Proceedings of the Fourth International Partners in Flight Conference: Tundra to Tropics 62–70

DYNAMICS OF PASSERINE MIGRATION IN VERACRUZ, MÉXICO

EDUARDO MARTÍNEZ LEYVA,1,4 ERNESTO RUELAS INZUNZA,2 OCTAVIO CRUZ CARRETERO,3 JAMES L. BARR,1 ELISA PERESBARBOSA ROJAS,1 IRVING CHÁVEZ DOMÍNGUEZ,1 GUSTAVO RAMÓN LARA,1 RAFAEL RODRÍGUEZ MESA,1 ALEXALDO GARCÍA MIRANDA,1 AND NORMA FERRIZ DOMÍNGUEZ1

1Pronatura Veracruz, Apartado Postal 399, Xalapa, Veracruz, México 91000; 2Cornell Lab of Ornithology, 159 Sapsucker Woods Road, Ithaca, New York 14850, USA; and 3Envirological Services, Inc., 22 Geer Road, Sandia Park, New Mexico 87047, USA

Abstract. The state of Veracruz, along the gulf coast of México, is an important fl yway for Neotropical migrants. Many passerines and other land birds use remnants of native vegetation as stopover sites for shelter and refueling during their migration. We operate a long-term banding station in a coastal forest near the fi shing village of Playa Salinas, in the municipality of Alvarado, with the purpose of studying patterns of spring migration. After nine seasons of mist-netting and banding, we recorded 77 species of birds using this site as regular northward transients and have banded nearly 1000 individuals per season. The majority of the records (41.9% of the total), are from six species: Least Flycatcher (Empidonax minimus), Yellow Warbler (Dendroica petechia), Swainson’s Thrush (Catharus ustulatus), Gray Catbird (Dumetella carolinensis), Yellow-breasted Chat (Icteria virens), and Wilson’s Warbler (Wilsonia pusilla). We provide some notes on the timing of their migration and annual capture rates. Multiple-year recaptures of banded individuals are low (37 individuals of 10 species, from a total of 8479 individuals banded in the period 1999-2007). Recaptures ranging from 2-8 years (mean 2.9 years) show either low site fi delity or low interannual survivorship. Our banding station is one of the longest-running operations in Latin America. Its results provide important data on the ecology of passerine migration and contribute to the conservation of stopover habitats for transient and winter residents.

Keywords: Passerines, spring migration, Veracruz, Mexico, stopover ecology, banding station.

DINÁMICA DE LA MIGRACIÓN DE PASERINAS EN VERACRUZ, MÉXICO Resumen. El estado de Veracruz, a lo largo de la costa del Golfo de México, es una importante ruta para migratorias neotropicales. Muchas paserinas y otras aves terrestres usan los remanentes de vegetación como sitios de descanso, alimentación y protección durante su migración. Operamos una estación de anillado de largo plazo en un bosque costero cerca de la communidad de Playa Salinas, en el municipio de Alvarado, con el propósito de estudiar patrones de migración. Después de nueve temporadas de captura y anillado, hemos registrado 77 especies de aves usando este sitio regularmente en su camino al norte y hemos anillado cerca de 1000 individuos por temporada. La mayoría de los registros (41.9 % del total) pertenecen a 6 especies: Empidonax minimus, Dendroica petechia, Catharus ustulatus, Dumetella carolinensis, Icteria virens, y Wilsonia pusilla. Aquí aportamos algunas notas sobre la temporalidad de su migración y tasas anuales de captura. Las recapturas de individuos en múltiples años son pocas (37 individuos de 10 especies, de un total 8479 individuos anillados en el periodo 1999-2007). Las recapturas varían de 2 a 8 años (media 2.9 años) y muestran poca fi delidad de sitio o baja sobrevivencia interanual Nuestra estación es una de las más antiguas en operación en Latinoamérica. Los resultados proveen de datos importantes sobre la ecología de la migración de paserinas y contribuye a la conservación de hábitats de reabastecimiento para migratorias de paso y residentes invernales.

