobago, West Indies. and Hayes 2002). Sight record.-During 15-17 January 1999, a Discussion.-In a 2 hr period on 17 January, we first-winter Grey Heron frequented the east lagoon were able to study this bird as well as the two other at the Bon Accord W ASA sewage treatment facil­ members of the superspecies: an immature Great ity, where it was easily studied in the company of a Blue Heron (A. herodias) at nearby Buccoo Marsh number of other heron species. Five of us (a and an adult Cocoi Heron (A. cocoi) at Courland WINGS tour including myself plus Joan Butt, Val­ River. We noted differences in their proportions, erie Knowles, Lin Watson and Patricia Lalor, all both appearing longer in the bi1I, neck and legs and familiar with the species in Britain) scrutinised it 011 more massive overall than the Grey Heron, and in several occasions with a Questar telescope. We their plumage as well, the Great Blue Heron being noted the absence of wmm t011es anywhere in the extensively washed with rusty tones, especially in bird's plumage, which appeared grey, black and the area of the shoulders, and the Cocoi appearing wl1ite throughout, and its relatively small size. starkly black and white. When fishing from a low concrete wall dividing the Birders and ornithologists should be alert for lagoon it was often within 10 m of a Great Egret this species in the Caribbean and northeastern (Ardea alba), allowing a direct comparison in size; South America. For further information on distin­ the Grey Heron was shorter in the bill, neck and guishing Grey and Great Blue Heron, see Gantlett legs and perhaps I 0% less bulky overall. The bill (1998) and Lethaby and McLaren (2002). was orange on the outer third of both maxilla and Acknowledgements.-1 thank M. Frost, J. Kush­ mandible, pale yellow basally, and dark on the ridge Ian and E. Massiah for reviewing the manuscript. of the culmen. A triangle of light grey extended rearward from the top of the bill over the crown, LITERATURE CITED narrowing to a point, and the remainder of the head was white, including eyebrow, cheeks, chin and AMERICAN ORNITHOLOGISTS' UNION. 1998. Check­ throat, while the unfeathered !ores graded from list of North American birds. 7th ed. American greenish to lemon yellow, and the eye was yellow. Ornithologists' Union, Washington, DC. 829 The entire dorsum and sides of the neck were a pp. pure, smooth, uniform grey, all of one tone and FFRENCH, R. 1991. A guide to the birds of Trinidad without the slightest hint of rust, olive or brown. and Tobago. 2nd ed. Cornell University Press, When the bird flew short distances or momentarily Ithaca, NY. 426 pp. balanced on the wall with wings raised, it revealed GANTLETT, S. 1998. Identification of Great Blue 200 Short Communications

Heron and Grey Heron. Birding World 11:12- pp. 20. WHITE, G., AND F. E. HAYES. 2002. Second report of LETHABY, N., AND I. A. MCLAREN. 2002. The iden­ the Trinidad and Tobago Rare Bird Committee. tification of Gray Heron. Birding 34:24-33. Living World (J. Trin. Tob. Field Nat. Club) SICK. H. 1993. Birds in Brazil: a natural history. 2002:in press. Princeton University Press, Princeton, NJ. 703

P. 200 in Studies in Trinidad and Tobago Omithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci ., Univ. West Indies, St. Augustine, Occ. Pap. 11 , 2002.

KLEPTOPARASITISM OF A GREAT EGRET (ARDEA ALBA) BY A COMMON BLACK-HAWK (BUTEOGALLUS ANTHRACINUS)

GEOFFREY GOMES Apt. 8, Lady Chancellor Apts., Lady Chancellor Hill, Port ofSpain, Trinidad and Tobago

