DOCSLIB.ORG

Maguari Stork Nesting: Juvenile Growth and Behavior

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Maguari Stork Nesting: Juvenile Growth and Behavior MAGUARI STORK NESTING: JUVENILE GROWTH AND BEHAVIOR BETSY TRENT THOMAS Apartado80844, Caracas1080-A, Venezuela ABSTRACT.--Althoughit has a wide range in tropical South America, the Maguari Stork (Ciconiamaguari) is poorly known. In an 11-yr study of its breedingbiology in the llanos of Venezuela I found the mean clutch size for 3 yr to be 3.2 eggs.The young hatchedasynchro- nously at 29-32 days and usually made their first flight at 60-72 days. Data on egg sizes, weights,and a probabledump egg are given. The weight and growth of two siblings,plum- age succession,and nestling and fledgling behaviorsare described.The fledging successof eggsfrom 55 nests,over 9 yr, was61%. Loss of eggs(presumably from snakepredation) was higher than nestling loss.Although the asynchronouslyhatched young in a clutch varied greatly in weight and continuedthis differencethroughout nestling life, no caseof brood reduction was found in 123 nests during the study. Nestlings were fed mainly frogs and tadpoles,fish, eels, and aquaticrats; food classesand food sizesbrought by adults varied with the age of their young. Maguari Stork nestlingsdo not graspwith their hallux and so are confined to their nestsuntil they can fly. I suggestthat the two black plumagesof nestlings,between the white hatchingdown and the white firstbasic plumage, are for crypsis of the nest-boundyoung. Received29 August1983, accepted I March 1984. THE Maguari Stork ( Ciconiamaguari = Euxen- day of hatching to the postfledgingperiod. uragaleata) is found only in South America and Perhapsbecause of abundantfood on the study is lesswidespread than the other two storksof site, no incident of brood reduction was ob- the Western Hemisphere, the Wood Stork served in 123 nests. The manner and size of (Mycteria americana)and the Jabiru (Jabirumyc- food presentedto the young and sibling growth teria), both of which range farther to the north data, however, suggest that brood reduction (Blake 1977). Although the three speciesare may not occurin this speciesor may be rare. largely sympatric in South America, the wide Lossof eggs,presumably to snakes,was higher ranges indicated on distributional maps are than nestling lossesfrom all causescombined. somewhat misleading, becausethese storksare One puzzling aspect of Maguari chick de- ecologicallyrestricted to tropical, low-eleva- velopment is the successionof two different tion wetlands and adjacentnonforested areas. black plumages,between the white hatching In Venezuela the three storksare found togeth- down and the white first basicplumage (Hum- er in the interior of the country, a vast savanna phrey and Parkes 1959) acquired at fledging. I called the llanos. suggestthat the black plumagesare for crypsis Mayr and Amadon (1951) and Kahl (1971a) becauseof their timing and the fact that Ma- have suggestedthat this stork is closelyrelated guari Stork nestlings,like adults,do not grasp to the White Stork (Ciconiaciconia), and this pa- with their hallux and thus cannot leave their per gives a broader basisfor a comparisonof nests to escapepredators. the young with thoseof the better known White Stork (Schtiz 1942, 1943, 1944; Haverschmidt STUDY SITE AND METHODS 1949). The principal published information about the Maguari Stork is from 2 months of The studysite (08ø31'N,67ø35'W) was a cattle ranch observationsof nestingbirds in Argentina (Kahl locatedroughly in the center of the Venezuelan lla- nos, about 45 km south of Calabozo in the state of 1971b).For 11 yr I followed the seasonalbreed- Guarico. Troth (1979) provided an account of the ing of all Maguari Storks on a ranch in the vegetation of this ranch and Thomas (1979a) an an- llanos of