INTRODUCTION thirty six of 689 species registered for the state (Martínez-Gómez 1996), are transients or winter Veracruz is well-known as an important fl y- residents that use different habitats along the Gulf way for migratory bird species (Rappole and of Mexico migration route (Warnock and Bishop, Ramos 1994, Ruelas et al. 2005). Two hundred 1998, Barrow et al. 2005, Ruelas et al. 2005).

4 E-mail: [email protected] 63 Proceedings of the Fourth International Partners in Flight Conference

The conservation needs of migrants have dic- the center of the circuit. Nets stay open 07:00- tated the agenda of stopover ecology research 12:00 CST, close during the hours of intense heat, (Lindstrom, 1995, Moore 2000, Mehlman et and open again the late afternoon 17:00-19:30. al. 2005). The rate of loss and the dynamics of PSBS operates annually from mid-April to habitats available for migrants en route make late-May, during the height of spring migra- the basic step of determining the presence tion in Veracruz (about 15 April to 30 May). of species, quantifying the magnitude of the During the fi rst season of banding in 1999, the populations using local stopover habitats, and station operated for a shorter season, only until understanding the role of habitats in migrant early May, because it was at in an experimen- bird ecology (Moore et al. 1993, 2005, Yong et al. tal stage (5 April to 3 May). We placed US Fish 1998, Woodrey et al. 2005) a focus in migration and Wildlife Service aluminum bands on all stopover research. migratory species except for the Ruby-throated Key questions include: 1) How diverse is the Hummingbird (for all scientifi c names of bird assemblage of migratory land birds in the Gulf species, see Table 1), because they require spe- of Mexico spring fl yway? 2) Are there species or cial bands and techniques for their marking. populations of special concern among the birds regularly recorded there? 3) Are these popu- RESULTS lations constant among years or is there high interannual variation? 4) What is the phenology SPECIES PRESENT AND RELATIVE ABUNDANCE IN THE of their migrations? 5) Are these temporal pat- VERACRUZ ASSEMBLAGE terns constant or variable among years? 6) Are there new insights into migrant-bird/local-hab- During the spring fi eld seasons 1999-2007, a itat relationships emerging from our study site? total of 8479 individuals (77 species of 16 fami- In order to answer these questions, Pronatura lies, Table 1), were captured and banded at PSBS. Veracruz has operated a bird banding station The species most commonly captured were Least since the spring of 1999 along the Gulf Coast of Flycatcher (11.3% of captures), Yellow Warbler Veracruz, México. (11.1%), Swainson’s Thrush (6.1%), Gray Catbird In this paper, we describe the general pat- (5.6%), Yellow-breasted Chat (4.1%) and Wilson’s terns of passerine migration recorded from Warbler (3.7%) (Table 1). a banding station in the small coastal village PSBS samples mostly passerines, and the of Playa Salinas, near the city of Alvarado, families with the largest number of species Veracruz. We list the species recorded through represented were Parulidae (39.3% of cap- the operation of mist nets, quantify their cap- tures), Tyrannidae (29.4%) and Vireonidae ture rates, provide some measures of interan- (5.3%). Unidentifi ed Empidonax species belong- nual variation, and report simple survivorship ing to the Traill’s/Alder Flycatcher “complex” estimates from recaptured individuals. We also accounted for 5.4% of all captures. Because spe- highlight other important fi ndings based on cies-level identifi cation was not attempted dur- band recoveries such as records of species new ing the 2002-2005 seasons for any problematic for the region and the state. Empidonax, the percentage of captures for that genus is higher for that period, with the cat- METHODS egory “unidentifi ed fl ycatcher” accounting for 8.9% of all captures during those years. HABITATS AROUND THE BANDING STATION CAPTURE RATES AND OTHER MEASURES FROM MIST- The Playa Salinas Banding Station (PSBS) NET SAMPLES operates within fragmented remnants of tropi- cal deciduous forest and coastal oak savanna Captures per season varied greatly for a con- with a predominance of trees from the genus stant site, from 448-1428 birds per fi eld season Quercus, Coccoloba, and the palm Sabal mexi- (mean of 947 captures). The seasonal mean cap- cana. Understory is dominated by species of the ture rate had over a three-fold interannual vari- Bromeliaceae family, specially the Pinguin bro- ation, from 8.4 to 29.1 birds per day of standard meliad (Bromelia pinguin), and second-growth operation (Table 2). The taxonomic make-up of shrubs. the samples, however, remained relatively con- stant: the number of species sampled annually MIST-NET ARRAY AND SEASONALITY OF OPERATIONS varied from a low of 47 (in 2000) to an atypi- cal maximum of 77 (in 2007) (mean 54 species) PSBS operates 20 mist-nets (2.5 by 12 m, 25 (Table 2); the diversity of families sampled per mm mesh), placed in a permanent circuit of 15 fi eld season did not vary signifi cantly among sites, with a small processing station located at years (10-13 families). Passerine migration in Veracruz—Martínez Leyva et al. 64 44 Total , 1999–2007. 2 2007 ÉXICO , M 15 2006 ERACRUZ , V 12 2005 LVARADO 3 , A 2004 TATION 8 S 2003 Year ANDING 0 B 2002 ALINAS S 2 2001 LAYA P THE 2