Kleptoparasitism, the interspecific and intra­ tl1ird attempt. I am also uncertain whether the same specific stealing of already procured food, has been Great Egret was robbed on each occasion. In each reported for many species of raptors, particularly instance the egret did not attempt to defend itself. those that are omnivorous or feed on carrion (e.g., Acknowledgements.-I thank J. V. Remsen, Jr., Brown and Amadon 1989, Brockmann and Barnard and G. L. White for reviewing this note, and F. E. 1979). The Common Black-Hawk (Buteogallus an­ Hayes for providing pertinent literature. thracinus) is known to feed on a variety of arthro­ pods and small vertebrates (Brown and Amadon LITERATURE CITED 1968, Palmer 1988, Jolmsgard 1990, Schnel11994).ln this note I report the first instance of kleptopara­ BROCKMANN, H. J., AND C. J. BARNARD. 1979. sitism in this species. Kleptoparasitism in birds. Anim. Behav. 27: In the morning of 10 May 1998, I observed a 487-519. Common Black-Hawk standing on a patch of grass BROWN, L., AND D. AMADON. 1989. Eagles, hawks adjacent to a rice field at Caroni, Trinidad. Sud­ and falcons of the world. Wellfleet Press, Se­ denly the hawk flew toward a flock of Great Egrets caucus, NJ. 945 pp. (Ardea alba), Snowy Egrets (Egretta thula) and JOHNSGARD, P. A. 1990. Hawks, eagles, & falcons Cattle Egrets (Bubulcus ibis) about 25m away, and of North America: biology and natural history. landed about 1 m in front of a foraging Great Egret Smithsonian Institution Press, Washington, The Great Egret dropped an unidentified frog which DC. 403 pp. it had just caught, and stepped backward. The PALMER,R. S. (ed.). 1988. Handbook of North Am­ hawk stepped forward and collected the frog in its erican birds. Vol. 4. Yale University Press, New talons, carried it to another field and ate it. Twice Haven, CT. 433 pp. more the hawk robbed a Great Egret in a similar SCHNELL, J. H. 1994. Common Black-Hawk Buteo­ manner withi11 the next 2 hr, though I was unable to gallus anthracinus. Birds N. Amer. 122:1-19. determine whether the hawk was successful on the Short Communications 201

Pp. 201-203 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, cds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. 11, 2002 .

FIRST OCCURRENCES OF FRANKLIN'S GULL (LARUS PIPIXCAN) FOR TRINIDAD

1 2 DOUGLAS B. MCNAIR , FLOYD E. HAYES AND GRAHAM L. WHITE3 1Tall Timbers Research Station, 13093 Henry Beadel Drive, Tallahassee, FL 32312-9712, USA 2Department ofLife Sciences, University ofthe West Indies, St. Augustine, Trinidad and Tobago 3c/o Caroni Research Station, Waterloo Road, Trinidad and Tobago

Franklin's Gull (Larus pipixcan) breeds in the brand) studied another immature standing on mud­ interior of western Nortl1 America and winters pri­ flats among about 2500 Laughing Gulls at Water­ marily along the west coast of South America loo, 19 km south of Port of Spain. The observers (Clapp eta!. 1983 , Burger and Gochfeld 1994). Des­ failed to see missing secondary feathers, suggest­ pite having a narrow migration corridor, Franklin's ing the bird was a different individual from that Gull is a noted wanderer, having been reported as observed at Port of Spain. The gull was studied far away, for example, as South Africa (Clapp et al. through telescopes from as close as 100 m from 1983, Cramp and Simmons 1983, Hoogendoorn and I 540-16 I 0 hr. In addition to the above field marks, Steinhaus 1989, Burger and Gochfeld 1994). In the it was noted that in comparison with nearby Laugh­ northern and eastemCaribbean, Franklin's Gull has ing Gulls, the wl1ite crescents surrounding the eyes been reported from Cuba, Hispaniola, Puerto Rico, were broader, the bill was distinctly shorter, and the and St. Barthelemy (Dwight 1925, Buckley and legs appeared shorter. The observers were unable Buckley 1970, Hoogendoom and Steinhaus I989, to obtain clear views of the white outer rectrices Burger and Gochfeld 1994, Raffaele et al. 1998; A. typical of immature Franklin's Gull. The body of the Kirkconnellfide A. Keith and G. Wallace) and veri­ Franklin's Gull appeared about equal in size to fied (photographs) in Guadeloupe (Feldmann eta]. Laughing Gull. 1999). In northeastern South America, Franklin's At Waterloo, from one to two first-winter Gu11 has been reported from French Guiana (Tostain Franklin's Gulls were seen among Laughing Gulls and Dujardin 1989). In this note we document the by GW and FER later in February: on 8 (one), 10 first occurrences (verified records and sight re­ (two), 12 (two), 13 (one) and 26 February(one). On ports) ofFranklin's Gul1 for Trinidad. 14 and 20 March, GW found an adult Franklin's Sight reports.-On 5 January I999, D. B. Mc­ Gull in non-breeding plumage. It was observed Nair (DBM) and F. E. Hayes (FEH) observed a through a telescope as close as 70 m from 0800- first-winter Frank! in's Gull flying back and forth be­ 0900 hr on 14 March and from a boat at 40 m on 20 side the boat docks at Port of Spain. The gull was March. In addition to characteristics shared by im­ observed through binoculars from a distance of200 matures and adults (e.g., short bill), the adult had a m from 1535-1545 hr. It was identified by its dark black bill with a red tip, white forehead with thin half-hood on the crown, white collar, lighter upper­ dark streaks, an all-white tail, white 'windows' side of wings, clean white m1derparts, dark subter­ between the black wing tips and the rest of the minal tail band, and notably smaller wing-span and upperside of the wing, greyer upperside of the more buoyant flight in comparison with several wings compared to Laughing Gull, and small black nearby first-winter Laughing Gulls (L. atricilla). wing tips without extensive areas of grey or black The symmetry of several missing secondaries on on the underside of the primaries. both wings suggested the bird was moulting. These sight reports have been accepted by the On 7 February 1999, FEH, G. White (GW) and Trinidad and Tobago Rare Bird Committee (White a group of Swedish birders (led by Staffan Rode- and Hayes 2002). 202 Short Communications