Venezuela.I give data on the eggsand notatedlist of its bird species.The llanos are grass- on the asynchronouslyhatched young from the land savannawith scatteredpalms and clumps of other trees. During the rainy season(generally May • Present address:I Wetsel Road, Troy, New York to November)Maguari Storks nest, usually from June 12182 USA. to October (Thomasin press),when much of the sa- 812 The Auk 101: 812-823. October 1984 October1984] MaguariStork Nesting 813 TABLE1. Maguari Stork hatching and fledging success. Eggs Young Total Number Percentage Percentage success Year of nests Laid Hatched hatched Fledged fledged (%) 1973 2 5 5 100.0 4 80.0 80.0 1974 16 43 24 55.8 18 75.0 41.8 1975 15 a 47 24 51.0 19 79.1 40.4 1976 10 36 28 77.7 24 85.7 66.7 1977 2 7 4 57.1 4 100.0 57.1 1978 5 14 9 64.2 5 55.5 35.7 1979 1 4 3 75.0 3 100.0 75.0 1980 1 4 3 75.0 3 100.0 75.0 1981 3 11 10 90.9 9 90.0 81.8 Total 55 171 110 71.8 89 85.0 61.5 ' In 1975 all the young were taken from five nestsby poachers.Four of these nestsare included here, becausetheir nine young storkswere nearly old enough to fledge. vanna is flooded to a depth of 5-100 cm. Maguari Eggs.--MaguariStorks laid eggsfrom May to Storkson the study site usedan area of approximate- November;in any one year, however, the nest- ly 690 ha. I studiedthe birds from 1972through 1982, ing seasonlasts no more than about 4 months. and from 1973 to 1976 I banded all nestlings (n = The timing difference is causedby the varia- 128). The detailsof handling techniquesare reported tion in the beginning of the nestingperiod and elsewhere (Thomas 1977). Some observationsof nest- ling behavior were made during banding; other data amount of rainfall (Thomasin press).The only were from dawn-to-dusk observations from blinds pair that laid eggs in late May did not relay and from field censusesduring all nesting stages. after their young fledged in late August.Nest- I used8 x 32 binoculars,a 15-60x telescope,spring ing in October was by late-returning birds, balancePesola scales of 100, 300, 1,000, and 2,500 g, usually young inexperiencedindividuals. The a grocer's scale that registered to 10 kg, a vernier eggs were small in relation to the size of the scalecalibrated to 0.1 mm, and a stop watch. I took adult female(œ egg is ca.3.3% of femaleweight), notesby hand or by using a portable tape recorder. and the clutch size was usually 3-4 eggs.The Color notes were made by comparisonwith color mean was 2.8 eggs (n = 20 clutches) in 1974, swatchesin hand (Smithe 1975). Only nestswhere 3.4 (n = 17) in 1975, and 3.6 (n = 12) in 1976, the number of eggs laid and number hatched were known are listed in Table 1. Standard deviations and for an overall mean of 3.2 eggsper clutch.Late rangesare given for egg sizesand weights.The length rains and low precipitation during May-June of food items was either measured from collected in 1974 may have been associatedwith the samplesor estimated to the nearest centimeter, and smaller clutches. the weight was calculatedfrom preservedsamples of Eggs are oval to subelliptical (Palmer 1962). food species. They are nearly smoothand dull white but may become stained during incubation. The mean RESULTS length of 54 eggs from 5 yr was 75.19 mm (+ 3.29, range=69.1-85.0) and their mean Nests.--Bothmembers of Maguari Storkpairs width was 52.56 mm (+ 2.66, range = 46.0- sharein all phasesof nestbuilding, incubation, 57.0). Mean weight of 42 fresh eggs,within a brooding, and feeding the young. In Venezue- week of laying and only slightly incubated,was la their nests were built on bushes and in small 116.4g (+ 9.42,range = 100-140).One freshegg trees 1.4-6.3 m high (ThomasMS) but not on was separated into its component parts and the ground, as Kahl (1971b) found in Argen- weighed:the shell was 14 g (11%),the yolk 25 tina. Nests were platforms of sticksabout ! m g (21%), and the albumen 83 g (68%). The yolk in diametercovered with grasssloping slightly was Flame Scarlet(Smithe 1975), perhaps be- down toward the center. Most nests were in cause of the carotenoids, which are the com- small colonies (77%), but some (23%) were sol- ponentsof somefish and crustacea(Roudybush itary. Details of nestsand nest-buildingwill be et al. 1979);White Stork eggsare alsored-yolked reported elsewhere. (Goldsmith 1965). 