2000 AT

1100000002 0010000012 0041010017 0000000303 4 34493150187113243 0000100012 0000000224 0000400004 1316221171649 20020000002 2121887010012380311 0000014139 22142097126445 100100002325 50000001214 10010112410 12 11 12 30 37 152 0 201530010021 106012831334 0001101429 11200223213 14207257331 1142270000134230444 67 77 45 75 235 52 167 156 87 961 1999 MIGRATION

SPRING

DURING

catus fi aviventris fl sp 0 13 18 58 202 88 63 6 8 456 avifrons fl CAPTURED

Accipiter striatus Coccyzus erythrophtalmus Coccyzus americanus Chordeiles acutipennis Archilocus colubris Spyrapicus varius Contopus cooperii Contopus sordidulus Contopus virens Empidonax Empidonax virescens Empidonax alnorum Empidonax traillii Empidonax minimus Empidonax fulvifrons Empidonax Myiarchus crinitus Myiarchus tyrannulus Tyrannus verticalis Tyrannus tyrannus Tyrannus for Vireo gilvus Vireo griseus Vireo bellii Vireo Vireo solitarius MIGRANTS

NEOTROPICAL

OF

FAMILIES

. AND

ONTINUED PECIES ed Flycatcher ed fi Kites, hawks, and eagles (Accipitridae 1) (Accipitridae eagles and hawks, Kites, Sharp-shinned Hawk Cuckoos, roadrunners, and anis (Cuculidae 2) Black-billed Cuckoo Yellow-billed Cuckoo Nighthawks (Caprimulgidae 1) Lesser Nighthawk Hummingbirds (Trochilidae 1) Ruby-throated Hummingbird Woodpeckers (Picidae 1) Yellow-bellied Sapsucker Flycatchers (Tyrannidae 15) Olive-sided Flycatcher Western Wood-pewee Eastern Wood-pewee Yellow-bellied Flycatcher Acadian Flycatcher Alder Flycatcher Willow Flycatcher Least Flycatcher Buff-breasted Flycatcher Unidenti Great-crested Flycatcher Brown-crested Flycatcher Western Kingbird Eastern Kingbird Scissor-tailed Flycatcher TABLE 1. C S Species Warbling Vireo Vireos (Vireonidae 7) White-eyed Vireo Bell’s Vireo Yellow-throated Vireo Blue-headed Vireo 65 Proceedings of the Fourth International Partners in Flight Conference 78 Total 8 2007 7 2006 17 2005 6 2004 13 2003 Year 4 2002 7 2001 11 2000 7191535021052 91029403021216740267 0020010104 16202000011 1010212148341 92782132891290 43000760323 0000042118 0000100001 0230220009 5 221121887344 10104600113 1154513782165 31219547941 0000010102 0020210117 01010811315 0010000001 2452136610755 11200010004 10101241212 0000020002 5 4 11 10 16 14 17 22 100 43 4751595965965544674473 1725 21 107 5 88 32 56 18 39 14 102 104 520 13 24 16 251 8215 93 18 78 30 56 24 93 38 87 26 93 38 202 153 67 937 43 299 1999 capilla fi Vireo philadelphia Vireo olivaceus Hirundo rustica Troglodytes aedon Catharus fuscescens Catharus minimus Catharus ustulatus Hylocichla mustelina Dumetella carolinensis Vermivora pinus Vermivora chrysoptera Vermivora peregrina Vermivora celata Vermivora ru Seiurus aureocapillus