FIG. I. First-winter Franklin's Gull at San Fernando, Trinidad, 9 December 2000. Photo by F. E. Hayes.

FIG. 2. Adult Franklin's Gull at San Fernando, Verified records.-On 3 December 2000, GW Trinidad, I 0 November 2001 . Photo by F. E. Hayes. found a first-winter immature Franklin's Gull among 1800 Laughing Gulls at Waterloo. The following day, 4 December 2000, it was relocated by Martyn first-winter birds, including a dead immature that Kenefick (pers. comm.), but not observed subse­ was salvaged; TTRS 3958) at Apalachicola, Frank­ quently at Waterloo. However, what may have lin County, Flmida. In southeastern North America, been the same individual was relocated and photo­ the Franklin's Gull is usually a rare migrant and graphed (Fig. 1) by FEH at San Femando, c. 25 km more numerous on the Gulf than Atlantic coast to the south, on 9 December 2000. Subsequently (Clapp et al. 1983). one or two first-winter immatures were seen repeat­ Despite the apparent rarity of Franklin's Gull in edly at San Fernando on 12 December 2000 (FEH), the Caribbean and northeastem South America, we 21 January2001 (FEH), 22 January2001 (two byM. agree with Buckley and Buckley (1970) that it Kenefick), 27 January2001 (FEH), 29 January 2001 probably occurs more often in the Caribbean (and (H. Kilpatrick), 10 February2001 (FEH)and22 April northeastem South America) than the few reports 2001 (M. Kenefick et al.). suggest, at least in some years. We believe it is On I 0 November 2001, an adult Franklin's Gull most likely that Franklin's Gulls observed in Trin­ moulting into basic plumage was found among I 000 idad in winter 1999 came directly from southeastem Laughing Gulls was pl10tographed (Fig. 2) by FEH North America, after an unusually large incursion at San Fernando. It was relocated by FEH on 17 to this region, rather than coastwise along north em November 2001 but not seen subsequently. South America. Discussion.-In the aftermath of an enormous Franklin 's Gull has been reported once from stonn moving northeastward across the central Amba (Hoogendoom and Steinhaus 1990), but United States during the second week of November never from Venezuela or the Cmibbean coast of 1998, an unusually large incursion of Franklin's Colombia during autumn (Burger and Gochfeld Gulls occurred in eastern North America and 1994). A long-distance passage to Trinidad from showed a greater Atlantic coastal component than southeastem North America would be consistent typical (Bri11kley 1999). Appearing first in the Great with the pattern of Franklin's Gull long-distance Lakes region and in the northeastern United States, migration offshore in autumn from Mexico to their the gulls steadily moved southward during the main winter range in coastal Peru and Chile (Burger succeeding weeks, lingering into early December as and Gochfeld 1994). Subsequent occunences in far north as New Jersey. The invasion into south­ 2000 and 2001 also indicate that vagrancy ofFrank­ eastern North America, which included the Flotida lin's Gull probably occurs in Trinidad in the ab­ peninsula (e.g., Pranty 1999a, b), persisted into sence of such storm activity, suggesting that they December. As late as 25 December 1998, DBM may have been overlooked before. Omitho1ogists observed six Fra11klin 's Gulls (an adult and five should be alert for Franklin's Gull in the southern Short Communications 203

