168 SHORT COMMUNICATIONS VOL. 38, NO. 2

1986. Is long-distancemigration possiblefor soaring ferences in the stopoverof fall landbird migrants on hawksusing only storedfat? Auk 103:607-611. the coast of Alabama. Auk 114:695-707. SPAA•,R. 1997. Flight strategiesof migratingraptors: a YOSEF,R. 1996. Raptors feeding on migration at Eilat, comparative study of interspecific variation in flight Israel: opportunisticbehavior or migratory strategy?J. characteristics. Ibis 139:523-535. RaptorRes. 30:242-245. SPSS, INC. 1997. SYSTAT© 7.0: Statistics. SPSS, Inc., Chi- cago, IL U.S.A. WOODREY,M.S. ANDER. MOORE.1997. Age-relateddif- Received21 June 2003; accepted28 December 2003

j. RaptorRes. 38(2):168-174 ¸ 2004 The Raptor ResearchFoundation, Inc.

SPANISHRINGING AND RECOVERYRECORDS OF BOOTED (HIERAAETUSPENNATUS)

IGNACIO S. GARCIA D•OS • Institutode Investigacidnen RecursosCineggticos (C.S.I.C.-U. C.L.M.), Rondade Toledos/n, 13005 CiudadReal, Spain

KEYWORDS:; Hieraaetus pennatus; mortality; and Bildstein 2000). However,little is known for this spe- longevity;philopatty. cies about the routes used during migration to Africa, wintering areas,use of stop-oversites during migration, Scientific ringing is a useful method to studymany as- habitat use in wintering areas,threats outside the breed- pectsof the life history of , and is especiallyimpor- ing season,where first-yrbirds spend their secondsum- tant for the study of migration. Information about mi- mer, and philoparry. This paper presentsa first analysis gratory routes and wintering areasof raptorsis necessary of ringing and recoveryrecords of this speciesin Spain for understanding the factors affecting the conservation for mortality rates, migratory routes, dispersal move- of these speciesoutside the breeding areas,such as hab- ments, and longevityin the Booted . itat loss, environmental contamination, or human inter- ference (Zalles and Bildstein 2000). This is particularly METHODS relevant for raptor speciesthat perform long migratory Ringing data presented in this paper were obtained journeys, which may be especiallyvulnerable to human from the Ringing Office of the Spanish General Direc- •mpacts.Furthermore, the concentrationof a large num- tion of Nature Conservation.These include only recov- ber of individualsduring migration increasesthe poten- eries of Booted Eaglesringed in Spain. From 1973-99, 2080 were marked with metal rings in tial for natural and antropogenicimpacts such as shoot- Spain (Hernfindez-Carrasquillaand G6mez-Manzanaque •ng and trapping (Zalles and Bildstein 2000). 2000), of which 80 have been recovered (as of 2001). For The Booted Eagle (Hieraaetuspennatus) breeds in this analysis,the recoveryrecords have been divided into southern Europe and winters in Africa (Cramp and Sim- four periods: (1) breeding, 15 March-14 September;(2) mons 1980). In winter, Booted Eagles breeding in Eu- post-nuptialmigration, 15 September-14 November (15 rope may move southward into the area where Booted d before of the peak passagethrough the Gibraltar Strait Eaglesnest in southernAfrica (Brooke et al. 1980, Peplet until the beginning of the wintering period; Bernis et al. 2001, D. Peplet and R. Martin unpubl. data). There 1973); (3) winter, 15 November-14 February (Bernis are some data on the numbersof Booted Eaglescrossing 1980); and (4) pre-nuptial migration, 15 February-14 the Gibraltar Strait (Bernis 1973, Garz6n 1977, Cramp March (only one case that has not been included in the analyses). Eagles were classifiedinto one of three age and Simmons 1980, Finlayson1992, Zalles and Bildstein classes:juveniles (<1 yr), immature (2-3 yr), and adults 2000), the MessinaStrait (Thiollay 1989, Zalles and Bild- (>3 yr; Newton 1979, Cramp and Simmons1980). ste•n2000), the westernPyrenees (Iribarren 1973, Zalles and Bildstein 2000), the Bab-el-Mandeb Strait (Welch RESULTS AND DISCUSSION and Welch 1989, Zalles and Bildstein 2000), and other Causesof Recovery.From 80 Booted Eaglesringed in localities during post-nuptialmigration to Africa (Zalles Spain and subsequentlyrecovered, 58.8% were found dead, 18.8% were found alive and immediatelyreleased, Present address:Plazuela del Padre Felipe Fernfindez and 13.8% were found alive but were not released due nø 1-2 ø, 05416, EL ARENAL/rvila, Spain; e-mail address: to their poor physicalcondition. No detailed information [email protected] could be obtained for the remaining 8.8% of ringed ca- JUNE2004 SHORTCOMMUNiCATiONS 169