814 BETSYTI•ENT THOMAS [Auk,Vol. 101 At three closelywatched nests, the storkslaid white down on the capital,spinal, humerat, alar, their eggs on alternate days, and full-time in- and ventral tracts. By day 4, emerging black cubation began with the secondor third egg. semiplumes(Lucas and Stettenheim 1972: Fig. Thus, in a clutch of four, there was sometimes 45) cover the frontal, coronal,and occipitalareas a differenceof a week in the age of the asyn- to the dorsalcervical line. Subsequently,black chronouslyhatched young. semiplumesalso cover the auricular, malar, and I found one presumed instance of a dump submalar areas, as well as the ventral, lateral, egg. In a nestwith three eggswhere incubation and dorsal cervical areas. At 1 week, a second had progressedfor about 21 days,a fourth egg generationof down, which is BlackishNeutral appeared.Three days later a broken stork egg Gray, starts to appear on the body. The first shell was underneath the nest. No eggs were white down is protoptile and the secondblack missing from nearby nests,and the three eggs down mesoptile (Van Tyne and Berger 1971). of this nest hatched 2-5 days apart. Therefore, The seconddowny featherspush out the first the shell below the nest was probably that of white downy feathers, many of which remain the dump egg. This nest might have been par- attached to the tips, and the effect is that of ticularly vulnerable to dumping, becauseit was regularly spacedwhite stars (Thomas 1979b).
Load more

Recommended publications
  • Handling and Intake of Plastic Debris by Wood Storks at an Urban Site in South-Eastern Brazil: Possible Causes and Consequences
    NORTH-WESTERN JOURNAL OF ZOOLOGY 11 (2): 372-374 ©NwjZ, Oradea, Romania, 2015 Article No.: 147601 http://biozoojournals.ro/nwjz/index.html Handling and intake of plastic debris by Wood Storks at an urban site in South-eastern Brazil: possible causes and consequences Ivan SAZIMA1,* and Giulia B. D’ANGELO2 1. Museu de Zoologia, Universidade Estadual de Campinas, 13083-970 Campinas, São Paulo, Brazil. 2. Instituto de Biologia, Universidade Estadual de Campinas, 13083-970 Campinas, São Paulo, Brazil. *Corresponding author, I. Sazima, E-mail: [email protected] Received: 20. September 2014 / Accepted: 12. December 2014 / Available online: 01. November 2015 / Printed: December 2015 Anthropogenic inedible debris increases in the picked pieces of plastic cable were individually identified food chain of seabirds, marine turtles, and by differences on neck feathering and bill colour. cetaceans and becomes a worldwide problem (e.g. Sequenced photographs allowed the timing of the behavioural events for two of these individuals. Denuncio et al. 2011, Avery-Gomm et al. 2013, Throughout the observations, we used the “ad libitum” Schluyter et al. 2013, Donnelly-Greenan et al. 2014, sampling (Altmann 1974), which is adequate to record Provencher et al. 2015), but this material is rarely rare events. reported entering the food chain of inland wildlife (Peris 2003, Booth 2011, Henry et al. 2011). Storks Among small groups of Wood Storks that varied of the genus Ciconia are opportunistic visual from 2 to 8 migrant individuals comprised of up to hunters that prey mostly on fish, frogs, snakes, 2 adults and 6 juveniles, we recorded the small mammals, and a variety of insects (Elliott behaviour of 4 juveniles (subadults sensu Coulton 1992).