Caribbean, and search for it among flocks of Laugh­ Wildlife Service, Office ofBiological Services, ing Gulls. Washington, DC. 853 pp. Acknowledgements.-A grant from the Univer­ CRAMP, S., AND K. E. L. S1\1MONS (EDS.). 1983. The sity of the West Indies (to FEH) for studying birds birds of the western Palearctic. VoL 3. Waders in Venezuela enabled DBM and FEH to be at the to gulls. Oxford University Press, Oxford. 913 Pori of Spain docks on 5 January 1999. We thank pp. A. Keith and G. Wallace for supplying information DWIGHT, J. 1925. The gulls (Laridae) of the world: about the recent reports of Franklin's Gulls by A. their plumages, moults, variations, relation­ Kirkconnell in Cuba, and A. Keith for supplying ships and distribution. BulL Amer. Mus. Nat. information on an older report by W. l Arendt in Hist. 52:63-402. the Dominican Republic. We thank P. A. Buckley FELDMANN, P., E. BENITO-ESPINAL, AND A. R. KEITH. and M. Gochfeld for reviev.ring this note, and M. 1999. New bird records from Guadeloupe and Kenefick and H. Kilpatrick for sharing their ob­ Martinique, West Indies. l Field Ornithol. servations. 70:80-94. HOOGENDOORN, W., AND G. H. STEINHAUS. 1990. LITERATURE CITED Nearctic gulls in the western Palearctic. Dutch Birding 12:109-164. BRINKLEY, E. S. 1999. Changing seasons: fall mi­ PRANTY, B. 1999a. Field observations. Fall report: gration. North A mer. Birds 53:12-19. August to November 1998. Florida Field Nat. BUCKLEY,P.A.,AND F. G. BUCKLEY. 1970. Notes on 27:62-75. the distribution of some Puerto Rican birds PRANTY, B. 1999b. Field observations. Winter re­ and on the courtship behavior of White-tailed port: December 1998-February 1999. Florida Tropicbirds. Condor 72:483-486. Field Nat. 27:130-140. BURGER, J., AND M. GOCHFELD. 1994. Franklin's Gull RAFFAELE, H., J. WILEY, 0. GARRIDO, A. KEITH, AND (Larus pipixcan). In The birds of North Amer­ J RAFFAELE. 1998. A guide to the birds of the ica, no. 116 (A. Poole and F. Gill, eds.). Acad­ West Indies. Princeton University Press, emy of Natural Sciences, Philadelphia, and Princeton, NJ. 511 pp. American Ornithologists' Union, Washington, TOSTAIN, 0., AND J.-L. OUJARDlN. 1989. Mise en DC. 28 pp. place d'une aire d'hivernage neotropicale de CLAPP, R. B., D. MORGAN-JACOBS, AND R. C. BANKS. larides holarctiques: Larus pipixcan, Larus 1983. Marine birds of the southeastern United ridibundus, et Larus fuscus. Alauda 57:189- States and Gulf of Mexico. Part III: Charad­ 215. riiformes. FWS/OBS-83/30. U. S. Fish and 204 Short Communications

Pp . 204-206 in Studies in Trinidad and Tobago Ornithology Honouring Richard ffrench (F. E. Hayes and S. A. Temple, eds.). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. I 1, 2002.

NOTEWORTHY BIRD RECORDS FOR TRINIDAD AND TOBAGO, INCLUDING FIRST REPORTS OF WOOD SANDPIPER (TRINGA GLAREOLA) AND WHITE-EYED VIREO (VIREO GRISEUS)

WAYNE R. PETERSEN 1 AND DOUG MCRAE2 1Massachusetts Audubon Society, Center for Biological Conservation, South Great Road, Lincoln, MA 0177 3, USA 2Box 3010, Brighton, Ontario KOK JHO. Canada

