J. Field Ornithol., 68(1):79-90 RECOVERIES OF ROSEATE AND COMMON TERNS IN SOUTH AMERICA HELEN HAYSAND JOSEPH DICOSTANZO Great Gull Island Project AmericanMuseum of Natural History Central Park West at 79th Street New York, New York 10024 USA GRACE CORMONS 26201 Dennis Road Parksley,Virginia 23421 USA PAULO DE TA_v,so ZUQUIM ANTAS SON 408 Bloco 8 Apt 112 Brazilia DF 70856-010 Brazil jo3•o Luis XAVIERDO NASCIMENTOAND IN•S DE LiMA SERRANO DO NASCIMENTO Biologo/Cemave Caixa Postal04/34-Cep 70312-970-BsB-CF Brazil RICARDO ESTEBAN BREMER FundacionVida SilvestreArgentina EstacionBiologica Punta Rasa C. C. No16 7105 San Clementedel Tuy•i Argentina Abstract.--DuringFebruary and early March of 1995, Great Gull Island Projectresearchers surveyedthe coastsof northern Argentina,Uruguay, and Brazil for winteringRoseate (Sterna dougallii) and Common (Sterna hirundo) Terns. We sightedboth specieson 6 March in a smallflock off Alcobaga(17ø33'S, 39ø4'W) near Porto Seguro.This sightingof Roseatesand the report of the recoveryof a Great-Gull-Island-bandedRoseate Tern at 18ø00'S,39ø30'W on 24Jan. 1995 provide the southernmostwintering records of the speciesto date.At Punta Rasa,Argentina, we found an estimated20,000 to 30,000 Common Terns in early February. Although the speciesknown range includesArgentina, this is the first report of sucha large winteringconcentration at thislatitude. All color-bandedCommon Terns we sawin Argentina and southern Brazil, as well as all recovered banded birds from these areas, were over one year old. This suggeststhat older CommonTerns occupythe more southernparts of the wintering range. Recoveriesof Great Gull Island Common Terns from southernBrazil and Argentinamade in April and May, and subsequentlytrapped on Great Gull Island,show that somebirds make the >8000 km trip in 3 wk or less. 79 80] H. Hayset al. J.Field Ornithol. Winter 1997 RECOBRO DE INDMDUOS DE STERNA DOUGALIJIY S. HIRUNDO EN SUg a•gIC• Sinopsis.---Duranteel mes de Febrero y los primerosdias de Marzo de 1995, los investiga- dores del ProyectoGreat Gull Island visitaronlas costasde Argentina, Uruguay,y Brasilen buscade registrosde inviernopara el GaviotinRosado (Sterna dougallii) y el GaviotinComfin (S. hirundo).Ambas especies fueron observadasen pequefiascolonias en la costade Alcobaca (17ø33'S,39ø04'W), cerca de Porto Seguroel dia 6 de Marzo. Los avistamientosde Gaviotin Rosado,junto con la recapturade un individuo de GaviotlnRosado anillado en la isla Great Gull el 24 de Enero de 1995, representanlos registrosinvernales mits australespara esta especie.Durante los primeros dias de Febrero se calcula haber obervadoentre 20,000 a 30,000 individuosde Gaviotin Comfin en Punta Rasa,Argentina. Afin cuando las costas Argentinashan sido consideradascomo parte de la distribuci0nnormal de S. hirundo,este es el primer reporte de la existenciade grandescolonias invernales en estalatitud. Todos los individuosde GaviotlnComfin con bandasde coloresobservados en Argetina y sur de Brazil,as/como todaslas recapturas realizadas en estasitreas de avesanilladas en la islaGreat Gull, fueron mayoresde un afio de edad. Esto sugiere,que las avesde mayor edad ocupan la parte mits australdel rango invernal de distribuci6n.Las recapturashechas en Abril y Mayo de Gaviotln Comfin provenientesde la isla Great Gull en el sur de Brasily Argentina, prueban que algunasde estasaves son capacesde realizar un viaje de 8000 km en tan solo tres semanas o menos. The major wintering areasof RoseateTerns (Sternadougallii) and Com- mon Terns (Sterna hirundo) in the Western Hemisphere are poorly known. Murphy (1936) reported six Roseate Terns collected by Rollo Beckoff Salvador,Bahia, Brazil on 28 Apr. 1916.Hays (1971) reporteda recovery of a RoseateTern from Gorgona Island off the Pacific Coast of Colombia on 27 Oct. 1969, 24 d after the bird was observed on the coast of Connecticut. Hamilton (1981) summarized wintering ground recov- eries of Roseate Terns banded on Great Gull Island, New York ranging along the northern coastof South America to eastern Brazil. Lara-Resen- de and Leal (1982) report RoseateTern recoveriesalong the Brazilian coast.Nisbet (1980, 1984), using United StatesNational BiologicalSurvey (USNBS) recordsfrom all banders,defined the wintering range of Ro- seateTerns as falling between 11øNand 13øS. Common Terns have been reported to winter over a much wider range than Roseate Terns. On the Atlantic coast birds winter from the West Indies to Argentina and on the Pacific coastfrom southern California to Chile (AmericanOrnithologists' Union 1983,Bull 1974).Austin's (1953) analysisof banding recoveriesof Common Terns banded along the At- lantic coast of North America showed these terns wintered from the southern West Indies to southern Brazil, with most of the