,Jr Ringingand recoveryin Mao (Menorca);distance = 0 km (N= 1). ß Ringingand recovery in Almonte (Huelva); distance =2 km(N= 1), 6 km (N = 3) and 30 km (N = 1). ß Ringingand recovery in Do•anaNational Park (Huelva); distance= 0 km (N= 6) and 27 km (N= 1). Morocco Faso Algeria& Ringingandrecovery inMadrid; distance =7 km (N= 1), (N=2) Morocco 11km (N= 1) and 19 km (N= 1), Figure l. Ringing and recoverylocalities during breeding period (15 March-14 September) of Booted Eagles marked in Spain. Recoveriesof birds that were ringed during the samebreeding seasonwere excluded.

gles.The percentageof birds found dead wasgreater for juvenilesand iramatures(combined; 72%, N = 50) than for adults (36.7%, N = 30). This difference was statisti-

25 cally significant(Yate's corrected X '• = 8.26, P = 0.01). year11-3 years•l> 3 yearsI This is consistent with the pattern that young raptors tend to have higher mortality rates than adults (Newton 20 1979). Causesof mortalitywere: shooting(21.3%), drowning (14.9%), collision with electric powerlinesor electrocu-

,o tion (8.5%), trapping (6.4%), general trauma (6.4%), H 10 poison (4.3%), predation by other raptors (2.1%), pre- dation by other wild (2.1%), collisionwith cars •2 (2.1%), and unknown (31.9%). 2-- 2 Causesof mortality in juvenileswere largelyrelated to 2 human activities(drowning 29.2% and shooting20.8%). The inexperience of juveniles may explain the high num- 0-49 km. 50-99 km. > 99 kin. ber of individuals found drowned (Newton 1979), as this Distance of Ringing Locality (km) canse of mortality was never recorded for adult birds. Figure 2. Distributionof dispersaldistances of Booted The primary cause of mortality for adults was shooting Eaglesfrom their natal place during breeding season,ex- (27.3%), which was also common for jnveniles (20.8%) cluding data of birds ringed and recovered during the and among iramatures (20.0%). Thus, illegal killing same breeding season seemsto be a significantmortality factor for this species, 170 SHORT COMMUNIGATIONS VOL. 38, NO. 2

Figure 3. Ringing and recoverylocalities (filled circles) during autumn migration (15 September-14November) of Booted Eaglesmarked in Spain. Recoverieswithin Balearic Islands,where the speciesis sedentary,have been ex- cluded.

