SEPTEMBER 2000 SHORT COMMUNICATIONS 237

ACKNOWLEDGMENTS P.D. OLSEN,J.L. PETERSEN,J.L. RANGELSALAZAR, K P We thank R. C•tceres, M. Favero, S. and L. Bachmann, SEGARS,AND K.L. WOOD. 1999. Family Strigidae (Typ- and students for field assistance, and A. Malizia for as- ical Owls). Pages152-242 inJ. del Hoyo, A. Elliot, and sistingin mammal identification. E Jaksicand two anon- J. Sargatal [EDS.],Handbook of the of the world. ymousreferees made important contributionsto improve Vol. 5. Barn Owls to hummingbirds. Lynx Edicions, this paper. Finally,we would like to expressour especial Barcelona, Spain. gratitude to Mariano Manuel Martinez, and this paper is JIMI•NEZ,J.E. 1993. Notes on the diet of the Aplomado dedicated to his memory. Falcon (Falcofemoralis)in northcentralChile. J. Raptor Res. 27:161-163. LITERATURE CITED MARTINEZ,M.M., J.P. ISACCHAND F. DONATTI. 1996. As- BLEDINGER,P., E. DE LUCA, AND M. SAGGESE.1987. Nidi- pectos de la distribuci6n y biologia reproductiva de Asio clamatoren la Provincia de Buenos Aires, Argen- ficaci6n otofio-invernal del Lechuz6n Orejudo. Nues- tras Aves 5:19. tina. OrnitologiaNeotropical 7:157-161. NAROSKY, W. AND A. DI GIACOMO. 1993. Las aves de la BURTON,J. [ED.]. 1973. Owls of the world. Their evolu- provincia de Buenos Aires: distribuci6n y estatus. tion, structure and ecology.E.P. Dutton and Co., Inc., New York, NY U.S.A. Asoc. Ornitol6gica del Plata, Vfizquez Mazzini Ed y L.O.L.A., BuenosAires, . CABRERA,A. 1976. RegionesFitogeogr•tficas . PHELPS,JR., W.H. AND R. MEYERDE SCHAUENSEE.1994. Enciclopedia Argentina de Agricultura y Jardinerla. Una guia de las avesde Venezuela. Gr•ficas Armitano, Tomo II, fasciculo1. Ed. Acme, BuenosAires, Argen- Caracas, Venezuela. tina. CAMPERI, A.R. 1992. Estudio sobre aves colectadas en el R•DFORD,K.H. ANDJ.E EISENBERG.1992. Mammals of the extremo sudoeste de la Provincia de Buenos Aires. neotropics.The Southern Cone. Vol. 2. Univ. Chicago Neotropica38:127-140. Press,Chicago, IL U.S.A. CANEVARI,M., P. CANEVARI,G.R. CARRIZO,G. HARRIS,J. SALVADOR,S.A. 1988. Datos de peso de aves argentinas. Hornero 13:78-83. RODRIGUEZMATA, AND R. STRANECK.1991. Nueva guia de las avesargentinas. Tomos I y II. Fundaci6n Acin- VERVOORST,E 1967. Las comunidadesvegetales de la de- dar, Buenos Aires, Argentina. presi6n del Salado (Prov. de BuenosAires). INTA. La GROSSMAN,M.L. ANDJ. HAMLET.1964. Birds of prey of vegetaciSndela Rept•blicaArgentina 7:1-262. the world. Bonanza Books, New York, NY U.S.A. HOLT, D.W., R. BERKLEY,C. DEPPE,P.L. ENRIQUEZROCHA, Received 1 May 1999; accepted 20 March 2000

j. RaptorRes. 34(3) :237-241 ¸ 2000 The Raptor ResearchFoundation, Inc.

