j. RaptorRes. 36(4):315-319 ¸ 2002 The Raptor ResearchFoundation, Inc.

PREYOF THE PEREGRINEFALCON (FALCOPEREGRINUS CAS57Ni) IN SOUTHERN ARGENTINA AND

DAVID H. ELLIS 1 USGSPatuxent WildliJb Research Cente•; HC 1 Box 4420, Oracle,AZ 85623 U.S.A.

BETH ANN WildlifeForensics Services, P.O. Box 142613, Irving, TX 75014-2613 U.S.A.

J^MESK. F^CK•ER 590 Davidson Road, Bow, WA 98232 U.S.A.

BRL•N A. M•LLS^P Fish and WildlifeConservation Commission, 620 S. Me•dian Street,Tallahassee, FL 32399 U.S.A.

K•YWoRD$: PeregrineFalcon; Falco peregrinus;Argentina; tached) but discarded those bones that were so bleached Chile;,Pallid Falcon; prey. that they may be attributed to former occupantsof the eyrie. Most of the prey were identified from whole feath- ers. No pellets were used in this anaylsis.We included The (Falcoperegrinus cassini) in Pata- some feathers f?om the base of the eyrie cliffg, but ex- gonia attracted wide interest two decadesago (Anderson cluded those that were likely molted by other occupants and Ellis 1981, McNutt 1984) when there was a focus on of the cliff. For example, severalof our eyrieswere in old determining the taxonomic position of the Pallid Falcon Black-faced (lbrmerly buff-necked) (Theristicuscau- (also called Kleinschmidt'sfalcon and Tierra del Fuego datus) nests within active ibis colonies. Although •b•s falcon; formerly named Falcokreyenborgi). In 1981, how- feathers were frequently found near these eyries and ever, the pallid falcon was confirmed to be a pale color even though we occasionallyobserved peregrines pursu- morph of the peregrine (Ellis et al. 1981, Ellis and Peres ing ibis, we viewed these attacksnear eyries as displace- 1983), and since that time, little work has been conduct- ment activities.Only once did we include an ibis as prey and this was after finding four fresh •athers within an ed on this color morph. Continent-wide research has eyrie which was neither beneath an ibis roost nor near continued and has yielded a fair understanding of the an ibis nest. McNutt (1981) observed peregrines kilhng breeding distribution of the Peregrine Falcon in South nestling ibis. America (Anderson et al. 1988, McNutt et al. 1988, Rise- No food habits studybased on prey remains is without brough et al. 1990). Also, two preliminary food habits bias (Marti 1987, Bielefeldt et al. 1992). For peregrines, studies on the peregrine have been completed in Pata- bias derivesfrom the fact that many prey individualsare gonia (McNutt 1981, Peres and Peres 1985). Together missedbecause prey are normally plucked belbre arrival those papers provided a list of 23 speciesobserved as at the eyrie and many defieshed carcassesare removed prey, and McNutt (1981) listed another eight species by the adults and deposited elsewhere.Also, severalcast- seen pursued (but not captured) by peregrines. ings sometimesrepresent a single prey item. Common prey are normally under represented in peregrine prey The purpose of this paper is to assembleall that has tallies, including our sample,because of the difficulty of been published on peregrine food habits for totaling individuals. Our method was to derive a mira- and Tierra del Fuego and to add to that list from our mum count from feet, bills, remiges, and rectrices. For 1980 and 1981 expeditions. example, a sample of 300 feathers and assorted other remains from one species, and probably representing METItODS dozens of individuals, may yield a much smaller mm•- In November-December of 1980 and 1981, we traveled mum count. Conversely,rare prey are likely to be over by motor vehicle searching for eyries in Chubut, Santa estimated in most studiesincluding this one, because a Cruz, and Rio Negro provincesof Argentina and in Ma- single feather, bill, or foot can document prey that was gallanes, Chile. Although we accessed16 eyries, some accrued only once. were empty (prey remains sometimes scatter in the Prey were placed in plasticbags and air dried by open- wind), so our totals included prey from only 11 eyries. ing the bags in a windless situation on sunlit days and We accessedeyries (normally by rope) and recovered re- fumigated prior to identification at the U.S. National Mu- cent prey (feathers, feet, and bones with tendons at- seum (USNM: Smithsonian Institute). At USNM, we as- sembled a synopticseries including all known and most of the likely prey species.Because USNM does not have E-mail address: [email protected] dcellis@ examples for all plumages of all Patagonian birds, we theriver. corn could not determine specieson nine individuals.