Parula americana Dendroica petechia Dendroica pensylvanica Dendroica magnolia Dendroica virens Dendroica townsendi Dendroica fusca Dendroica castanea Dendroica striata Mniotilta varia Setophaga ruticilla Protonotaria citrea Helmitheros vermivorus Limnothlypis swainsonii . ONTINUED Philadelphia Vireo Red-eyed Vireo Swallows (Hirundinidae 1) Barn Swallow Wrens (Troglodytidae 1) House Wren Trushes and allies (Turdidae 4) Veery Hermit Thrush Swainson’s Thrush Wood Thrush Mockingbirds and thrashers (Mimidae 1) Grey Catbird Wood-Warblers (Parulidae 29) Blue-winged Warbler Golden-winged Warbler Tennessee Warbler Orange-crowned Warbler Nashville Warbler TABLE 1. C Species Ovenbird Northern Parula Yellow Warbler Chestnut-sided Warbler Magnolia Warbler Black-throated Green Warbler Townsend’s Warbler Blackburnian Warbler Bay-breasted Warbler Blackpoll Warbler Black-and-white Warbler American Redstart Prothonotary Warbler Worm-eating Warbler Swainson’s Warbler Passerine migration in Veracruz—Martínez Leyva et al. 66 130 Total 1 2007 20 2006 0 2005 16 2004 15 2003 Year 1 2002 69 2001 2 2000 45112671012663 00401611316 32253531011950 11106752326 311111201492 96179 19 11604011412230 21100420010 0000001001 39 80020002206 0000010001 0111110113533 111000111026 651000000001 4781400000005 212 20 16 6 21 43 19 37 18 188 6 1028309165030654841317 1727462655060722142349 33 27 27 29 29 3414 57 15 263 23 25 6 1 13 19 2 89 12 9 97 11 2 10 193 17 3 175 1999 Seiurus noveboracensis Oporornis formosus Oporornis philadelphia Oporornis tolmiei Geothlypis trichas Wilsonia citrina Wilsonia pusilla Wilsonia canadensis Icteria virens Piranga rubra Piranga olivacea Piranga ludoviciana Ammodramus savannarum Melospiza melodia Melospiza lincolnii Pheucticus ludovicianus Passerina caerulea Passerina cyanea Passerina ciris Spiza americana Icterus spurius Icterus galbula . ONTINUED nches, seedeaters, sparrows, and allies fi Northern Waterthrush Kentucky Warbler Mourning Warbler MacGillivray’s Warbler Common Yellowthroat Hooded Warbler Wilson’s Warbler Canada Warbler Yellow-breasted Chat Tanagers (Thraupidae 3) Summer Tanager Scarlet Tanager Western Tanager Brush Song Sparrow Lincoln’s Sparrow Cardinals, grosbeaks, and allies (Cardinalidae 5) Rose-breasted Grosbeak Blue Grosbeak Indigo Bunting Painted Bunting Dickcissel Blackbirds and orioles (Icteridae 2) Orchard Oriole (Emberizidae 3) Savanna Sparrow TABLE 1. C Species Baltimore Oriole . 67 Proceedings of the Fourth International Partners in Flight Conference

TABLE 2. VARIATION IN CAPTURE RATES OF NEOTROPICAL MIGRANTS DURING SPRING MIGRATION AT THE PLAYA SALINAS BANDING STATION IN VERACRUZ, MÉXICO, 1999-2007.