DIET OF BREEDINGCINEREOUS HARRIERS (CIRCUS CINEREUS) IN SOUTHEASTERN BUENOSAIRES PROVINCE,ARGENTINA

MAR/A S. B(5, SANDRAM. CICCHINO, AND MARIANOM. MARTINEZ1 Departamentode Biologia,Facultad de CienciasExactas y Naturales,Universidad Nacional de Mar delPlata, Funes 3350, (7600) Mar delPlata, Argentina

KEy WORDS: CinereousHarrier;, Circus cinereus;breeding common in Patagoniaand Islas Malvinas (Narosky and diet;,trophic niche breadth; Argentina. Yzurieta1987) but it has alsobeen recordedthroughout northwestern, central and, occasionally,the northeastern The Cinereous (Circus cinereus), one of two parts of the country (Canevari et al. 1991). The Cinere- South American harriers, is widespread and distributed ous Harrier inhabits savannas, grasslands, wetlands, from and Ecuador, through Peril, and marshes,lagoons, shrubsteppes,and shrublands 0-4500 ,southwestern to Tierra del Fuego and m elevation (Jim•nez and Jaksic 1988, Canevari et al. Islas Malvinas (Grossman and Hamlet 1964, Canevari et 1991, Narosky and Di Giacomo 1993, del Hoyo et al. al. 1991, del Hoyo et al. 1994). In Argentina, it is most 1994). Little has been reported about the CinereousHarrier The few previous studiesof this specieshave focused on i Deceased. aspectsof ecology and behavior (Jim6nez and Jaksic 238 SHORT COMMUNICATIONS VOL. 34, NO. 3

1988) and breedingbiology (Narosky and Yzurieta1973, were calculated as i -+ SE (Marti 1987). Levins' index of Saggeseand De Lucca 1995). General information about trophic niche breadth (Marti 1987) wascalculated as fol- its feeding habits suggeststhat it eats birds, small mam- lows:B: 1/•n=1p2•, where pi is the proportionof prey mals, and reptiles (Humphrey et al. 1970, De La Pefia in different categories(mainly species).B variesfrom 1 to n, maximum number of prey categories.If prey are 1985, Canevariet al. 1991, del Hoyo et al. 1994). Its diet equallycommon in all categories,then B = n. If all prey has only been analyzedin detail in southernmostChile belong to only one category,B = 1. (Jim•nez and Jaksic 1988), where it preys on insects, birds, mammals, reptiles, and arachnids. In this paper, RESULTS we report on the breeding seasondiet and trophic niche breadth of the Cinereous Harrier in the PampasZone of We collected 63 pellets and 45 prey remains from five Argentina. Cinereous Harrier pairs breeding in 1992-93 and five pairs breeding in 1993-94. The pellets had a mean METHODS length of 35.9 + 8.0 mm (+SD) and a mean width of The studywas carried out in Lagunade los PadresIn- 17.7 + 2.9 mm (N = 53). A total of 104 prey items was tegral Reserve(37ø56'S, 57ø44'W), located 16 km westof identified from three taxonomic classes that included 20 Mar del Plata City, in southeasternBuenos Aires Prov- vertebrate speciesand unidentified items (Table 1). Lev- ince. The reserve is 680 ha in size, with a gentle relief ins' index was 7.1 (N = 20). Birds accounted for 94% of composed of low hills and plains. The climate is subhu- the total prey items,followed by mammals(5%). Only mid to humid with a mean annualtemperature of 13.8øC and a mean annual precipitation of about 844 mm (J. one amphibian was identified (Table 1). Cionchi unpubl. data). Avian prey included 14 species,with passerinesbeing The breeding area studiedwas located in the "El Cur- the most commonof all prey (88%) (Table 1). Among ral" Intangible Reserve Zone, an area 87 ha in size, passerines,House Sparrows(Passer domesticus) (21%), Ru- where CinereousHarriers nestedin sympatrywith Long- fous-collaredSparrows (Zonotrichia capensis) (19%), and winged Harriers (Circusbuffoni). The area is character- GrasslandYellow-finches (Sicalis luteola) (19%) were the ized by a mosaic of shrublandsconsisting of the native most abundant species in the diet. Doves (15%), the "Curro" (Colletiaparadoxa), the exotic blackberry (Rubus Eared Dove (Zenaida auriculata), and the Picui Ground- ulmifolius)and modified pampean grasslandgenera such as Stipa,Bothriochloa, Conium, and Carduus(Cabrera and Dove (Columbinapicui), were the secondmost numerous Zardini 1978). Cultivatedfields, pastures, tree plantations taxa consumed(Table 1). Among mammal prey,rodents (mainly Eucalyptusspp.), and suburbanzones surround were the most common (3%), followed by lagomorphs the core study area, which is located 400 m from the (2%) (Table 1). Prey weights of consumed closestwater (Laguna de Los Padres). ranged from 1.5 g ( egg in one pellet) to 300 g (ju- Harrier pellets and prey remainswere collectedevery venile European hare, Lepuscapensis) (Table 1). The geo- 5-6 d from nesting sites,plucking stations,and roosts metric mean weight of prey was31.2 g _+5.5 (roSE). Most from September to March of 1992-93 and 1993-94. Iden- ufication of remains of birds, mammals, and amphibians prey (84%) weighed<60 g, and the mostabundant prey found in pellets and other prey remains was based on were GrasslandYellow-finches, House Sparrows,and Ru- bones, feathers, beaks,hair, and dentition. We compared fous-collaredSparrows. these items to collections in Museo de Ciencias Naturales Birds contributed most to the total prey biomass de La Plata, Museo de CienciasNaturales "Lorenzo Scag- (81%), with Eared Doves(28.2%) being the main con- ha" de Mar del Plata along with the collectionsof the tributor. House Sparrows(14.3 %), Rufous-collaredSpar- Laboratorio de Vertebrados, Facultad de Ciencias Exactas rows (9.2%), and GrasslandYellow-finches (6.7%) were y Naturales-UniversidadNacional de Mar del Plata. Most also important in the biomass.Biomass contributed by prey items were identified to species.During identifica- tion, pellets and prey remainsin a day'scollection from mammalswas 15%, with juvenile Europeanhares con- each breeding pair were lumped and reconstructedby tributing the highestvalue (12.5%). Amphibianbiomass matching the remiges, rectrices, beaks, and bones of was low (3.8%) in the diet of this harrier (Table 1). birds and the fur, skull parts, and feet of mammals.This procedure minimized the possibilityof overcountingthe DISCUSSION number of individualsof each species(Marti 1987). Weights of adult birds were obtained from the litera- Birds were the most common prey in the diet of the ture (Fiora 1933, Contreras 1979, Salvadorand Salvador Cinereous Harrier, both numerically and in terms of bio- 1986, Salvador 1988, 1990, Camperi 1992) and from un- mass.Birds are the most common prey of many other publisheddata of the Museo de CienciasNaturales "Lor- speciesof Circus(Schipper 1973, Baker-Gabb1981, Bar- enzo Scaglia" (Mar del Plata City). Weights of mammals nard et al. 1987, Witkowski1989, Gonz/dezL6pez 1991, were provided by M. Kittlein (unpubl. data) and V. Com- del Hoyo et al. 1994, B6 et al. 1996). CinereousHarriers paratore and A. Barbini (unpubl. data). The weight of the common toad (Bufo arenarum)was taken from Lan- preyed primarily upon passerinebirds such as House gone (1994). When the sex of prey could not be deter- Sparrows,Rufous-collared Sparrows, and GrasslandYel- mined, the mean weight of males and females for that low-finches. specieswas used. Geometric mean weightsfor total prey The food habits we recorded differed from those re- SEPTEMBER 2000 SHORT COMMUNICATIONS 239