    [Show full text]
  • Hungary & Transylvania
    Although we had many exciting birds, the ‘Bird of the trip’ was Wallcreeper in 2015. (János Oláh) HUNGARY & TRANSYLVANIA 14 – 23 MAY 2015 LEADER: JÁNOS OLÁH Central and Eastern Europe has a great variety of bird species including lots of special ones but at the same time also offers a fantastic variety of different habitats and scenery as well as the long and exciting history of the area. Birdquest has operated tours to Hungary since 1991, being one of the few pioneers to enter the eastern block. The tour itinerary has been changed a few times but nowadays the combination of Hungary and Transylvania seems to be a settled and well established one and offers an amazing list of European birds. This tour is a very good introduction to birders visiting Europe for the first time but also offers some difficult-to-see birds for those who birded the continent before. We had several tour highlights on this recent tour but certainly the displaying Great Bustards, a majestic pair of Eastern Imperial Eagle, the mighty Saker, the handsome Red-footed Falcon, a hunting Peregrine, the shy Capercaillie, the elusive Little Crake and Corncrake, the enigmatic Ural Owl, the declining White-backed Woodpecker, the skulking River and Barred Warblers, a rare Sombre Tit, which was a write-in, the fluty Red-breasted and Collared Flycatchers and the stunning Wallcreeper will be long remembered. We recorded a total of 214 species on this short tour, which is a respectable tally for Europe. Amongst these we had 18 species of raptors, 6 species of owls, 9 species of woodpeckers and 15 species of warblers seen! Our mammal highlight was undoubtedly the superb views of Carpathian Brown Bears of which we saw ten on a single afternoon! 1 BirdQuest Tour Report: Hungary & Transylvania 2015 www.birdquest-tours.com We also had a nice overview of the different habitats of a Carpathian transect from the Great Hungarian Plain through the deciduous woodlands of the Carpathian foothills to the higher conifer-covered mountains.
    [Show full text]
  • First Record of an Extinct Marabou Stork in the Neogene of South America
    First record of an extinct marabou stork in the Neogene of South America JORGE IGNACIO NORIEGA and GERARDO CLADERA Noriega, J.I. and Cladera, G. 2008. First record of an extinct marabou stork in the Neogene of South America. Acta Palaeontologica Polonica 53 (4): 593–600. We describe a new large species of marabou stork, Leptoptilus patagonicus (Ciconiiformes, Ciconiidae, Leptoptilini), from the late Miocene Puerto Madryn Formation, Chubut Province, Argentina. The specimen consists mainly of wing and leg bones, pelvis, sternum, cervical vertebrae, and a few fragments of the skull. We provisionally adopt the traditional system− atic scheme of ciconiid tribes. The specimen is referred to the Leptoptilini on the basis of similarities in morphology and intramembral proportions with the extant genera Ephippiorhynchus, Jabiru,andLeptoptilos. The fossil specimen resembles in overall morphology and size the species of Leptoptilos, but also exhibits several exclusive characters of the sternum, hu− merus, carpometacarpus, tibiotarsus, and pelvis. Additionally, its wing proportions differ from those of any living taxon, providing support to erect a new species. This is the first record of the tribe Leptoptilini in the Tertiary of South America. Key words: Ciconiidae, Leptoptilos, Miocene, Argentina, South America. Jorge I. Noriega [[email protected]], Laboratorio de Paleontología de Vertebrados, CICYTTP−CONICET, Matteri y España, 3105 Diamante, Argentina; Gerardo Cladera [[email protected]], Museo Paleontológico Egidio Feruglio, Avenida Fontana 140, 9100 Trelew, Argentina. Introduction Institutional abbreviations.—BMNH, Natural History Mu− seum, London, UK; CICYTTP, Centro de Investigaciones The stork family (Ciconiidae) is a well−defined group of Científicas y Transferencia de Tecnología a la Producción, waterbirds, traditionally divided into three tribes: the Myc− Diamante, Argentina; CNAR−KB3, collections of locality 3 of teriini, the Ciconiini, and the Leptoptilini (Kahl 1971, 1972, the Kossom Bougoudi area, Centre National d’Appui à la 1979).
