SHORT COMMUNICATIONS j. RaptorRes. 32(4):312-314 ¸ 1998 The Raptor ResearchFoundation, Inc.

HABITAT USE OF CROWNEDEAGLES (HARPYHALIAETUS CORONATUS) IN THE SOUTHERNLIMITS OF THE SPECIES' RANGE

M. ISABELBELLOCQ, STELLA M. BONAVENTURA,FAVIO N. M.ARCELINO AND M.AR•A SABATINI Departamentode CienciasBioldgicas, FCEN-Universidad de BuenosAires, Ciudad UniversitariaPab. 2 Piso4, BuenosAires 1428, Argentina

K•Y WO•,DS: CrownedEagle;, Harpyhaliaetus coronatus; Becausewe expected the Crowned Eagleto be difficult habitatus•, Argentina. to see, we conducted both road surveysand interviews with local farmers to locate eagle roostingareas. Addi- The breeding range of the Crowned Eagle (Harpyhal- tionally, staff at the Lihue Calel National Park was in- zaetuscoronatus) is limited to semi-openwoodlands in low- structed to look for and report any encounter with lands and moderate altitude mountain rangesof Argen- CrownedEagles. Road surveyswere conductedalong six una, Bolivia, Brazil, Paraguay,and Uruguay). It is a 50-km transects,completing one observationstop of 5 large-sized,open country raptor that eatsa varietyof ver- min every 0.8 km (Fuller and Mosher 1987). Surveys were performed by the sameobservers, during 18-24 No- tebrateprey species.There are over 112 sightrecords for vember 1996 from 600-1300 H. A total of 20 farmers the species,most of them from Argentina over the past were interviewed.We askedthem whether they had seen 50 years,including relativelyrecent encountersin Lihue Crowned Eagles.If the answerwas yes, we askedfor a Calel (province of La Pampa) in the southern limit of description of the animal. If the description fit a the species'range (Collar et al. 1992, De Lucca 1992 and CrownedEagle, we proceededto fill out a questionnaire 1993). Basedon this, it appearsthat the Crowned Eagle askingthe followingquestions: (1) When did you seethe mainly occursin the northcentralpart of the country,in eagle?;(2) Where did you see it?; (3) In what type of open woodlands and savannas.Three nests have been habitat?;(4) From where did you seethe eagle?;(5) Was describedin Argentina. All contained a single egg (Giai the eagle dead or alive?;and (6) What wasthe eagledo- 1952, de la Pefia 1992). The Crowned Eagle has been ing?After completing the questionnaire,we askedfarm- protected in Argentina since1954 and in Brazil it is listed ers to bring us to the exact locationswhere eagleswere as a Threatened Species(Chebez 1994). Little is known, observed.The followingvariables were recordedin 1-ha however, about its ecology and behavior (Collar et al. squareplots centered on the points where eagleswere 1992, Salvador and Eroles 1994, Gil et al. 1995). seen: habitat type, number of vegetation strata, canopy Here, we provide new information on the Crowned cover,canopy height, dominant tree species,shrub cover, Eagle'shabitat requirementsby describingthe habitatsit shrub height, dominant shrub species,understory cover, usesfor roostingand nestingin the southern limits of its understoryheight, and dominant herbaceousplants. range. RESULTS AND DISCUSSION MATERIALS AND METHODS Our studywas conductedduring 1996-97 in an area Three new records for the Crowned Eagle were re- coveringapproximately 5000 km" centeredin Lihue Cal- ported by staff of the National Park of Lihue Calel in el National Park (37ø54'S,65ø39'W), province of La Pam- 1996-97. On 18 November 1996, an eaglewas observed pa, Argentina. The area is situated at the ecotone be- perched in a tree approximately20 km eastof the Lihue tween savanna dominated by Prosopiscaldenia and Calel National Park. A secondsighting was made on 22 shrubland dominated by Larreaspp. Since the 19th cen- tury, the natural landscapehas been graduallymodified November 1996 approximately 40 km southeastof the by afforestationfollowed by extensiveranching. Current- park. The third sightingwas of a subadultCrowned Eagle ly, natural woodlandsoccur primarily in depressionsand on 21 September1997 perched in a Prosopistree in the ravines, and shrublands with isolated P. caldenia or small park. woodlotscharacterize the landscape.Fire is a common No Crowned Eagles were recorded during road sur- natural disturbanceand it is often prescribedto improve veys.Of the 20 farmers interviewed, 10 saidthey had seen grassproductivity. The clime is semiarid;mean temper- ature of the warmest and coolest months is 25øC and 9øC, CrownedEagles and their descriptionsfit the eagle'sfea- respectively,and the mean annual precipitation is 414 tures. All of the farmers referred to the large size and mm. head feathers, and most of them recalled the eagle's