Table 1. Percent total frequency of prey items, mean individual weight, and percent total biomassin the diet of CinereousHarriers during the breeding seasonin southeasternBuenos Aires Province,Argentina.

% TOTAL MEAN INDMDUAL % TOTAL PREY FREQUENCY WEIGHT (g) BIOMASS Amphibia (1.0) a Bufonidae Bufoarenarum 1.0b 180 3.8 Birds (94.0) Nonpasserine Columbidae Columbinapicui 5.5 55 6.9 Zenaida auriculata 9.5 135 28.2 Picidae Colaprescampestris 1.0 200 4.2 Passerine Tyrannidae Tyrannusmelancholicus 1.0 45 0.9 Troglodytidae Troglodytesaedon 1.0 10 0.2 Emberizidae Sicalis luteola 19.0 16 6.7 Sicalisluteola (egg) 1.0 1.6 <0.1 Sicalisspp. 2.0 16 0.7 Zonotrichiacapensis 19.0 22 9.2 Sparophilacaerulescens 1.0 11 0.2 Molothrus bonariensis 2.0 62 2.6 Molothrus badius 2.0 53 2.2 Carduelismagellanica 3.0 15 0.9 Carduelis chloris 3.0 25 1.6 Ploceidae Passer domesticus 21.0 31 14.3 Unidentified Passeriformes 2.0 23 c 1.0 Unidentified birds 1.0 46 d 0.9