including within Spain,where illegal predator control is va). The first was trapped after 184 d in Nigeria (3110 still an important conservationproblem (Villafuerte et al. km). The second was found predated by a raptor 503 d 1998). later in Togo (2980 km). The third was found dead 546 With respect to those birds found alive and immedi- d later in Mali (2708 km). ately released, the circumstancesof the recovery were Philopatry. To study dispersaldistances after the first trapping (40.9%), found insidebuildings (13.6%), found wintering season,I selectedthe recoveryrecords made with general trauma (9.1%), or found chilled (4.5%). during the breeding season, excluding the records of Among the birds found alive, but not immediately re- birds ringed and recovered during the same breeding leased,36.4% had generaltrauma, 27.3% were exhaust- season. Of the 32 selected records, 24 (75.0%) were ed, 9.1% had been shot, 9.1% had collided with electric made at a distanceless than 100 km from the birthplace powerlines, and the causeswere unknown for the re- (Fig. 1). Seven of these recordswere made at the same maining 18.1%. There were sevenrecords with no infor- locality where the birds were ringed (six adults and one mation about the recovery. younger than one yr). Raptors tend to be philopa- Dispersal Distances. The longest distances between tric, whereby young birds tend to return to natal areas ringing and recoverylocations for Booted Eaglesmarked when they reach breedingage (e.g., Newton 1979, New- in Spain were recorded for birds wintering or migrating ton et al. 1994, Forero et al. 2002), and my resultssup- in sub-SaharanAfrican countries. The greatest distance port this for Booted Eagles.With respectto young and record wasfor an eagle ringed in Alava (northern Spain) immature individuals, 57.1% were recovered between and recovered after 1093 d in Burkina Faso (3530 km). 0-100 km of their birthplace. This suggeststhat even Three other records corresponding to long migration young, nonbreeding birds may return to their natal areas journeys were of nestlingsringed in Murcia (southeast- during the next breeding season.However, there are sev- ern Spain) and Dofiana National Park (province of Huel- en casesof Booted Eaglesyounger than 1 (N = 5) and JUNE2004 SHORTCOMMUNICATIONS 171

Italy

Algeria

3•' Ringingand recoveryin DofianaNational Park (Huelva); distances= 0 km and 6 km (N = 2). 1 Ringingand recovery in L'Albufera(Valencia); distance: 0 km (N= 1).

Nigeria )rocco Togo

Figure 4. Ringing and recovery localities during winter (15 November-14 February) of Booted Eagles marked in Spain. Recoverieswithin Balearic Islands,where the speciesis sedentary,have been excluded.

2-yr old (N = 2) recoveredvery far from their birthplace excluded), I obtained a picture of the migration routes during the following breeding season (locations of re- for the Spanishpopulation (Fig. 3). The recordsavailable coverieswere Algeria, Burkina Faso,Mali, and Morocco). showed one movement east-northeastof ringing areas The recovery distances were significantly different (Cficeres),two south-southeastof ringing areas (C/tdiz), among age classes(ANOVA with log-transformed dis- and one recovered south-southwestof the ringing area persal distances;F2,29 = 3.9, P = 0.035; Fig. 2), and this (Murcia). Recovery made at east-northeastcould be due suggeststhat probably young eaglestend to dispersefur- to a pre-migratory movement of bird looking for a more ther from their natal area than iramatures or adult birds productive site during summer months, or perhaps rep- during breeding season.In other raptors, the proportion resented a bird exploring possiblefuture breeding areas of individuals found near their natal areas increase with (Newton 1979, Olea 2001). age, and young dispersegreater distancesin the breeding Wintering Areas. Booted Eagles recovered between 15 season (Newton 1979). November and 14 February should reflect wintering ar- Longevity.The longevityrecord in the wild was a bird eas used by the Spanish population (Fig. 4). I selected ringed as a nestling in the province of Madrid (central 14 records, which can be divided into five groups: two Spain) and recovered dead in a nearby area almost 14-yr eaglesrecovered east-northeastof ringing areas (Barce- later (5084 d-old). A 4638 d-old Booted Eagle ringed in lona, Spain; Firenze, Italy), five individuals recovered in the province of Huelva was also recovered in the Kheni- Africa during winter (Morocco, Togo, Mali, Algeria, and fra (Morocco). Nigeria; Fig. 5), one sedentary individual (Valencia, Migration Direction. By using only Booted Eagles Spain), five birds wintering in southern Spain (Cfidiz, ringed and recovered in the same season(the records of Huelva, Sevilla), and one bird wintering in central Spain the sedentary population in Balearic Islands have been (Madrid). 172 SHORT COMMUNICATIONS VOL. 38, No. 2

• ß Algeria

Mali

ß

Nigeria

* Recovery duringbreeding period. ß Recoveryduring winter period.