Capture rate Year Number of species Number of families Number of individuals (mean birds day-1) 1999 51 11 503 9.5 2000 47 12 669 12.6 2001 54 13 807 15.2 2002 40 10 448 8.4 2003 54 12 1,219 23.0 2004 57 12 1,174 22.1 2005 51 10 955 18.0 2006 57 12 1,428 27.3 2007 77 12 1,323 29.1

The highest capture rates were those for comparable to those of other studies (for a sum- Least Flycatcher and Yellow Warbler, while mary, see Wang and Finch 2002). The measure the Magnolia Warbler was the species with the of relative abundance provided by our mist-net highest recovery rates. data should be interpreted with caution since mist-net samples provide a biased measure of INTERANNUAL SURVIVORSHIP abundance (Wang and Finch 2002).

PSBS has had few recaptures (in different INTERANNUAL VARIATION IN CAPTURE RATES years) of individuals banded at this station: 37 individuals of 10 species (Table 3). These indi- The variation in the capture rates for the viduals, with two or more of such recoveries, most common species is significant among show life-spans ranging 2-8 years (mean of 2.9 seasons. Although it has been suggested in years, Table 3). Noteworthy examples of these principle that capture rates can be used as a are a Magnolia Warbler that was consecutively measure of change in population levels (e.g., recaptured for six years and a Tennessee Warbler Dunn et al. 2004), we did not address the topic originally banded in 2000 and recaptured in 2007. in this paper. Simons et al. (2004) identified many elements that influence the variation in SEASONAL VARIATION IN CAPTURE RATES capture rates, such as weather rhythms, habi- tat changes and other factors. More recently, Daily capture rates peaked around the end of Hochachka and Fiedler (2008) identified that April, with smaller capture peaks during May. a trend in “trappability” can affect these esti- These “peaks” normally occurred after rainy mates. We will explore this issue in the future, days or other climatic conditions adverse for when our understanding of factors affecting migration. capture rates allows us to calculate population change using an appropriate analysis model NEW DISTRIBUTIONAL RECORDS that accounts extrinsic sources of variation.

Townsend’s Warbler and Western Kingbird VALUE OF HABITATS SURROUNDING BANDING were new regional records for the coastal region STATION AS STOPOVER HABITAT of central Veracruz.. The Townsend’s Warbler is usually found in winter in the oak-pine forest Although this paper does not cover the of the mountains whereas the Western Kingbird topic of mass gains and dietary prefer- is a resident of west and central Mexico. Both ences of migrants while using the habitats species have been recorded as vagrants in the around PSBS, our observations while banding Sierra de Los Tuxtlas region in south Veracruz migrants suggest that migrants are frequently (Howell and Webb 1995). using fruits of the two most common fruiting trees (Coccoloba humboldtii and C. barbaden- DISCUSSION sis). Many of the species captured, includ- ing some typically considered insectivores DIVERSITY AT PSBS such as wood-warblers and flycatchers, left (Coccoloba?) droppings in fabric bags, at the The diversity of species and families, and base of the nets, or in the processing station the capture rates of individuals from PSBS are while being banded. Passerine migration in Veracruz—Martínez Leyva et al. 68

TABLE 3. INTERANNUAL SURVIVORSHIP OF 37 INDIVIDUALS (10 SPECIES) OF SPRING MIGRANTS CAPTURED AT THE PLAYA SALINAS BANDING STATION IN VERACRUZ, MEXICO, 1999-2007.