Mammals (5.0) Leporidae Lepuscapensis (juveniles) 2.0 300 12.5 Muridae Oxymycterusrufus 1.0 70 1.5 Akodon azarae 1.0 21 0.4 Unidentified murids 1.0 45 e 0.9

Total Number of Prey Items 104 Total by prey class. Total by prey species. Averageof the three most common passerinebirds in the sample. Averageof all the birds in the sample. Average of the two murids in the sample. ported previously.In southernmostChile, Jimfnez and nanfly upon rats and field mice (speciesnames not pro- Jaksic (1988) identified a total of 1259 prey items of vided by these authors), and that they also ate birds, which 33.6% were insects,followed by birds (27.2%), insects,and reptiles.In Tierra del Fuego, the Cinereous mammals (19.1%), reptiles (19.1%), and arachnids Harrier did not prey on birds, taking only lizards and (1.0%). House (in Jimfnez and Jaksic1988) alsoindicat- rodents(Humphrey et al. 1970). The absenceof reptiles ed that Cinereous Harriers in preyed predomi- in the diet of birds from our study area in part might 240 SHORT COMMUNICATIONS VOL. 34, No. 3 have been due to their lower availabilityin comparison 10 parejas nidificantes. Se identificaron 104 items presa, to Chile and Patagonia. corespondiendoel 94% alas aves,el 5% a los mamiferos In terms of biomass,birds were the most important y un solo anfibio. La amplitud de nicho trCfico (B) fue group in the diet, a finding that was similar to that of de 7.1 (N = 20). Los paseriformesfixeron las presasmrs JxmCnezandJaksic (1988) in southernmostChile. Three comunes (88%) del total de items presa, dentro de las species,Eared Dove, House Sparrow,and Rufous-collared cuales el GorriCn (Passerdomesticus), el Chingolo (Zono- Sparrow,made up over 52% of the biomassin our study. trichia capensis)y el Misto (Sicalisluteola) fueron las prin- When compared with the diet of Long-wingedHarrier cipales especies capturadas. La media geomCtrica del (B6 et al. 1996), which nests sympatricallywith the Ci- peso de presasconsunfidas fue de 31.2 g + 5.5 (• --- SE) nereous Harrier, we found that the values of trophic (rango = 1.5-300 g). En cuanto a la biomasa aportada niche breadth were similar for the Long-wingedHarrier las avescontribuyeron en un 81%. La dieta del Gavilfn (standarized Levins' index - B' = 0. 21) and the Cine- Ceniciento en la provincia de Buenos Aires difiri6 con reous Harrier (B' = 0.19; N = 34). There was both over- otras fireas de estudio (Chile y zona PatagCnica) pero lap and divergencein the prey of these sympatricspecies present6 sinfilitud con su congCnere el Gavilfn Planea- (Pianka's overlap index = 0.67; this value calculated dor (Circusbuffoni) nidificando en simpatria. from data of this study and data of B6 et al. 1996). For [TraducciCn de Autores] both species,birds were the most abundant prey.For the Cinereous Harrier, birds comprised 94.2% of the diet ACKNOWLEDGMENTS whereas for the Long-wingedHarrier, birds comprised We thank R. Simmonsfor his very helpful suggestions, 80%. Both harriers preyed principally upon passerines E. Madrid and R. Cfceres for their valuable help in the (Cinereous Harrier = 81.2%, Long-winged Harrier = field and A. Vassallo for assistance in mammal identifi- 61.2%), with Rufbus-collaredSparrows being most com- cation. We also thank N. B6 and C. Darrieu, curators of mon in both diets (Cinereous Harrier = 19%, Long- the Museo de Ciencias Naturales de La Plata, and S. Cas- ertano and D. Romero of the Museo de Ciencias Natur- winged Harrier = 27.5%). The Long-wingedHarrier ales "Lorenzo Scaglia,"who allowed accessto collections preyed upon aquatic birds (7.2%) which did not occur under their care.The continuedsupport of J. B6 is great- in the diet of the Cinereous Harrier. Mammals were the ly appreciated. We are grateful for the review and com- secondmost common taxa consumedby the two harriers, ments provided by D. Smith, D. Varland, and two anon- although the percentage varied (Cinereous Harrier = ymous reviewers.Finally we would like to expressour 5%, Long-winged Harrier = 17.5%). Utilization of ter- specialgratitude to Mariano Manuel Martinez. This pa- restrialprey wascomparable with observationsof Narosky per is dedicatedto his memory. and Yzurieta (1973) who found that Cinereous Harriers LITERATURE CITED were more terrestrial hunters than Long-winged Harri- ers. BAK•R-GABB,DJ. 1981. Breeding behaviour and ecology Minimum prey weight did not vary betweenCinereous of the AustralasianHarrier (Circusapproximans) in the Harriers (1.5 g: GrasslandYellow-finch egg) and Long- Manawatu-Rangitikei Sand-Country,New Zealand. N0- wangedHarriers (1 g: insects)but the maximum weight tornis 28:103-119. was greater in Long-winged Harriers than that in Cine- BARNARD, P.E., B. MACWHIRTER, R. SIMMONS, G.L. HAN- reous Harriers (Long-winged Harrier = 450 g White- SEN,AND P.C. SMITtl. 1987. Tinting of breeding and faced Ibis, Plegadischihi; Cinereous Harrier = 300 g ju- the seasonalimportance of passerineprey to North- venile European hare). However, the geometric mean ern Harriers (Circus cyaneus).Can. J. Zool. 65:1942- weight was similar (Cinereous Harrier = 31.2 - 5.5 g; 1946. Long-wingedharrier = 32.4 + 11.2 g). BO, M.S., S.M. CICCHINO, AND M.M. MARTINEZ. 1996. Diet Birds contributed most of the biomass in the diet of of Long-winged Harrier (Circusbuffoni) in southeast- both species,with a higher percentage for Cinereous ern BuenosAires Province,Argentina. J. RaptorRes'. Harriers (81%) than for Long-wingedHarriers (68%). 30:237-239. However, the speciescontributing most of the biomass CABRER^,A.L. AND E.M. ZARDINI. 1978. Manual de la flora were not the same. Cinerous Harriers ate mainly Eared de los alrededores de Buenos Aires. Editorial ACME Doves and Long-wingedHarriers ate mainly White-faced S.A.C.I., BuenosAires, Argentina. Ibis. CAMPERI, A.R. 1992. Estudio sobre aves colectadas en el extremo sudoeste de la Provincia de Buenos Aires RESUMEN.--Se estudi6 la dieta del Gavilfn Ceniciento Neotropica38:127-140. (Circus cinereus)durante dos periodos reproductivosen CANEVARI,M., P. CANEVARI,G.R. CAm•IZO, G. HARRIS,J. la Reserva Integral Laguna de Los Padres, Provincia de RODRIGUEZMATA, AND R.J. STRANECK.1991. Nueva Buenos Aires. E1 frea de nidificaciCn se encuentra en un gula de las Aves Argentinas. Fundaci6n Acindar, ambiente arbustivo circundado por campos cultivados, BuenosAires, Argentina. pasturas,montes, lagunas y freas suburbanas.Se recolec- CONTRERAS,J.R. 1979. Birds weights from northeastern taron 63 egagrCpilasy 45 restospresa, provenientesde Argentina. Bull, Br. Ornithol.Club 99:21-24. SEPTEMBER 2000 SHORT COMMUNICATIONS 241