    [Show full text]
  • Detailed Species Accounts from The
    Threatened Birds of Asia: The BirdLife International Red Data Book Editors N. J. COLLAR (Editor-in-chief), A. V. ANDREEV, S. CHAN, M. J. CROSBY, S. SUBRAMANYA and J. A. TOBIAS Maps by RUDYANTO and M. J. CROSBY Principal compilers and data contributors ■ BANGLADESH P. Thompson ■ BHUTAN R. Pradhan; C. Inskipp, T. Inskipp ■ CAMBODIA Sun Hean; C. M. Poole ■ CHINA ■ MAINLAND CHINA Zheng Guangmei; Ding Changqing, Gao Wei, Gao Yuren, Li Fulai, Liu Naifa, Ma Zhijun, the late Tan Yaokuang, Wang Qishan, Xu Weishu, Yang Lan, Yu Zhiwei, Zhang Zhengwang. ■ HONG KONG Hong Kong Bird Watching Society (BirdLife Affiliate); H. F. Cheung; F. N. Y. Lock, C. K. W. Ma, Y. T. Yu. ■ TAIWAN Wild Bird Federation of Taiwan (BirdLife Partner); L. Liu Severinghaus; Chang Chin-lung, Chiang Ming-liang, Fang Woei-horng, Ho Yi-hsian, Hwang Kwang-yin, Lin Wei-yuan, Lin Wen-horn, Lo Hung-ren, Sha Chian-chung, Yau Cheng-teh. ■ INDIA Bombay Natural History Society (BirdLife Partner Designate) and Sálim Ali Centre for Ornithology and Natural History; L. Vijayan and V. S. Vijayan; S. Balachandran, R. Bhargava, P. C. Bhattacharjee, S. Bhupathy, A. Chaudhury, P. Gole, S. A. Hussain, R. Kaul, U. Lachungpa, R. Naroji, S. Pandey, A. Pittie, V. Prakash, A. Rahmani, P. Saikia, R. Sankaran, P. Singh, R. Sugathan, Zafar-ul Islam ■ INDONESIA BirdLife International Indonesia Country Programme; Ria Saryanthi; D. Agista, S. van Balen, Y. Cahyadin, R. F. A. Grimmett, F. R. Lambert, M. Poulsen, Rudyanto, I. Setiawan, C. Trainor ■ JAPAN Wild Bird Society of Japan (BirdLife Partner); Y. Fujimaki; Y. Kanai, H.
    [Show full text]
  • Spring Migration of Soaring Birds Over the Bosphorus, Turkey, in 2006
    Spring migration of soaring birds over the Bosphorus, Turkey, in 2006 ÖzkAN ÜNER, kEREM ALi BoyLA, ERGÜN BAcAk, ERTuğRuL BiREL, İLhAN ÇELikoBA, CEM DALYAN, EVRIM TABUR & ÜMIT YARDIM The Bosphorus is one of the most important migration bottlenecks in the Middle East. However, most counts have been done during autumn and complete spring counts are very few. In spring 2006, a complete count of migrating soaring birds over the Bosphorus was carried out. We report a total of 100 051 birds, which consisted of 51 958 White Storks Ciconia ciconia, 16 185 Common Buzzards Buteo buteo, 15 232 Lesser Spotted Eagles Aquila pomarina and 9085 Honey Buzzards Pernis apivorus. The study demonstrates the importance of the Bosphorus for the spring migration of soaring birds. INTRODUCTION Turkey has major Western Palearctic migration crossroads, with corridors and bottlenecks for soaring birds in the northwestern (Bosphorus in Istanbul, Figure 1), northeastern (Borçka, Artvin province) and southern (Belen, Hatay province) parts of the country (Grimmett & Jones 1989). The Bosphorus is a well-known migration bottleneck for soaring birds due to its location at the junction between Europe and Asia. The whole population of eastern White Storks Ciconia ciconia, over 340 000 birds, flies over the Bosphorus. Zalles & Bildstein (2000) reported between 29 000 and 75 000 migrant raptors in autumn over the Bosphorus whereas a very recent multi-station but short survey has shown that more than 150 000 raptors use the area in autumn (Milvus Group 2008). Most of the world population of Lesser Spotted Eagles Aquila pomarina and Levant Sparrowhawks Accipiter brevipes, at least in autumn, crosses into Asia via the Bosphorus (Kirwan et al 2008) using the east Mediterranean route (Shirihai et al 2000).