312 DECEMBER 1998 SHORT COMMUNICATIONS 313 characteristic whistle and reluctance to fly off when ap- habitatsthat provide for tree, shrub and grasscover. The proached. Eagleswere encounteredwhile farmers were southern limit of the species'range appears to be at the walking(40%), driving (30%) or riding horses(30%). ecotonebetween the phytogeographicprovinces of Esp•n- Mosteagles were observedin naturalwoodlands (50%) al and delMonte, that occurthrough the NE-SW gradient or near tajamares(40%, artificialponds surrounded by of decreasingmean annual precipitation in Argentina. trees that provide water for cattle). Eagles were seen The Espinalis a savannadominated by Prosopissp. and del perched (80%), flying (10%) or perched and eating. Monteis characterizedby shrublandsdominated by Larrea Four encounterswere not consideredin the analysis,one sp. with isolated Prosopisand isolatedwoodlots occurring of them becauseit had occurred about six yearsprior to mainly in depressionsand ravines. the interview (all other sightingswere in 1996-97). The Crowned Eagles seem to depend on the presence of remaining three caseswere not used becausefarmers trees becausethey do not occur south in the Patagonian were unable to determine the exact location where .they steppe. In the southern limit of its range, the Crowned saweagles. No farmer recalled the encounter date and Eagle occursin a fairly transformedlandscape character- no dead eagleswere reported. ized by shrublandswith isolatedgroups of native trees Vegetationin all roosting habitatsconsisted of three providing nestingand roostinghabitats. This finding has strata.The dominant tree specieswas P. caldenia.Canopy conservation implications for Crowned Eagles. Current coverwas 37 --- 18% (i ñ I SD) and canopyheight was land management in the area includes afforestationfol- 6.2 --- 2.6 m. Dominant shrub specieswere Larrea nitida lowed by ranching. Creation of extensive areas lacking (presentin 67% of the describedsites), Lycium chilense treesor havingisolated trees may result in the reduction (17%) and Prosopisflexuosa.Other shrubspecies included of the eagle'srange. Conservationefforts should include Larreadivaricata (in 67% of the sites),Condalia microphylla the provisionof native woodlotsdue to their importance (67%), Chuquiragaerinacea (50%), followedby Geoffroea for Crowned Eagles. decorticans,Schinus fasdculatus, Prosopidastrumglobosum and Lydumgilliessianum. Shrub cover and heightwere 17 RESUMEN.--En este estudio aportamos nueva informa- ñ 16% and 1.6 ___0.2 m, respectively.The understorywas ci6n acerca de los requerimientosde h/tbitat del /tguila dominated by grasses( Stipagynerioides and S. tenuissima) coronada (Harpyhaliaetuscoronatus), a trav6s de la des- •n five of the describedsites, and by Verbenaaspera in the cripci6n de los sitiosusados como posadero en el limite remaining site. Siteswhere CrownedEagles were seen sur del Sea de distribuci6n de la especie. Adicional- roostingor nesting appeared to be similar to the typical mente, aportamostres nuevosregistros y describimosun tajamaror woodlotsin the area, but different from the nido. Los sitiosdonde las/tguilasfueron vistaseran sim- matrix of the shrubland landscape. ilares a un tipico tajamar (laguna artificial redeada de One nest site was found as a result of our interviews. firboles) o a un monte, pero diferentes a la matriz del The nest had been partiallydestroyed in the summerof paisaje de tipo arbustiva.La vegetaci6n presentabatres 1996 and it did not showany sign of activityon our visit estratos,donde Prosopiscaldenia (cald&n) era la espec•e in February 1997. It was located approximately12 km arb6rea dominante. La cobertura de la canopia era de east of the National Park in a natural 2 X 4 km forest of 37 ñ 18% (promedioñ 1 DE) y la altura de 6.2 +_2.6 P. caldeniacrossed by a stream. Habitat surrounding the m. Las especiesarbustivas dominantes eran Larrea nitida, nest tree had 45% canopycover and a canopyheight of Lydum chilensey Prosopisflexuosa. La cobertura y altura de 7 m. The middle stratum wasdominated by seedlingsof arbustosera de 17 ___16% and 1.6 -+-0.2 m, respectiva- P. caldeniaand by shrub speciessuch as L. chilense,P. flex- mente. E1 estrato bajo estaba dominado por pastos.La uosa, G. decorticans,S. fasdculatus,and C. microphylla. creaci6n de fireas extensas sin /trboles o con firboles ais- Mean shrub coverwas 25% and mean height was 1.5 m. lados podria resultar en la reducci6n del /trea de distri- The understorywas dominated by Stipagynerioides, S. ten- buci6n de la especie.Esfuerzos de conservaci6nrequer- uissima, and Bacchari ulicina. Percent cover of herbaceous ir/tn de un manejo del h/tbitat que provea grupos de plantswas 25% and height was0.4 m. The nest wasa firboles nativos. large platform of sticksplaced 6 m high in a 12 m Prosopis [Traducci6n de Autores] tree. It wassupported by two branchesand wasbuilt with ACKNOWLEDGMENTS Prosopisbranches that measured0.6-2.2 cm in diameter. Previously,Giai (1952) described two Crowned Eagle We deeply thank the logisticsupport provided by Ad- nestsbuilt on communal nestsof Monk Parakeets(Myiop- ministraci6nParques Nacionales of Argentina through A. sitta monachus)and De la Pefia (1992) described a large Balabusic, R. Milne, and M. Romero. Local farmers took platform nest 5 m up in an Eucalyptustree. Our results the time to guide us to the roosting spots, and kindly encouraged us to conduct research on their properties. showthat Crowned Eaglesmay build nestsin shorterand Suggestionsmade by G.R. Bortolotti and J.A. Don/tzar less conspicuoustrees than those dominating northern improved the manuscript.The work was funded by the savannas. American Bird Conservancy,the Universidad de Buenos Our sightingswere consistentin that CrownedEagles Aires, and the ConsejoNacional de InvestigacionesCien- were observedusing primarily P. caldeniafor roostingand tificasy T6cnicasof Argentina. 314 SHORT COMMUNIGATIONS VOL. 32, NO. 4

