j. RaptorRes. 33(3):268-269 ¸ 1999 The Raptor ResearchFoundation, Inc.

STRIATEDCARACARA ( AUSTRALIS) POPULATION AT STATENAND A•o NUEVO IS•DS

ESTEBANFRERE AND ALEJANDROTRAVAINI Centrode Investigadones de Puerto Deseado, Universidad National de la PatagoniaAustral, Alte. Brown y Coldns/n, (9050) PuertoDeseado, Santa Cruz, Argentina

FundaciSnVida SilvestreArgentina, Defensa 245 6 øpiso, (1065) BuenosAires, Argentina ADRIAN SCHIAVINI CentroAustral de Investigadones Cientificas, CC 92, (9410) Ushuaia,Tierra del Fuego, Argentina

KEY Worn)s: Striated ; Phalcoboenus australis; racaras (Caracara plancus), and one Red-backed Hawk populationsim Argentina. (Buteopolyosoma) were also observedduring surveys.Stri- ated Caracaraswere the most abundant raptors account- The Striated Caracara (Phalcoboenusaustralis) is cur- ing for 59% of total observationsand were as common rently consideredto be globallyNear-threatened (Collar as Crested Caracaras in continental habitats (one individ- et al. 1994). Distributed on southern islands off southern ual for every 4.4 km; Travainiet al. 1995). South America (Narosky and Yzurieta 1987), its heavy CrestedCaracara and Turkey Vulture countsat Staten persecution on the Islas Malvinas (Falkland Islands), Island were similarto thoseobtained for the samespecies where it was believed to attack weak or stranded in Patagoniawhere linear densitieswere 40 and 14 km/ (del Hoyo et al. 1994), led to its local extinction and individual, respectively(Travaini et al. 1995). Relative •solation on the smaller islandsof the group. Its present abundancesfor the other three raptor specieswe observed statusis currently unknown and surveysare needed, es- were quite low when comparedto figuresobtained in con- pecially in the islandswhere Striated Caracarasare sup- tinental Patagoniawhere linear densitiesof Andean Con- posedlylocally numerous (del Hoyo et al. 1994). Here, dors, Grey Buzzard-Eagles,and Red-backedHawks ranged we report on the first exhaustiveStriated Caracara census between 40-60 km/individual (Don/tzar et al. 1993). conducted at Staten and Afio Nuevo islandsduring a sci- Striated Caracaraswere more abundant in our study entific surveyaimed at evaluatingthe islands'faunal con- area than in the PeninsulaMitre in Tierra del Fuego servation status (Parera et al. 1997). (Clark 1984). All the Striated Caracaraswe observed were Both islands (63 000 ha) are located at the southern at or in close proximity to coloniesof marine mammals extreme of SouthAmerica, 30 km awayfrom Isla Grande and . We observed 68 and marine mam- de Tierra del Fuego which is shared by both Argentina mal coloniesalong 196 km of coastlineat Staten and Afio and Chile acrossthe Le Maire Straits (Fig. 1). The to- Nuevo Islandscompared to only 12 coloniesalong 170 pographyof StatenIsland is rugged with a peak elevation km of coastlineat PeninsulaMitre, Tierra del Fuego (Pa- of 823 m at Monte Boveand the coastlineis highly irreg- rera et al. 1997, Schiavini unpubl. data). Differential ular with manyfiords and bays(Kfihnemann 1976). The availability of food sourcescould explain the higher Afio Nuevo Islands are a group of isletswith similar to- abundance of Striated Caracaras. Staten and Afio Nuevo pography,north of Staten Island. The weather on both Islands should be considered key areas to protect this islands is cold with a mean temperature of 6-8 and -2- geographicallyisolated raptorial species. 4øCduring summerand winter, respectively.Oceanic hu- mid winds are responsiblefor an annual rainfall of 2000 RESUMEN.--Aunqueel estadode conservaci6ndel Caran- mm (Kfihnemann 1976). cho austral (Phalcoboenusaustralis) se considera incierto, la The surveywas conducted from 12 November-9 De- fimrte persecuci6nde suspoblaciones por el hombre hace cember 1995. Counts were conducted by three experi- suponerque podria estaramenazada. Aqui describimoslos enced observersfrom a 12-m long sailboat (maximum resultadosde un censorealizado para estaespecie en Isla 110 m off the coastline), a rubber boat and ground de los Estados e Islas de Afio Nuevo (54ø45'S, 64ø98'W). searchingby foot when possible.Binoculars (10X50) and Sobre un recorddo de 196 km, el 68% de la linea de costa a 12-40X spotting scopewere used for identifica- total de las islas, se contaron 37 caranchos australes (un tion. The position of detected was obtained with a individuo cada 5.3 km). E1 carancho austml result6 ser la Global PositioningSystem (Garmin 50, GPS). rapaz mils abtmdantedel •ea estudiada,alcanzm•do sus Thirty-sevendifferent StriatedCaracaras were observed densidadesvalores similares al de poblacionesbien conser- at 12 locationsalong 196 km of coastlinesurvey (68% of vadasdel Caranchocomfin (Caracaraplancus) en •eas con- total island coastline,Fig. 1) for a linear densityof one tinenmles.La abundanciadel Carancho australregistrada caracarafor every 5.3 km. Two Andean Condors (Vultur en nuestroestudio es de las mils altas descritaspara esta gryphus),17 Turkey Vultures (Cathartesaura), one Grey especie.La cantidadde coloniasde avesy mamiferosma- Buzzard-Eagle(Geranoaetus melanoleucus), six Crested Ca- rinos presentesen las islasy la fi•erte asociaci6nde la es-