Figure 5. Recoverylocations of Booted Eaglesduring breeding and winter periods in Africa. JUNE2004 SHORTCOMMUNICATIONS 173

Winter recoveriesat east-northeastbreeding areaswere LITERATURE CITED surprising, becauseBooted Eagles generally are known BERN•S,E 1973. Migraci6n de Falconiformesy Cicoma to fly south from Europe to Africa (Brown and Amadon spp. por Gibraltar, Verano-Otorio 1972-73. Primera 1968, Grainp and Simmons 1980) similar to other Euro- Parte. Ardeola 19:151-224. pean migratory raptors (Gonzalez and Merino 1990, ß 1980. La migraci6n de las avesen el Estrecho de Gonzalez 1991, Donftzar 1993, Triay unpubl. data). These Gibraltar. Vol. 1, Avesplaneadoras. Universidad Com- two winter localities for Booted Eagles, Barcelona and plutense, Madrid, Spain. Firenze, are on the Mediterranean coast, where the mild BROOKE,R.K., R. MARTIN, J. MARTIN, AND E. MARTIN winters could support a high densityof passerinesand a 1980. The Booted Eagle, Hieraaetuspennatus, as a relatively high winter activityof reptiles. Passerinesand breeding speciesin South Africa. Gerfaut70:297-304. reptiles are among the main prey of breeding Booted BROWN,L. ANDD. AMADON.1968. Eagles, hawks,and fal- Eaglesin Spain (I. Garcia Dios unpubl. data). Sunyerand cons of the world. Country Life Books, London, U.K. Vifiuela (1996) and Martinez and Sftnchez-Zapata(1999) CRAMP, S. AND K.E.L. SIMMONS. 1980. The birds of the previouslysuggested that severalraptor speciesare more western palearctic. Vol. II. Oxford Univ. Press, Ox- frequentlywintering in Mediterranean areasover the last ford, U.K. 20 yr, instead of migrating to Africa. These two Booted DONAZAR,J.A. 1993. Los Buitres Ib6ricos:biologia y con- Eagle recordsare consistentwith this suggestion.Despite servaci6n.J.M. Reyero, Madrid, Spain. the lower winter recovery of Spanish Booted Eagles in FINLAYSON,C. 1992. Birds of the Strait of Gibraltar. T. & Africa than in Europe, the primary winter quartersfor A.D. Poyser,London, U.K. the speciesis Africa (Brown and Amadon 1968, Cramp FORERO,M., J.A. DON•.ZAR,AND F. HIRALDO.2002. Causes and Simmons 1980). This is clearly supported by the and fitnessconsequences of natal dispersalin a pop- large numbers of birds crossingthe Strait of Gibraltar ulation of Black Kites.Ecology 83:858-872. (Bernis 1973). The higher recoveryfrequency in Europe GARZON,J. 1977. Birds of prey in Spain, the present s•t- in this analysiswas likely due to higher reporting rates in uation. Pages159-170 in R.D. Chancellor [ED.], Pro- Europe, and not becausemore eagleswere wintering in ceedingsof the World Conference on Birds of Prey, Europe. Vienna, 1975. International Council for Bird Preser- vation, Cambridge, U.K. RESUMEN.--En este articulo presentamos una aproxima- GONZXLEZ,J.L. ANDM. MERINO.1990. E1 Cernicaco prim- ci6n sobre la mortalidad, migraci6n, dispersi6n,y lon- illa (Falco naumanni) en la Penfsula Ibdrica. ICONA, gevidaddel aguililla calzada (Hieraaetuspennams) basfin- Madrid, Spainß donos en las recuperaciones de individuos de esta GONZkLEZLOPEZ, J.L. 1991. E1 Aguilucho Lagunero Cir- especie marcados con anillas metfdicas.Los resultados cusaeruginosus (L., 1748) en Esparia:situaci6n, blol- sugieren que losj0venes tienen una tasa de mortalidad ogfa de la reproducci6n, alimentaci6n y conservacl6n relativamentealta, en especialdebido a su inexperiencia, Ministerio de Agricultura, Pesca y Alimentaci6n y que el tiroteo ilegal sigue siendo una causade mortal- IGONA, Madrid, Spain. idad importante. Los j0venes tienden a dispersarsema- HERN•,NDEZ-CARRASQUILLA, F. AND A. GGMEZ-MANZA- yores distanciasque los individuos adultos, aunque en NAQUE.2000. Informe sobre la camparia de anilla- general se observauna clara tendencia filopfttrica. Se re- miento de avesen Esparia. Ecologia14:291-330. gistran movimientospremigratorios e invernada en lati- IRIBARREN,J.J. 1973. Observaci6ny recuento de rapaces. Vida Silvestre 12:260-265. tudes mfts norterias que las de reproducci6n, lo que puede estar relacionado con una tendencia creciente a MARTiNEZ,J.E. ANDJ.A.S/•d•CHEZ-ZAPATA. 1999. Invernada la sedentarizaci6n en el Mediterrfmeo. La maxima lon- del Aguililla Calzada (Hieraaetuspennatus) y Culebrera Europea (Circaetusgallicus) en Espafia. Ardeola46:93- gevidadregistrada pot este m6todo es de 14 aftos. 96. [Traducci6n del autor] NEWTON,I. 1979.Population ecology ofraptors. T. & A D ACKNOWLEDGMENTS Poyser,London, U.K. , P.E. DAVIS,AND D. Mossß 1994. Philopatry and I thank my wife for her support of my work and for population growth of Red Kites, Milvus milvus,Walesß cheering me up during the difficult timesof my Doctoral Proc. R. Soc. Lond. 257:317-323. dissertation. I also appreciate the support of Manuel OLE^, P. 2001. Postfledging dispersalin the endangered Garcia Tornero, Javier Murioz Familiar, and Marcos Gon- LesserKestrel Falco naumanni. Bird Study48:110-115. zalez Jim6nez. The Ringing Office of the Spanish Gen- eral Direction of Nature Conservation provided ringing PEPLER,D., R. MARTIN,AND HJ. VAN HENSBERGEN.2001 and recovery data. I would also like to thank Juan Go- Estimatingthe breeding population of Booted Eagles mendio for reviewing the English version of this manu- in the Cape Province, South Africa. J. RaptorRes. 35. script. David Pepler,Javier Viriuela, and two anonymous 15-19. refereesmade useful commentson previousdrafts. SUNYER,C. ANDJ. VIlC,IUELA. 1996. Invernada de rapaces 174 SHORT COMMUNICATIONS VOL. 38, No. 2