    [Show full text]
  • Jabiru Mycteria (Jabiru Stork)
    UWI The Online Guide to the Animals of Trinidad and Tobago Ecology Jabiru mycteria (Jabiru Stork) Family: Ciconiidae (Storks) Order: Ciconiiformes (Storks, Herons and Ibises) Class: Aves (Birds) Fig. 1. Jabiru stork, Jabiru mycteria. [https://en.wikipedia.org/wiki/Jabiru#/media/File:Jabiru_(Jabiru_mycteria)_2.JPG, downloaded 1 March 2017] TRAITS. Jabiru mycteria is one of the largest flying birds on earth, being the largest in the Americas and one of the three stork species found there. Adult jabiru storks can reach 1.2m tall with a wing span of 2.6m. Their bill is large and black, somewhat upturned, with lengths of up to 30cm (Fig. 1). Males are larger than females, and both sexes can be identified by the band of red skin at the base of the neck. Adult storks possess all-white plumage on the body. The head and neck lacks feathers except for a cluster of grey feathers on the back of the head. The juveniles have white feathers with greyish-brown edges (McKinley, 2006; Borjas, 2004). DISTRIBUTION. Jabiru mycteria is native to South American countries such as Argentina, Brazil, Belize, Colombia, Guyana, Honduras, Nicaragua and Venezuela (Fig. 2). Jabirus can have also been sighted in Mexico, Panama, Trinidad and Tobago, Grenada, United States and Uruguay (IUCN, 2016). UWI The Online Guide to the Animals of Trinidad and Tobago Ecology HABITAT AND ACTIVITY. Jabiru storks are diurnal birds and often feed singly or in pairs but can also be found feeding in large groups (Kahl, 1973). They can be found around coastal lagoons, savannas, marshes and also ponds (Belize Zoo, 2017; Pantanal, 2006).
    [Show full text]
  • Wood-Stork-2005.Pdf
    WOOD STORK Mycteria americana Photo of adult wood stork in landing posture and chicks in Close-up photo of adult wood stork. nest. Photo courtesy of USFWS/Photo by George Gentry Photo courtesy of U.S. Army Corps of Engineers. FAMILY: Ciconiidae STATUS: Endangered - U.S. Breeding Population (Federal Register, February 28, 1984) [Service Proposed for status upgrade to Threatened, December 26, 2013] DESCRIPTION: Wood storks are large, long-legged wading birds, about 45 inches tall, with a wingspan of 60 to 65 inches. The plumage is white except for black primaries and secondaries and a short black tail. The head and neck are largely unfeathered and dark gray in color. The bill is black, thick at the base, and slightly decurved. Immature birds have dingy gray feathers on their head and a yellowish bill. FEEDING HABITS: Small fish from 1 to 6 inches long, especially topminnows and sunfish, provide this bird's primary diet. Wood storks capture their prey by a specialized technique known as grope-feeding or tacto-location. Feeding often occurs in water 6 to 10 inches deep, where a stork probes with the bill partly open. When a fish touches the bill it quickly snaps shut. The average response time of this reflex is 25 milliseconds, making it one of the fastest reflexes known in vertebrates. Wood storks use thermals to soar as far as 80 miles from nesting to feeding areas. Since thermals do not form in early morning, wood storks may arrive at feeding areas later than other wading bird species such as herons.