315 316 SHORT COMMUNICATIONS VOL. 36, NO. 4

Table 1. Avian prey of the Peregrine Falcon in southern Patagoniaand Tierra del Fuego) ,2 Numbers refer to minimum number of items representedin remains. A plus (+) indicatesthat a taxa wasdocumented, but the number of items was not reported. Nomenclature follows Sibley and Monroe (1990).

PERES AND MCNUTT PERES THIS FAMILY SCIENTIFIC NAME COMMON NAME 1981 s 19853 STUDY 3

Rheidae Rheapennata Lesser Tlnamidae Eudromiaelegans Elegant Crested- Podicipedidae Podicepsmajor Great Halobaena caerulea Blue Pachyptilabelcheri Slender-billed Prion Pelecanoididae Pelecanoidesmagellani Magellanic Diving-Petrel Pelecanoidessp. 3 Ardeidae Nycticoraxnycticorax Black-crownedNight- 1 Theristicus caudatus Buff-necked Ibis 7 *4 1 CMoephagapicta Upland 1' A nas sp. 1 Anasflavirostris Speckled Teal 2 1 Anasplatalea Red Shoveler Falcosparverius 2 Gallusgallus domesticus Domestic Chicken 1' Rallidae Fulica leucoptera White-winged 1 Vanelluschilensis Southern 1 + 3&2' Charadriusfalklandicus Two-banded + Charadrius modestus Rufous-chested Plover + Oreopholusruficollis Tawny-throatedDotterel 1 + 7&1' Scolopacidae Limosahaemastica Hudsonian + Gallinagostricklandii 1 Thlnocoridae Thinocorusorbignyianus Gray-breastedSeedsnipe 2 + 4 Thinocorusrumicovorus Least 17 + 5 Larldae Sternasp. 2 Sterna hirundinacea + Zenaida auriculata Eared Dove 16 Metriopeliamelanoptera Black-wingedGround-dove 1 Columba livia + Pslttacidae Cyanoliseuspatagonus BurrowingParakcet 2 Enicognathusferrugineus Austral Parakeet 4 1 Caprimulgidae Caprimulguslongirostris Band-wingedNightjar 1 Furnariidae Geositta cunicularia Common Miner 3 Upucerthiadumetaria Scale-throatedEarthcreeper 2 Eremobiusphoenicurus Band-tailed Earthcreeper 2 Cinclodesfitscus Bar-wingedCin clodes 1 Cinclodespatagonicus Dark-bellied Cinclodes 4 Leptasthenuraaegithaloides Plain-mantled Tit-Spinetail 1 Tyrannidac Neoxolmisrufiventris Chocolate-ventedTyrant 1 + 2 Muscisaxicolamacloviana Dark-faced Ground-Tyrant 1 Lessoniatufa Patagonian Negrito 1 Hirundinidae 7achycinetameyeni Chilean 2 Notiochelidoncyanoleuca Blue-and-white Swallow 2 Troglodytidae Troglodytesmusculus Tropical House- + Sturnidae Mimuspatagonicus PatagonianMockingbird 1 Muscicapidac Turdusfalcklandii Austral Thrush 2 + 2 DECEMBER 2002 SHORT COMMUNICATIONS 317

Table 1. Continued.