(0. falconiformes)en Espafia Peninsular e Islas Bale- crash in a game species:the case of Red Kites and ares. Pages 361-370 in J. Muntaner and J. Mayol rabbits in Spain. Biol. Conserv.84:181-188. lEDS.], Biologiay ConservaciCnde las rapacesMedi- WELCH, G. AND H. WELCH. 1989. Autumn migration terr/meas, 1994. Monografias No. 4. SEO, Madrid, acrossthe Bab-el-MandebStraits. Pages 123-125 in B.- Spain. U. Meyburg and R.D. Chancellor lEDS.], Raptorsin THIOLLAY,J.-M. 1989. Distributionand ecologyof palearc- the modern world: proceedingsof the world confer- tic birds of prey wintering in west and central Africa. ence on birds of prey and owls.World Working Group Pages95-109 in B.-U. Meyburg and R.D. Chancellor on Birds of Prey and Owls, Berlin, Germany. [EDS.],Raptors in the modern world: proceedingsof ZALLES,J.I. AND K.L. BILDSTEIN(EDS.). 2000. Raptor the world conference on birds of prey and owls. watch: a global directory of raptor migration sites. World Working Group on Birdsof Preyand Owls,Ber- BirdLife International, Cambridge, U.K. and Hawk lin, Germany. Mountain Sanctuary,Kempton, PA U.S.A. VILLAFUERTE,R., J. VIIqUELA,AND J.C. BLANCO.1998. Ex- tensive predation persecution causedby population Received27 November2001; accepted20 June 2003