DE LA PLEA,M.R. 1985. Guia de AvesArgentinas, Falcon- NAROSKY, T. AND A.G. DI GIACOMO. 1993. Las Aves de la iformes. Edici6n del antor, Santa F6, Argentina. Provinciade BuenosAires: distribuci6n y estatus.Aso- DEEHoYo, J., A. ELLIOTT,ANDJ. SARGATAL.lEDS.]. 1994. ciaci6n Ornitol6gica del Plata, Vazquez Mazzini Ed y Handbook of the birds of the world. Vol. 2. New L.O.L.A., Buenos Aires, Argentina. World vultures to guineafowl. Lynx Edicions, Barce- --AND D. YZURIETA. 1973. Nidificaci6n de dos circi- lona, Spain. dos en la zona de San Vicente (Pcia. de Buenos A•- FIORA,A. 1933. E1peso de las aves.Hornero 5:174-188. res). Hornero 11:172-176. GONZ3•LEZLOPEZ, J.L. 1991. E1 Aguilucho Lagunero Cir- --AND --. 1987. Gu/a para la identificaci6nde cusaeruginosus (L., 1748) en Espafia.Situaci6n, Biol- las Aves de Argentina y UruguayßAsoc. Ornitol6g•ca ogia de la Reproducci6n, Alimentaci6n y Conserva- del Plata, Buenos Aires, Argentina. ci6n. ICONA-•C.S.I.C, Madrid, Espafia. SAGGESE,M.D. AND E.R. DE LUCCA.1995. Reproducci6n GROSSMAN,M.L. ANDJ. HAMLET.1964. Birds of prey of del Gavilan Ceniciento Circuscinereus en la patagoma the world. Bonanza Books, New York, NY U.S.A. argentina. Hornero14: 21-26. HUMPHREY, P.S., D. BRIDGE, P.W. REYNOLDS,AND R.T. PE- S^LVADOR,S.A. 1988. Datos de peso de avesArgentinas. TERSON.1970. Birds of Isla Grande (Tierra del Fue- Hornero 13:78-83. go). Preliminary Smithsonian Manual. Smithsonian ß 1990. Datos de pesosde avesArgentinas 2. Hor- Inst., Washington,DC U.S.A. nero 13:169-171. JIMgNEZ,J.E. ANDE JAICSIC.1988. Ecologyand behaviorof --AND L.A. SALVADOR.1986. Nota sobre la reprod- southern South Aanerican Cinereous Harriers, Circus ucci6n del misto (Sicalisluteola) en C6rdoba, Argen- cinereus. Rev. Chil. Hist. Nat. 61:199-208. tina. Hornero 12:274-280. LANGONE,J.A. 1994. Ranas y saposdel Uruguay. Recon- SCHIPPER,WJ.A. 1973. A comparasionof' prey selection ocimiento y aspectosbio16gicos. Museo DamasoAn- tonio Larrafiaga, No. 5-Serie de Divulgaci6n. Monte- in sympatricharriers (Circus)in western Europe. Ger- video, Uruguay. faut 63:17-120. MARTI,C.D. 1987. Raptor food habits studies.Pages 67- W1TKOWS}tI,J. 1989. Breeding biology and ecologyof the 80 in B.A. Giron Pendleton, B.A. Millsap, K.W. Cline, Marsh Harrier Circusaeruginosus in the Barycz Valley, Poland. Acta Ornithol. 25:223-320. and D.M. Bird lEDS.], Raptor management tech- niques manual. Nat. Wildl. Fed., Washington, DC U.S.A. Received 6June 1999; 21 March 2000