    [Show full text]
  • Spread-Wing Postures and Their Possible Functions in the Ciconiidae
    THE AUK A QUARTERLY JOURNAL OF ORNITHOLOGY Von. 88 Oc:roBE'a 1971 No. 4 SPREAD-WING POSTURES AND THEIR POSSIBLE FUNCTIONS IN THE CICONIIDAE M. P. KAI-IL IN two recent papers Clark (19'69) and Curry-Lindahl (1970) have reported spread-wingpostures in storks and other birds and discussed someof the functionsthat they may serve. During recent field studies (1959-69) of all 17 speciesof storks, I have had opportunitiesto observespread-wing postures. in a number of speciesand under different environmentalconditions (Table i). The contextsin which thesepostures occur shed somelight on their possible functions. TYPES OF SPREAD-WING POSTURES Varying degreesof wing spreadingare shownby at least 13 species of storksunder different conditions.In somestorks (e.g. Ciconia nigra, Euxenuragaleata, Ephippiorhynchus senegalensis, and ]abiru mycteria) I observedno spread-wingpostures and have foundno referenceto them in the literature. In the White Stork (Ciconia ciconia) I observedonly a wing-droopingposture--with the wings held a short distanceaway from the sidesand the primaries fanned downward--in migrant birds wetted by a heavy rain at NgorongoroCrater, Tanzania. Other species often openedthe wingsonly part way, in a delta-wingposture (Frontis- piece), in which the forearmsare openedbut the primariesremain folded so that their tips crossin front o.f or below the. tail. In some species (e.g. Ibis leucocephalus)this was the most commonly observedspread- wing posture. All those specieslisted in Table i, with the exception of C. ciconia,at times adopted a full-spreadposture (Figures i, 2, 3), similar to those referred to by Clark (1969) and Curry-Lindahl (1970) in severalgroups of water birds.
    [Show full text]
  • Checklist of Suffolk Birds
    Suffolk Bird Checklist status up to and including 2001 records (2002 & 2003 where stated) - not including BOURC category E R = records considered by BBRC r = records considered by SORC, requiring full descriptions see end of list for Category D and abundance codes red-throated diver common winter visitor and passage migrant, rare inland black-throated diver uncommon winter visitor and passage migrant, rare inland great northern diver uncommon winter visitor and passage migrant yellow (white)-billed diver R accidental, 3 records; 1852, 1978 and 1994 little grebe locally common resident, passage migrant and winter visitor great crested grebe locally common resident, passage migrant and winter visitor red-necked grebe uncommon winter visitor and passage migrant, mostly coastal slavonian grebe uncommon winter visitor and passage migrant, mostly coastal black-necked grebe uncommon winter visitor and passage migrant northern fulmar fairly common summer visitor and passage migrant Cory's shearwater r very rare (autumn) passage migrant; 28 records of 37 individuals, all post 1973 great shearwater r accidental, 6 records; 3 post 1950 sooty shearwater uncommon autumn migrant Manx shearwater uncommon passage migrant, mainly autumn Balearic shearwater r very rare passage migrant, 9 records, all since 1998 Leach's storm petrel r scarce passage migrant European storm petrel r very rare passage migrant, 28 individuals since 1950 northern gannet common offshore passage migrant great cormorant locally common passage migrant and winter visitor, a few oversummer
    [Show full text]
  • Neotropical News Neotropical News
    COTINGA 1 Neotropical News Neotropical News Brazilian Merganser in Argentina: If the survey’s results reflect the true going, going … status of Mergus octosetaceus in Argentina then there is grave cause for concern — local An expedition (Pato Serrucho ’93) aimed extinction, as in neighbouring Paraguay, at discovering the current status of the seems inevitable. Brazilian Merganser Mergus octosetaceus in Misiones Province, northern Argentina, During the expedition a number of sub­ has just returned to the U.K. Mergus tropical forest sites were surveyed for birds octosetaceus is one of the world’s rarest — other threatened species recorded during species of wildfowl, with a population now this period included: Black-fronted Piping- estimated to be less than 250 individuals guan Pipile jacutinga, Vinaceous Amazon occurring in just three populations, one in Amazona vinacea, Helmeted Woodpecker northern Argentina, the other two in south- Dryocopus galeatus, White-bearded central Brazil. Antshrike Biata s nigropectus, and São Paulo Tyrannulet Phylloscartes paulistus. Three conservation biologists from the U.K. and three South American counter­ PHIL BENSTEAD parts surveyed c.450 km of white-water riv­ Beaver House, Norwich Road, Reepham, ers and streams using an inflatable boat. Norwich, NR10 4JN, U.K. Despite exhaustive searching only one bird was located in an area peripheral to the species’s historical stronghold. Former core Black-breasted Puffleg found: extant areas (and incidently those with the most but seriously threatened. protection) for this species appear to have been adversely affected by the the Urugua- The Black-breasted Puffleg Eriocnemis í dam, which in 1989 flooded c.80 km of the nigrivestis has been recorded from just two Río Urugua-í.