268 SEPTEMBER1999 SHORT COMMUNICATIONS 269

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Figure 1. The locationof Statenand Afio NuevoIslands. The dottedline showsthe coastlinethat wassurveyed. pecie con estascolonias, parecen ser las causasdel buen DON,•ZAR,J.A., O. CEBALLOS,A. TRAVAINIAND F. HIRALDO estadode conservacitnde la poblacitn de Caranchoaus- 1993. Roadsideraptor surveysin the Argentinean Pa- tral. Isla del los estados e Islas de Afio Nuevo deben ser tagonia.J. RaptorRes. 27:106-110. consideradascomo fireasprioritarias para la conservacitn DEE HOYO,J., A. ELLIOT ANDJ. SARGATAL.1994. Hand- de estaespecie. book of the birds of the world. Vol. 2. Lynx Editions, [Traducci0n de Autores] Barcelona,Spain. ACKNOWLEDGMENTS KOHNEMANN,O. 1976. Observacionesecoltgicas sobre la We acknowledgeFundacitn PatagoniaNatural and the vegetacitn marina y terrestre de la Isla de los Estado Wildlife ConservationSociety and by National Geograph- (Tierra del Fuego, Argentina). Ecosur3:121-248. ic Society (Grant 5548/95) for financial support, and NAROSKY,T. ANDD. YZURIETA.1987. Gula para la idenn- thankJulio Brunet, SergioBalbino and Alejandro Chiz- ficacitn de las avesde Argentina y Uruguay.Vfizquez zini for their help in the field work.Javier Bustamante, Mazzini Editores, BuenosAires, Argentina. Miguel Delibes,David Martinez, and FabifinJaksic pro- PARERA,A., A. SCHIAVINIAND E. FRERE.1997. Relevamien- dded helpful commentson the manuscript. to ecoltgico de la Isla de los Estados.Tech. Bull. No. LITERATURE CITED 38, Fundacitn Vida SilvestreArgentina, BuenosAires, CLAm;, R.R. 1984. Notas sobre aves de Peninsula Mitre, Argentina. Isla Grande de Tierra del Fuego, Argentina. Hornero TRAVAINI,A., A. RODRiGUEZ,O. CEBALLOS,J.A. DON,•ZAR 12:212-218. ANDE HIRALDO.1995. Roadsideraptor surveysin cen- COLLAR,N.J., M.J. CROSBYAND A.J. STATTERSFIELD.1994. tral Argentina, 1995. Hornero14:64-66. Birds to watch 2. The world list of threatened birds. Birdlife International, Cambridge, U.K. Received29 August 1998; accepted13 March 1999