LITERATURE CITED FULLER,M.R. •4DJ.A. MOSHER.1987. Raptor survey tech- niques. Pages37-65 in B.A. Giron Pendleton,B.A. CHEBEZ,J.C. 1994. Los que sevan. Especiesargentinas en Millsap, K.W. Gline and D.M. Bird [EDS.], Raptor peligro. Editorial Albatros. management techniques manual. Natl. Wildl. Fed., COLL•, NJ, L.P. GONZ•G^,N. KR•BE, A. M^DROf40,L.G. Washington,DG U.S.A. N•UJO, T.A. P•qI•R )•ND D.C. WEGE. 1992. Threat- GI2a, A. 1952. Diccionario ilustrado de las aves argenti- ened birds of the Americas. The ICBP/IUCN red data nas. 1. Aves Gontinentales. Revista Mundo Agrario, book. SmithsonianInstitution Press,Washington, DC Editorial Haynes,Buenos Aires, Argentina. U.S.A. GIL, G., E. HAENEAND J.G. CHEBEZ.1995. Notas sobre la DE L• PEr4^,R.M. 1992. Las aves argentina. Editorial avifauna de Sierras de las Quijadas. NuestrasAves 31: L.O.L.A. 26-28. DE Lucc^, E.R. 1992. El/tguila coronada, Harpyhaliaetus S•'•LV2d)OR,S.A. AND P.G. EROLES. 1994. Notas sobre aves coronatus,en SanJuan. NuestrasAves 26:25. de Santiagodel Estero. NuestrasAves 30:24-25. 1993. Rapaces Amenazadas. E1 /tguila coronada. Nuestras Aves 29:14-17. Received30 January 1998; accepted 10 August 1998

J. RaptorRes. 32(4):314-318 ¸ 1998 The Raptor ResearchFoundation, Inc.

A COMPARISON OF METHODS TO EVALUATE THE DIET OF GOLDEN EAGLES IN CORSICA

JEAN-FRANGOISSEGUIN ParcNaturel Rggional de Corse,B.P. 417, F-20184 Ajaccio,Corsica and EcolePratique des Hautes Etudes, Laboratoire de Biogdographieet Ecologie des Vertdbrds, Place Eugdne Bataillon, F-34095 MontpellierCedex 05, France

PATRICK BAYLE 15 rue Bravet, F-13005 Marseille, France

JEXN-CL•UDETHIBAULT AND Jos•. TORR• ParcNaturel Rggional de Corse,B.P. 41 7, F-20184Ajaccio, Corsica

JEAN-DEN•SVIGNE CNRS, URA 1415, MusdumNational d'HistoireNatureRe, Laboratoire d •tnatomieComparde, 55 rue Buffon,F-75005 Paris, France

KEYWORDS' GoldenEagle;, Aquila chrysaetos;diet;, Corsica. diet. Previousstudies of the diet of Golden Eagles(Aquila chrysaetos)in the Mediterranean area have been basedon Identification of prey remains, pellet analysisand di- the collection of prey remains, without taking into ac- rect observationof prey deliveriesare the principal meth- count any possiblebiases in the data collectedusing only this technique (Handrinos 1987, Cheylan 1983, Fasce ods used to study the diets of nesting raptors (Marti and Fasce 1984, Fernandez 1991, Grubac 1987, Huboux 1987). Although it is often best to observeor film nests 1984). Considering that the variety of food resourceson for long periods to quantify prey deliveries,this is not Mediterranean islands is limited (Seguin and Thibault alwayspossible due to time and logisticalconstraints. To 1996) with a moderate spectrum of potential prey, we assessthe validity of using prey remainsand pellets as a conducted this study to determine the best methods for means of determining diet, several authors have com- monitoring the diet of Golden Eagles on Corsica. pared data from collectionsof nest contentswith data obtained from direct observationfor variousraptor spe- STUDY AREA AND METHODS cies (Collopy 1983, Simmonset al. 1991, Mersmann et Corsica(42øN, 9øE) is one of the major islandsin the al 1992, Mafiosa 1994, Real 1996). Overall, they have westernMediterranean covering an area of 8750 km2. It found that by combining remains and pellets, collected supportsa breedingpopulation of 32-37 pairsof Golden with the same level of effort, it is possibleto determine Eagles (Torre 1995). Our study area, in the Verghello