j RaptorRes. 38(2):174-177 ¸ 2004 The Raptor ResearchFoundation, Inc.

DIET SHIFT OF BARN OWLS (TrTO ALBA)AFTER NATURALFtRES IN PATAGONIA,ARGENTINA

MERCEDESSAHORES AND ANA TREJO• CentroRegional Bariloche, Universidad Nacional del Comahue,8400 Bariloche,Rio Negro,Argentina

KEYWORDS: Barn Owl; Tyto alba;fire perturbations;dietary nated by bunchgrasses(Stipa speciosa),cushion bushes sh•ft;,Patagonia. ( Mulinum spinossum),and scattered bushes (Fabiana im- bricata,Discaria articulata, Maytenus chubutensis, and Ber- berisbuxifolia). At times, low trees (D. chacaye)form small- The Barn Owl (Tyt0 alba) is broadly distributedin Ar- gallery forests.Mean annual temperatureis 8øC,and gentina and is found in severaltypes of habitatssuch as mean annual rainfall is 800 mm (Paruelo et al. 1998). woodlands,grasslands, and semideserts(Canevari et al. Diet of Barn Owls was studied from autumn-spring 1991). Barn Owls feed primarily on small mammals, al- 1998 by analyzingpellets collected seasonally under two though prey speciesdiffer slightlyamong different local- roosts(likely including 1-2 owl home ranges).We divid- roes even in the same geographicregion (e.g., in Pata- ed the yr into seasons:summer (December-February), gonia see Travaini et al. 1997, Pillado and Trejo 2000), autumn (March-May), winter (June-August), and spring which implies that owlsshow considerableplasticity and (September-November).In the Austral summer 1998- are opportunistpredators, capturing the most abundant 1999, the area wasaffected by successivenatural fires that or vulnerable prey. destroyedmost of the vegetation and left large patches In this studywe describethe diet compositionof Barn of bare soil. The owls abandoned the known roosting sites,but did not leave the area. We continued collecting Owls in a locality where the type of vegetation (and the pellets in the summer and autumn 2000, after finding associatedsmall fauna) changed drasticallyafter succes- new roostsin an unburned area adjacent to the burned sive natural fires in the area. Our objective is to record patches and not far from the abandoned roosting sites any changein prey use before and after the fires to assess (ca. 300 m). the impact of this disturbanceon the owls' feeding be- Pellets were air dried and dissected using standard havior. techniques(Marti 1987). Prey remains in pelletswere identified using keys (Pearson1995) and by comparison METHODS with reference collections.Mammalian prey were classi- The study site was located in northwestern Patagonia fied to speciesand quantified by counting skulls and (41ø03'S, 70ø59'-71ø00'W, 900 m above sea level). The mandible pairs. Birdswere identified to family level and area is a transition between the arid Patagoniansteppe quantified by counting skulls,while insectswere classified to the eastand the humid Nothofagusforests to the west. to order and quantified by counting head capsulesand The area is mountainouswith rockyoutcrops (with caves mandibles. used by owls for roosting), and the vegetationis domi- Biomassof each prey categoryin the total biomassof the diet was calculatedby multiplying mean body mass of individualsby the number of individualsin pelletsand E-mail address: [email protected] expressedas a percent of total prey biomassconsumed.