recoveries fall- ing along the northeastern coastof South America north of the Amazon. Bull (1974) and DiCostanzo(1978) also reported recordsof Common Terns from Bolivia and the interior of Brazil. Recovery data for Common Terns along the coast of Brazil show an increase in recoveriessince the founding of Centro de Pesquisespara Conserva•:5odos Aves Silvestres(CEMAVE), the Brazilian banding orga- nization,in 1979 (Lara-Resendeand Leal 1982). Their mapsshow recov- eries of Common Terns from northern Brazil,just south of the mouth of the Amazon, to Lagoa do Peixe, Rio Grande do Sul in southern Brazil Vol.68,1•o. 1 Roseateand CommonTerns in SouthAme•ca [81 where they report three recoveriesof terns banded in the northeastern United States.Harrington et al. (1986) found two terns originallybanded on the Atlantic coastof the United Statesamong twenty-fivebirds netted at Lagoa do Peixe in 1984. In southern Brazil, Lara Resende (1988) re- ported approximatenumbers in concentrationsof Common Terns at La- goado Peixe, (between31ø26'S, 51ø10'W and 31ø14'S,50ø54'W) in 1986- 1987: October 100, November 7000, December 10,000,January 13,000, February 8000, March 2000, April 500. In recognition of its importance to terns and shorebirdsthe Brazilian governmentdeclared Lagoa do Peixe a national park on 6 Nov. 1986 under the jurisdiction of Instituto Brazileiro do Meiombiente e dos Recursos Naturais Renovfiveis (IBAMA) (Lara Resende1988). The Brazilian government has supportedbanding at Lagoa do Peixe from 1984 through 1995, first through CEMAVE and then through CEMAVE/IBAMA Analysisof band recoverieshas given us a good idea of which months Roseateand Common Terns spend on the wintering ground and which monthsthey spendmigrating (Austin 1953; Haymes and Blokpoel1978; Nisbet 1980, 1984). Preciselywhere the majority of Roseateand Common terns spend the winter is a different question.There are no data in the literature that show where Roseate Terns spend the period January- March. There havebeen a few studiesof Common Ternson the wintering ground (Blokpoelet al. 1982, 1984, 1987, 1989; Erwin et al. 1986;Har- rington et al. 1986; Lara Resende 1988). These studiesreport groups of Common Terns ranging from 200-2600 in Trinidad, up to 13,000 at La- goa do Peixe, and about 800 off the coastof Peru. In addition,A. South- worth read color combinationsof six birds among 300 to 350 Common Terns on a beach about two hours north of Salvador, 18-21 Feb. 1987 (A. Southworth, pers. comm.). RoseateTerns were declaredendangered in North America in 1987, and their new statusunderlined the importance of both breeding and wintering ground studies.While searchingfor RoseateTerns in South America we hoped to seecolor-banded Common Terns aswell asRoseates originally banded on Great Gull Island, New York to determine specifi- cally where Great Gull Island birds wintered. In February and March 1995, members of the Great Gull Island Project conducted a survey of coastaland off-shoreareas in Argentina, Brazil, and Uruguay looking for Roseateand Common Terns. This paper presentsthe resultsof that sur- vey and an analysisof recoveriesof banded birds. STUDY AREA AND METHODS Participantsin the South American coastalsurvey were Helen Hays, JosephDiCostanzo, Grace Cormons,Peter Cormons,and Mauricio Calvo. DiCostanzoand Hays were responsiblefor retrieval and analysisof band- ing recoverydata. Through the USNBS Bird BandingLaboratory Paulo T. Z. Antas, Jofio Luis X. do Nascimento, and InCesS. do Nascimento contributedbanding information from Lagoado Peixe in southernBrazil. 82] H. Hayset al. J.Field Ornithol. Winter 1997 Esteban Bremer provided recovery data on terns he has netted at Punta Rasa since 1993. The color-banded Common Terns we saw in South America were all birds banded on Great Gull Island, New York (41ø12'N, 72ø07'W). Each seasonsince 1969 teamsof studentshave made daily checksof Great Gull Island marking nests,banding chicks,and trapping adults (Cooper et al. 1970, Hays and Riseborough1972). Adults of both speciesare given in- dividual color-band combinations (DiCostanzo 1980). Over a third of the 3000 adult Roseateand 90% of the 16,000adult CommonTerns nesting on Great Gull Island have been banded. Migration routesfor both Common and Roseateterns have been traced through recoveriesof banded birds reported to the USNBSBird Banding Laboratory. We have included in Tables 2, 3, and 4 recoveriesof birds banded under Hays'sbanding permit (1020 Common Tern, 163 Roseate Tern) as well as those banded by the late Gilbert Cant (2 Common), Donald Cooper (36 Common, 26 Roseate), Matthew Cormons (8 Com- mon), David Duffy (21 Common, 2 Roseate), the late Thomas Davis (29 Common), Catherine Pessino (8 Common, 1 Roseate), the late Gilbert Raynor (68 Common), the late