Species Band number 1999 2000 2001 2002 2003 2004 2005 2006 2007 Least Flycatcher 2180-35096 0a 11000000 2190-76049 001100000 2270-35078 000010101 2350-99339 000001101 Yellow-throated Vireo 2070-98223 110000000 Gray Catbird 0941-58310 011000000 0941-58324 010011000 1411-19684 010010001 House Wren 2070-97551 010010000 Tennessee Warbler 2180-35051 010000001 2180-35883 000110000 Yellow Warbler 2110-91210 101000000 2110-91236 110000000 2110-91295 101000000 Magnolia Warbler 2110-91202 110000000 2110-91207 101000000 2110-91211 111111000 2180-35092 011000000 2180-35094 011000000 2180-35809 000101000 2180-35951 000011100 2180-35952 000011000 2180-35973 000011000 2300-75702 000011000 Ovenbird 1671-29027 000100100 1671-29030 000110000 1671-29089 000011000 1911-11703 000001100 2070-98201 110000000 Black and White Warbler 2110-91209 110000000 2270-35075 000011001 Yellow-breasted Chat 1411-19670 011000000 1411-19671 011000000 1411-19947 000010100 1411-19948 000010100 1411-19961 000011000 1711-72062 0 0 0 0 0 1 1 0 0 a 0 = individual was not captured in that year; 1 = individual was captured in that year

CONCLUDING REMARKS Since the PSBS is located in the IBA C-50 (Humedales de Alvarado), this study contrib- The results obtained from the banding at utes to our knowledge on the importance of PSBS show the importance of this site as a this area as part of this bird protection scheme. migratory stopover habitat for neotropical Besides that, Pronatura Veracruz is also increas- migrants. The diversity and abundance of spe- ing its presence with more studies of the aquatic cies banded give this site great conservation birds of this area, both migratory and resident. relevance in a landscape of steadily declining stopover habitat. ACKNOWLEDGMENTS The abundance of fruits during the pas- sage of spring migrants may also indicate that We thank Brad A. Andres for help with the birds are important dispersers for the seeds of original establishment of the PSBS. We also thank the Coccoloba and other plant species, but more our friends in the village of Playa Salinas for studies are needed in this specifi c matter to their hospitality during our fi eld work. Enrique accurately prove this hypothesis. Portilla and Gilberto Silva of the Instituto Given this loss of habitat, we hope to be able de Investigaciones Biológicas (Universidad in a near future to include this area in some cat- Veracruzana) provided logistical support in the egory of protection, either state or private, and early years of the station. Pronatura Veracruz has continue and expand our research for many received funding for our work from the USFWS more years. North American Wetland Conservation Act, 69 Proceedings of the Fourth International Partners in Flight Conference the Gulf Coast Bird Observatory, The Nature MEHLMAN, D. W., S. E. MABEY, D. N. EWERT, C. Conservancy, the Universidad Veracruzana, DUNCAN, B. ABEL, D. CIMPRICH , R. D. SUTTER, and the Fondo Mexicano para la Conservación AND M. WOODREY. 2005. Conserving stopover de la Naturaleza. Equipment for fi eld work sites for forest-dwelling migratory land- was donated by PRBO Conservation Science birds. Auk 122:1281–1290. (Borja Milá), the Institute for Bird Populations MOORE, F. R. [ED.]. 2000. Stopover ecology of (Dave DeSante), the Avian Ecology Lab of the Nearctic-Neotropical landbird migrants: University of Missouri (John Faaborg), Birder’s Habitat relations and conservation impli- Exchange (Betty Petersen), and Optics for the cations. Studies in Avian Biology, no. 20. Tropics (Joni Ellis), to whom we are also grate- Cooper Ornithological Society, Camarillo, ful for providing travel grants to the McAllen CA. Partners in Flight Conference. The operation of MOORE, F. R., S. A. GAUTHREAUX, JR., P. KERLINGER, the PSBS is made under permits from México’s AND T. R. SIMONS. 1993. 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