    [Show full text]
  • The History of the Southern Florida Wood Stork Population
    Wilson Bull., 98(3), 1986, pp. 368-386 THE HISTORY OF THE SOUTHERN FLORIDA WOOD STORK POPULATION JAMES A. KUSHLAN AND PAULA C. FROHRING ’ AswnAcr.-The largest segment of the North American Wood Stork (Mycteria ameri- cam) population traditionally nested in southern Florida, where its perceived population decrease over the last 50 years resulted in its addition to the Federal endangered species list. Previously published reports placed the southern Florida population at 30,000 to 100,000 storks. A complete search of published and unpublished records of Wood Storks nesting in southern Florida, however, failed to support such a long-term population decrease. We cannot demonstrate that the historical population was any larger than it was in 1967, when there were 9400 pairs. The Corkscrew-Big Cypress nesting group, not that of the Everglades, was historically the most numerically important population segment. The historic nesting location for southernmost Wood Storks was not inland in the Everglades but on Cape Sable, which has been subject to the effects of drainage canals. The population size of several decades ago is irrelevant to current conservation strategy because the southern Florida marshes have been irrevocably altered reducing their ability to support storks. We can document a population decrease of 75% from 1967 to 1981-82 in southern Florida, a time frame coincident with the operation of water management policies in the Everglades. Wood Storks recently have begun abandoning traditional colony sites in Everglades National Park in favor of sites in shallow reservoirs to the north. Drainage of the Big Cypress Swamp and maintenance of seasonally excessive water levels in the Everglades of Everglades National Park account for the storks’ repeated nesting failure and population decrease.
    [Show full text]
  • Factors Affecting Reproductive Success of Wood Storks (Mycteria Americana) in East-Central Georgia
    The Auk 112(1):237-243, 1995 FACTORS AFFECTING REPRODUCTIVE SUCCESS OF WOOD STORKS (MYCTERIA AMERICANA) IN EAST-CENTRAL GEORGIA MALCOLM C. COULTER• AND A. LAWRENCEBRYAN, JR. SavannahRiver Ecology Laboratory, Drawer E, Aiken,South Carolina 29802, USA ABS?R•cr.--From1984 through 1989, we examinedthe reproductivesuccess of WoodStorks (Mycteriaamericana) at the Birdsvillecolony in east-centralGeorgia. Average fledging success rangedamong years from 0.33to 2.16fledglings per nest.For neststhat producedfledglings, prey availabilitywas an importantfactor affecting reproductive success. Yearly averageprey densitiesat foragingsites were significantlycorrelated with the averagenumber of fledglings producedfrom successfulnests. Among 243 nestsobserved, all eggsor chickswere lostfrom 104(43%) nests. Five factorswere associatedwith the lossof entire clutchesor broods.During the two driest years, 1985 and 1988, raccoon(Procyon lotor) predation eliminated almost all chicks.Many nestswere abandonedearly in 1989, following periodsof cold weather when the parentsappeared to be under stress.In 1985, the birds desertedthe colony before egg laying when the area experiencedfreezing weather. Following nest abandonmentswithin the colony,paired adultsthat presumablyhad abandonedtheir nestswere involved in nest takeoversthat alsocaused the lossof eggsand chicks.Three stormsduring the studycaused the lossof a few nests.Some losses were due to unknown factors.The importanceof these mortality factorsvaried from year to year. Nest abandonmentsand subsequentaggression seemto be related to cold periodsearly in the season.Raccoon predation seems to be related to drying out of the water under the colony.This suggeststhat the storkshave a window in time when it is bestto breed--afterthe winter and earlyspring cold weather and beforethe water dries under the colony in the summer.Received 4 December1991, accepted 15 November 1992.
    [Show full text]