J RaptorRes'. 34(3):241-243 ¸ 2000 The Raptor ResearchFoundation, Inc.

ABUNDANCEOF THE OGASAWARABUZZAI• ON CHICHIJIMA, THE PACIFICOCEAN

TADASHI SUZUKI AND YUKA KATO Departmentof BiologicalScience, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachi-ohji, Tokyo192-0397, Japan

KEYWORDS: Ogasawarabuzzard; Buteo buteo toyoshimai; and its longer beak and shorter wings and tarsi (Momi- Bonin; endemic,density. yama 1927). The Ogasawarabuzzard is listed as an endangeredspe- cies in Japan (Japan Environmental Agency 1998) be- The Ogasawarabuzzard (Buteobuteo toyoshimai) is an cause the population is so small. It is known to inhabit insular subspeciesof the Common Buzzard (B. buteo,Or- the two island groups of the Ogasawaras,Chichijima-ret- nithologicalSociety of Japan 1974, Brazil 1991, Monroe to, and Hahajima-retto (Brazil 1991), with total areas of and Sibley 1993). It is endemic to the Ogasawara(Bonin) 38.2 km9 and 27.0 km2, respectively(Ogasawara Natural Islands, which lie about 1000 km south of Tokyo in the Environmental Group 1992). Among the islands,Chich- Pacific Ocean. It usually nests on rocky cliffs (Funatsu ijima is the largestand probablysupports the largestpop- and Chiba 1991), although tree nestinghas been recently ulation of buzzards.It is also the most developedof the reported (Takagi and Ueda 1998, Kato and Suzuki1999). Ogasawara Islands with a human population of about It differs from a nearest subspecies,B. buteojaponicus,be- 1900 in 1998. In the early 1990s,the number of pairs of causeof its drab plumage with lessbrown on the uppers Ogasawarabuzzards on Chichijima was estimated to be