PERES AND MCNUTT PERES THIS FAMILY SCIENTIFIC NAME COMMON NAME 1981 s 1985 s STUDY 3

Montacillidae Anthuscorrendera Correndera Pipit 1 Fringillidae Agelaiusthilius Yellow-wingedBlackbird 1 Sturnellamilitaris Pampas Meadowlark + Sturnellaloyca Long-tailed Meadowlark 1 Molothrusbonariensis 1 Phyrgilusgayi Grey-hooded Sierra- 1 Phyrgilusfruticeti Mourning Sierra-Finch 3 Phrygilusunicolor PlumbeousSierra-Finch 1 Melanoderamelanodera Canary-wingedFinch 1 Diuca diuca Common Diuca-Finch 3 Sicalis luteola Grassland Yellow-Finch 3 Carduelis barbata Black-chinned Siskin 1 Unknown 8 0 9

Total individuals 53+ unknown 102 Total identified individuals 45 unknown 93 Minimum no. species 13 17 42 Not listedis a Kelp (Larus dominicanus)observed as prey of a juvenile Pallid Falcon on 10 March 1979 (Ellis and Glinski 1980) Nonavianprey include only a lizard (Liolaemussp.) m•d a smallrodent. An asterisk(*) in thesecolumns identifies prey that had not achievedadult size. it is not certain that all 7 ibis were nestlingswhen taken.