The explosive increase in the number of birders from the Antilles" (American Omithologists' Union and birding tour groups visiting Trinidad and 1998) and are considered as "vagrants in the West Tobago since the publication of Richard ffrench's Indies" (Raffaele et al. 1998). (1973, 1991) field guide has produced a number of Swainson's Hawk (Buteo swainsoni).-We new distribution records. Here we describe note­ (DMcR, WRP et al.) observed and photographed wmihy records for six species, including two an adult light-morph i11dividual for more than an species new for the country: Wood Sandpiper hour over Little Tobago, off eastem Tobago, on 31 (Tringa glareola) and Wl1ite-eyed (Vireo griseus). December 1996. Although this long-distance mi­ Cory's Shearwater (Calonectris diomedea). grant regularly travels to Argentina and Uruguay -No fewer than I 5 individuals were carefully ob­ for the winter, it is virtually unknown in the served by WRP et a1. within 500 m of Manzanilla Caribbean, the only previous records being "a Beach, east coast of Trinidad, on 30 December report from Jamaica [that is] highly questionable" 1991. This apparently represents the first observa­ (American Ornithologists' Union 1998) and a tion of healthy individuals of this species for Trin­ sighting from the Dominican Republic on 22 April idad. Previous records in June 1955, February 1956, 1996 (Bradsl1aw eta!. 1997). However, there are two and April 1961 involved single specimens found previous records of adults seen at Little Tobago on dead or moribund on Manzanilla and Mayaro 27 January 1989 and 22 March 1990 (ffrench 1991), beaches (Collins 1969, ffrench 1991). Although possibly referring to the same individual. Cory's Shearwater is possibly more frequent off­ Wood Sandpiper (Tringa glareola) .--Dn 30 shore than records would suggest, encountering December 1996, we (DMcR, WRP eta!.) noted an such unprecedented numbers in close proximity to odd shorebird at Buccoo Swamp, Tobago. Stand­ Trinidad, or anywhere else so near the northern ing amidst a Solitary Sandpiper (T solitaria) and coast of South America, is most unusual (American several Lesser Yellowlegs (Tjlavipes) and Greater Ornithologists' Union 1998). Yellowlegs (T melanoleuca), it was clearly a Trin­ Black Vulture (Coragyps atratus).-A Black ga by shape. The sandpiper resembled a chunky Vulture well observed by WRP low overhead near Lesser Yellowlegs with a prominent whitish super­ Crown Point, Tobago, on 2 January 1992, was ap­ cilium; upperparts, secondary coverts and tertials parently one of very few such reports for the is­ that were conspicuously checkered with creamy­ land. ffrench ( 1991) suggested that all previous white; and a distinct wa1m-brown wash across the reports pertained to surviving birds released from breast of the otherwise light grey underparts. The captivity during the making of a movie in 1959, the bill was straight and was approximately the same last of which was observed at Little Tobago in length as the head; the legs were dull greenish and 1972. Despite the abundance of this species in were proportionately shorter than those of nearby nearby Trinidad (visible from Tobago) and Ven­ Lesser Yellowlegs. In flight, the sandpiper dis­ ezuela, Black Vultures are "questionably reported played light grey underwings and a white tail that Short Communications 205 was heavily marked with fine dusky barring. Al­ during the period of observation. though the bird possessed a thin eye ring, it lacked The vireo was subsequently relocated by F. E. the spectacled effect characteristic of a Solitary Hayes et al. (pers. comm.) on 4 January and 9 Feb­ Sandpiper. During several occasions when the bird ruary 1998, and by D. W. Finch (pers. comm.) on 20 flew, it gave a series of four or five sharp vocali­ January 1998. The following winter a white-eyed sations, less shrill than the corresponding calls of adult, presumably the same individual, was found a Solitary Sandpiper and somewhat more reminis­ at the same locality by R. Neckles (F. E. Hayes pers. cent of those of a Lesser Yeltowlegs. Based on the comm.) on 28 January 1999. freshness of the plumage and the clarity and ex­ This report is the first for Trinidad and Tobago tensiveness of the creamy spotting on the tertia! and the Caribbean south and east of the Greater edges and secondary coverts, the bird was judged Antilles and St. John, U. S. Virgin Islands (Am­ to be an immature in first-winter plumage (Hayman erican Ornithologists' Union 1998, Raffaele et al. et al. 1986). 1998). A fine series of definitive colour photographs Cape May Warbler (Dendroica trigina).-We was obtained by Peggy Keller. The bird apparently found an unmistakable adult male in winter plumage remained at this locality through the winter, where in casuarina trees (Casuarina equisetifolia; family it was seen by D. W. Finch (pers. comm.) and his Casuarinaceae) adjacent to the Trincity Sewage Wings tour group on 18 January 1997 and by F. E. Ponds, Trinidad, on 31 December 1998. It was sub­ Hayes et a!. (pers. comm.) on 27 February 1997. sequently seen by many observers up until 8 April This observation provides the first record for 1998 (by H. J. Lehto; F. E. Hayes pers. comm.). This T1inidad and Tobago. Although small numbers of observation represents only the second for Trini­ this wide-ranging Palearctic shorebird are regularly dad; the first was noted at Nariva on 16 February recorded in the Aleutian Islands, on islands in the (no year given; ffrench 1973, 1991). This species Bering Sea, and rarely breeding in western Alaska, has been described as casual on Tobago and Trini­ there are only two documented records for eastern dad, the Netherlands Antilles, and the islands off North America, both in New York (I 907 and I 990; Colombia and Venezuela (Dunn and Garrett 1997, Levine 1998), and a record from Bermuda (Amos American Ornithologists' Union 1998) and as a and Wingate 1983). In the Caribbean region, the scarce winter visitor to Tobago (ffrench 1996). Wood Sandpiper has been recorded at Barbados Details of all records have been submitted to on several occasions (Raffaele et al. 1998), but has the Trinidad and Tobago Rare Bird Committee. never been documented in South America. As may be the case for several other Palearctic vagrants ACK010WLEDGEMENTS that have occurred in Barbados, it is likely that this species reached Tobago while in passage to Africa. We thank D. W. Finch and A. Keith for re­ White-eyed Vireo (Vireo griseus).-We(DMcR, viewing the manuscript. We also thank the partici­ WRP et al.) discovered a White-eyed Vireo in a pants of our Field Guides tours for making our trips small coppice of mangroves and other thorny veg­ possible, and our local guides, J. Ramlal on Trin­ etation at Buccoo, Tobago, on 2 January 1998. It idad and A. James on Tobago, who shared our was olive on the back with a greyish cap that observations. co11trasted slightly with the olive colouration of the back, and it possessed two distinct whitish wing LITERATURE CITED bars, a white throat and underparts, distinctly yellowish flanks, and prominent yellowish specta­ AMOS, E. J. R., AND D. B. WINGATE. 1983. First cles. The eyes were dark, suggesting that the bird record of Wood Sandpiper, Tringa glareola, was a hatching year individual in its first-winter from Be1muda. Amer. Birds 37:115-116. plumage. The bird was observed closely enough to AMERICAN ORNITHOLOGISTS' UNION. 1998. Check­ see the tiny hook at the end of its bill which is list ofNorth American Birds. 7th ed. American characteristic of all vireos. At no time did it vocalize Ornithologists' Union, Washington, D.C. 829 206 Short Communications

pp. fl'RENCH, R. 1991. A guide to the birds of Trinidad BRADSHAW, c. G., G. M. KIRWAN, AND R. S. R. and Tobago. 2nd ed. Cornell University Press, WILLIAMS. 1997. First record of Swainson's Ithaca, NY. 426 pp. Hawk Buteo swainsoni for the West Indies. HAYMAN, P., J. MARCHANT, AND T. PRATER. 1986. Bull. Brit. Omithol. Club 117:315-316. Shorebirds: an identification guide to the wa­ COLLINS, C. T. 1969. A review of the shearwater ders of the world. Houghton Mifflin Co., Bos­ records for Trinidad and Tobago, West Indies. ton, MA. 412 pp. Ibis Ill :251 -253 . LEVINE, E. (ED.) . 1998. Bull's birds of New York DUNN, J. L. AND K. L. GARRETf. 1997. A field guide state. Cornell University Press, Ithaca, NY. 622 to warblers ofNorth America. Houghton Mif­ pp. flin Co., Boston, MA. 656 pp. RAFFAELE, H., J. WILEY, 0. GARRIDO, A. KEITH, AND FFRENCH, R. 1973. A guide to the birds of Trinidad J. RAFFAELE. 1998. A guide to the birds of the and Tobago. Livingston Publishing Company, West Indies. Princeton University Press, Wynnewood, PA. 470 pp. Princeton, NJ. 511 pp.

Pp. 206-207 in Studies in Trinidad and Tobago Ornithology Honouring Richard [french (F. E. Hayes and S. A. Temple, eds .). Dept. Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. 11,2002.

FIRST SIGHT RECORD OF SLATY ELAENIA (ELAENIA STREPERA) FOR TRINIDAD

COURTENAY ROOKS 1 AND EDWARD ROOKS2 1Paria Springs Trust, Pole 21, Gomez Trace, Brasso Seco, Faria, Trinidad and Tobago 24919 Brewster Avenue, San Jose, CA 95124-5448, USA