We identified feathers by placing materialsfrom one RESULTS eyrie in a shallow white box and from prior experience sorted the feathers into piles tentativelyassigned to a like- From this and the previoustwo studies(McNutt 1981, ly taxon. A representativefeather wasgrasped by forceps Peres and Peres 1985), we have documented a fair variety then compared to specimensof likely donor species. of the prey taken by the peregrine in Patagonia.McNutt Once a good match for size, color, and pattern was (1981) identified 13 prey speciesand two other genera. found, the pile of featherswas sorted to remove any that Peres and Peres (1985) noted 17 species,of which 10 did not representthis speciesand morph. Then the pro- were new (i.e., not previouslynoted by McNutt [1981]) cesswas commenced anew. After one of us completedan The list from our study (Table 1) includes42 speciesof •dentificationfor featherswithout unique color patterns which 32 were not previouslyrecorded. In summary, at (and most passefine primaries do not have bold color patterns), a second person evaluated the feathers and least 55 prey speciesin 26 families are known to be taken confirmed or rejected the identification. The most diffi- by peregrines in Patagonia. To this can be added the cult materials often required an evaluation extending an (Larus dominicanus)recorded as prey of a ju- hour or more before a certain match was found. Occa- venile Pallid Falcon seen on 10 March 1979 (Ellis and stunally,a feather had to be washed and blow dried be- Glinski 1980). fore comparisonscould be made. All identified materials were baggedseparately and archived. DISCUSSION In comparing feathers, it was often necessaryto fan the wing or tail on the museum skin; to do so without Our list doesnot representthe full range of prey taken tearing the skin required holding the appendage in by the Peregrine Falcon in South America, becausefirst alignment with the body while deflecting the tip of the of all, our study included only the southern fifth of the feather with forceps.To aid in this process,we prepared distribution of this race. Second, other prey speciesare flat skinswith tail and one wing fanned for about 50 spe- known to be taken by this falcon in the Falkland Islands cieswhile in Argentina. For some other species,we mere- (Cawkell and Hamilton 1961) and in more northerly re- ly placedwings, tail, feet, beak, and feathersrepresenting gions of South America (Hilgert 1988). Third, the low all body areasin a plasticbag. All specimenswere deliv- ered to the Argentine Museum of Natural Sciences, numbers of individualstaken for common and likely prey BuenosAires, Argentina, where the most valuablewere species(e.g., only two Austral Thrushes [ Turdusfalcklan- retained. The remainder were released for export and dii] and one Patagonian [Mimus patagon•- shipped to the U.S.A. cus]) suggestthat much more varietywill come from con- 318 SHORT COMMUNICATIONS VOL. 36, NO. 4 unued sampling.The relationship between diversity(i.e., sugiere que la diversidadde avestomadas fue mucho mas the number of speciesdetected) and samplesize can be grande que la que se describeaquL Estaalta diversidad, characterized as beginning with a 1:1 relationship but en parte, resulta de variedadespalidas y de color normal w•th the plot soon leveling off and finally approaching que ocupan nichos de forrajeo un tanto ditbrentes. an upper asymptote (the true maximum in the number [Traducci6nde C6sarMarquez] of speciestaken) only after severalhundred prey are tal- hed (Heck et al. 1975, Marti 1987). At present,the total ACKNOWLEDGMENTS for all three studies is less than 200 individuals. Further, In 1980, the U.S. Air Force funded much of our travel the two most commonly taken speciesin Table I were Our 1981 work was largely funded by the National Geo- representedby only ca. 23 and 16 individuals;betbEe the graphic Society and an anonymousphilanthropist. We upper asymptoteis reached, we expect that the number thank Peter Simpson, manager of EstanciaChacabuco, Rio Negro, Argentina, for logisticalsupport. Phil Angle of individualsof the most commonly-takenprey will ex- ceed 100. identified the lizard. Jamie Jimenez, ClaytonWhite, and David Whiracre reviewedand improvedthe manuscript The list of speciestaken (Table 1) suggeststhat the Our thanks to staff at the USNM for allowing spacefor peregrine is prone to capture some prey on the ground. our synoptic series and patience during the extended The gosling was observedbeing taken on a gravel bar. time devotedto identifyingprey. Surely,the young rheas,perhaps the tinamou, and likely some of the other young birds in Table 1 were taken on LITERATURE CITED the ground. In addition to the avian prey tallied, we also ANDERSON,C.M. ANDD.H. ELLIS.1981. FalcokreyenborgJ-- recorded one lizard (Liolaemussp.) and a sinall mammal a current review. RaptorRes. 15:33-41. (Rodentia ca. 40 g); both of thesewould likely havebeen , t.L. M_AECHTLE, AND W.G. VASINA. 1988. The taken on the ground (or kleptoparasitized).In South southern breeding limit of the PeregrineFalcon. Pag- America there is no competing large falcon that hunts es 251-253 in T.J. Cade, J.H. Enderson, C.G. Thelan- terrestrial prey (i.e., like the Prairie Falcon [F. mexicanus] der, and C.M. White lEDS.], Peregrine Falcon popu- in North America and the Saker Falcon [F. chefrug]in lations: their management and recovery. The Europe and Asia) that may constrain the Peregrine Fal- Peregrine Fund, Boise, ID U.S.A. con to an aerial foraging niche, so it was to be expected BIELEFELDT,J., R.N. ROSENFIELD,AND J.M. PAPP.1992. Un- that the peregrine in Patagoniawould take quarry on the ibunded assumptions about diet of the Cooper's ground more frequently than do some other races. . Condor 94:427-436. It is obviousfrom the variety of oceanic specieson the C^WKE[L,E.M. ANDJ.E. HAMraTON.1961. The birds of Pereslist (Peresand Peres 1985; Table 1) that their study the Falkland Islands. Ibis 103:1-27. emphasizedcoastal areas. Their sample was also ikom an ELLIS, D.H. AND R.L. GLINS•a. 1980. Some unusual re- area where the pallid morph is relatively common (G. cords for the Peregrine and Pallid Falcons in South Peres pets. comm.). Their results, in comparison with America. Condor 82:350-351. our list for inland eyries,where the pallid morph is rare, --AND C. PERES.1983. The Pallid Falcon Falco krey- suggestthat pallid and dark peregrines hunt different enborgiis a color phaseof the AustralPeregrine Falcon prey. To document this potential difference (i.e., to com- (Falcoperegrinus cassini). Auk 100:269-271. pare the foraging niches of two sympatriccolor morphs) , C.M. ANDERSON, ^ND TB. ROUNDY. 1981. Falco will surely be an interesting ecological study.Pallid and kreyenborgi:more piecesfor the puzzle. RaptorRes. 15. normal birds appear very different in the field. Pallid 42-45. birds are less conspicuousand gull-like when seen be- HECK,K.L., JR., G. VANBELt•;, AND D. S•M}•ERLOFF.1975 neath gray, overcastskies. We propose that the pallid Explicit calculation of the rarefaction diversity mea- morph may have evolvedwhen conditions were right for surement and the determination of sufficient sample a population of pale peregrinesto live in isolationfrom size. Ecology56:1459-1461. the population of normal peregrines further north on HILGERT,N. 1988. Aspectsof breeding and feeding be- mainland South America. havior of Peregrine Falcons in Guayllabamba,Ecua- dor. Pages749-755 in T:I. Cadc,J.H. Enderson,C.G RESUMEN.--ApartiE de publicacionesprevias, conocelllos Thelander, and C.M. White [Er•s.], Peregrine Falcon menos de 100 item presa que representan poco menos populations: their management and recovery. The de 25 especiesde avespara el halc6n peregrino de la Peregrine Fund, Boise, ID U.S.A. Patagonia (Falcoperegrinus cassini). Este estudio, incluye 1VL•mTI,C.D. 1987. Raptor food habitsstudies. Pages 67- presasde 11 nidos, ariade 93 presasidentificadas repre- 80 in B.A.Giron Pendleton,B.A. Millsap, K.W. Cline, sentando 42 especiesde aves (32 no reportadas previa- and D.M. Bird [EDs.], Raptor management tech- mente), un lagatto, y un mamifero pequefio.Aunque do- niques manual. Natl. Wildl. Fed. Sci. Tech. Ser. No cumentamosuna considerablevariedad de presaspara el 10. halc6n peregrino en estaregi6n, la frecuencia con la cual MCNUTT,J.W. 1981. Selecci6nde presay comportamien- nuevas presas fueron encontradas en cada nido visitado, to de caza del Halc6n Peregrino (Falcoperegrinus) en DECEMBER 2002 SHORT COMMUNICATIONS 319