Several species of flycatchers that breed in Elaenia for Trinidad. southern South America and migrate n01thward Sight record.-At about 1700 on 21 July 1998, during the non-breeding season have been recor­ we noted an unfamiliar Elaenia sp. repeatedly for­ ded in Trinidad, including the Small-billed Elaenia aging on the fruit of a Trema micranthurn (Ulma­ (Elaenia panlirostris), Swains on's Flycatcher (My­ ceae) tree at Paria Springs, Trinidad. We took notes iarchus swainsoni), Variegated Flycatcher (Empi­ while viewing the bird through 1Ox 50 binoculars donomus varius) and Fork-tailed Flycatcher (Tyran­ and a 15-45x zoom Nikon telescope from as close as nus savana; ffrench 1991 ). Such birds are referred 10 m. Its size was roughly equivalent to that of a to as Neotropical (sensu Hayes 1995) or austral Tropical Pewee (Contopus cinereus). We noted a (sensu Chesser 1994) migrants. The Slaty Elaenia sma1l, dark bill with a pinkish base, a pale yellowish (Elaenia strepera) is also a Neotropical migrant eye ring, and a small crest that was not raised. The that breeds on the east slope of the Andes in upperparts were uniformly grey, with two huffy northwestern Argentina and southern Bolivia, and wing bars and buffy edges to the flight feathers. migrates as far north as Colombia and north-eastern The upper breast was grey and the remaining Venezuela {Marantz and Remsen 1991 , Ridgely and underparts were white, with a distinct border be­ Tudor 1994). Its wintering distribution is poorly tween the grey and white areas. The legs were dark, known, but may be limited to hilly areas in north­ and the tail dark grey. We observed the bird until eastem Venezuela (Marantz and Remsen 1991). In about 1830, and again on 22 July from about 0800- this note we report the first sight record of Slaty 0900. Subsequent efforts to relocate the bird were Short Communications 207 unsuccessful. The tree was located in secondary Marantz and T. S. Schulenberg for reviewing an forest about I 0 m from an area cleared by lawn­ earlier draft of this note. Y. Baksh-Comeau and V. C. mowers, and about 70 m from lower montane rain­ Quesnel assisted in the identification of the tree. forest at an elevation of roughly 300 m. Our field notes, which include a sketch, were submitted to LITERATURE CITED the Trinidad and Tobago Rare Bird Committee and subsequently accepted (White and Hayes 2002). CHESSER, R. T. 1994. Migration in South America: Discussion.-The distinctly grey colouration an overview of the austral system. Bird Con­ and small size distinguishes this species from other serv. lnt. 4:91-107. potential flycatcher species in Trinidad. 1l1e Slaty CHESSER, R. T. 1997. Patterns of seasonal and Elaenia most closely resembles the Gray Elaenia geographical distribution of austral migrant (Myiopagis caniceps) and Sui1iri Flycatcher flycatchers (Tyrannidae) in Bolivia. Omithol. (Suiriri suiriri) of South America (Ridgely and Monogr. 48:171-204. Tudor 1994). Botl1 of these species were regarded FFRENCH, R. 1991. A guide to the birds of Trinidad as austral migrants by Cl1esser ( 1994, 1997), but and Tobago. 2nd ed. Cornell University Press, neither is known to migrate long distances to Ithaca, NY. 426 pp. northern South America (Ridgely and Tudor 1994, HAYES, F. E. 1995. Definitions for migrant birds: R. T. Chesser pers. comm.). The buffy wing bars what is a Neotropical migrant? Auk 112:521- and edges to the flight feathers suggest the bird 523. was a female, though we did not note an olive tinge MARANTZ, C. A., AND J. V. REMSEN, JR. 1991. on the upperparts (Ridgely and Tudor 1994), or an Seasonal distribution of the Slaty Elaenia, a immature male retaining juvenile wing coverts (C. little-known austral migrant of South America. A. Marantz and T. Schulenberg pers. comm.). J. Field Ornithol. 62: 162-172. Marantz and Remsen (1991) reported six specimen PAYNTER, R. A., JR. 1982. Omithological gazetteer records from Venezuela between the dates of9 May of Venezuela. Museum of Comparative Zool­ and 13 July; the nearest to Trinidad was from ogy, Harvard University, Cambridge, MA. 245 Macuro (formerly Cristobal Colon; Paynter I 982), pp. Sucre, in the Pari a Peninsula of Venezuela, roughly RIDGELY, R. S., AND G. TUDOR. 1994. The birds of 75 km from our sighting. The Slaty Elaenia ap­ South America. Volume 11 . The suboscine pas­ parently represents a rare visitor to Trinidad during serines. University of Texas Press, Austin, TX. the austral winter, and should be searched for by 814 pp. birders and ornithologists. WHITE, G.,ANDF. E. HAYES. 2002. Second report of Acknowledgements.-E. Rooks thanks Santa the Trinidad and Tobago Rare Bird Committee. Clara University's lntemational Programs for send­ Living World (J. Trin. Tob. Field Nat. Club) ing him to Trinidad. We tl1ank R. T. Chesser, C. A. 2002:in press. 208 Short Communications

Pp. 208-209 in Studies in Trinidad and Tobago Omithology Honouring Richard [french (F. E. Hayes and S. A. Temple, cd s.). Dept Life Sci., Univ. West Indies, St. Augustine, Occ. Pap. 11, 2002.

POTENTIAL MORTALITY OF BIRDS DUE TO ENTANGLEMENT IN THE GRASS PHARUS LATIFOLIUS

GRAHAM L. WHITE c/o Caroni Research Station, Waterloo Rd., Carapichaima, Trinidad and Tobago