Magallanesy Tierra del Fuego. An. InstßPatagonia 12: RISEBROUGH, R.W., A.M. SPRINGER, S.A. TEMPLE, C.M. 221-228. WHITE, J.L.B. ALBUQUERQUE,P.H. BLOOM,R.W. FYFE, ß 1984. A Peregrine Falcon polymorph: observa- M.N. I•RWN, B.A. LUSCOMBE, D.G. ROSENE^U, M. tions of the reproductivebehavior ofFalco kreyenborgi. SANDER,NJ. SCHMITT,C.G. THELANDER,W.G. VASINA, Condor 86:378-382. AND W. WALKER, II. 1990. Observaciones del halcon , D.H. ELLIS, C. PERES,T.B. ROUNDY, W.G. VASINA, peregrino, Falcoperegrinus subspecies, en America del AND C.M. WHITE. 1988. Distribution and status of the Sur. Rev. Bras. Biol. 50:563-574. PeregrineFalcon in SouthAmerica. Pages 237-249 in T.J. Cade, J.H. Enderson,C.G. Thelander, and C.M. SIBLEY,C.G. ANDB.L. MONROE,JR. 1990. Distribution and White [EDS.], Peregrine Falcon populations: their taxonomyof birds of the world. Yale Univ. Press,New management and recovery.Peregrine Fund, Boise, Haven, CT U.S.A. ID U.S.A. PERES,M. ANDC. PERES.1985. Peregrine project, Argen- tina (activities 1982). Bull. WWGBP2:109-110. Received7 January 2001; accepted 10 July 2002