Entanglement is considered a minor cause of distribution of its seeds as the panicles cling to any bird mortality. Of 1290 kno\VTI causes of bird mor­ skin or clothing of passing l1ikers. talityexaminedbyLincoln(l931), I 1 cases(0.85%) On the trail leading to Soho Cave in Aripo were classified as entanglement in string or nest­ Valley, Trinidad(Comeauetal.l992),P. latifoliusis ing material, but no mention was made of entangle­ abundant. During a trip to the cave in 1992, I no­ ment in plant fruiting bodies.ln North America, the ticed that a Green Hermit (Phaethornis guy) had the flower heads of the common burdock (Arctium become trapped by a panicle of the grass. TI1e bird minus) have snared at ]east 12 species of small was alive but lying on the forest floor, so I disen­ birds (McNichol11988), whose mean weight rm1ges ta11 gled and released it. Within the next 300 m I from 3.15 gin the Ruby-throated Hummingbird found a Bananaquit (Coerebaflaveola) in the grips (Archilochus colubris) to 16.6 gin the Blue-headed of a panicle, which I also released unharmed. Neith­ Vireo (Vireo solitarius; Dunning 1992). Records of er of the birds would have attracted my attention bird entanglement in plants other than common had they not been struggling and v.rithin 2 m of the burdock are rare (e.g., Tucker 1955, Hampson 1970, footpath. They could not have struggled long Skutch 1973, McNicholl 1988, Craves 1998). The before succumbing to exhaustion or predation. largest bird entangled in plants appears to be a 32.1 This report adds to the scant literature on bird g Swainson's Thrush (Catharus ustalatus) en­ entanglement in plants other than common bur­ tangled in the seed pod of encha11ter's Nightshade dock. Both birds fit into the size range typical of (Circaea quadrisulcata; Craves I 998). In this note birds entangled in plants, with mean weights of 6.3 1 record two instances in which birds were trapped g for the Green Hermit and 10.2 g for the Banana­ in panicles of the grass Pharus latifolius (family quit (ffrench, 1991 ). The sighting of two indepen­ Poaceae). dently trapped birds, despite a low probability of P. latij'olius is widely distributed in tropical detection, coupled with the abundance of the North, Central and South America and the Carib­ grass, suggest that panicles of P. latifolius may bean (e.g., Howard 1979, G6rts-van Rijn 1990). pose an underestimated hazard to small birds. The Specimens of P. latifolius at the National Herbar­ Green Hermit appears to be particularly vulnerable ium of Trinidad and Tobago show the species to be as it often hovers in the understorey with its widespread in forested areas of both islands. pendulous tail inviting entanglement. Bananaquits Specimens with fruiting bodies were collected in all inhabit all levels of vegetation and have even been months except January, June and October. The seen turning over leaves 011 a forest path (Snow flower is an open panicle that is brittle, with primary a11d Snow 1971 ). Throughout the wide range of P. branches tl1at easily break away from the main latifolius, many more species of birds may en­ rachis (Howard 1979, G6rts-van Rijn 1990). The fe­ counter it with potentially fatal results. male flowers bear hooked hairs, becoming adhesive Acknowledgements.-! thank Y Baksh-Comeau in fruit; the hooks are tiny, producing a Velcro' and D. B. McNair for reviewing the manuscript and effect ( Howard 1979, G611s-van Rijn 1990). The supplying pertinent references; F. E. Hayes and W. plant presumably relies on passing animals for the Johnson also supplied references. Short Communications 209

LITERATURE CITED Guianas. Koeltz Scientific Books, Koenigstein, Germany. 727 pp. COMEAU, P ., L. GUY, E. HEESTERMAN, AND C. HULL. HOWARD, R. A. 1979. Flora of the Lesser Antilles. 1992. The Trinidad & Tobago Field Natural­ Arnold Arboretum, Harvard University, ists' Club trail guide. Trinidad and Tobago Jamaica Plain, MA . 586 pp . Field Naturalists' Club, Port of Spain, Trinidad. LINCOLN, F. C. 1931 . Some causes of mortality 276 pp. among birds. Auk 48:538-546. CRAVES, J. A. 1998. Swainson's Thrush caught in SKUTCH, A. F. 1973. The life of the hummingbird. enchanter's nightshade. Wilson Bull. 110:569- Crown Publishers, Inc., New York, NY. 95 pp. 570. McNICHOLL, M. K. 1988. Bats and birds stuck on DUNNING, J. B., JR. (ed.). 1992. CRC handbook of burdock .. Prairie Nat. 20:157-160. avian body masses. CRC Press, Boca Raton, SNOW, B. K., ACID D. W. SNow. 1971 . T11e feeding FL. 371pp. ecology of tanagers and honeycreepers in FFRENCH, R. 1991 . A guide to the Birds of Trinidad T1inidad. Auk 88 :291-322. and Tobago. Cornell University Press, Ithaca, TUCKER, H. M. 1955 . Calliope Hummingbird en­ NY. 426 pp. tangled in grass barbs. Condor 57 : 119. G6RTS-VAN RIJN, A. R. A. 1990. Flora of the