MARCH 2003 SHORT COMMUNICATIONS 75

[ED.], Fossil vertebrates from the Bahamas. Smithson. Caracaracreightoni Brodkorb based on fossilsfi'om the Contrib. Paleobiol. 48. Quaternary of Cuba (Aves:Falconidae). Proc.Biol. Soc RAFFAELE,H.A., J. WILEY,O. GARR1DO,A. KEITH,AND J. Wash. 114:501-508. RAFFAELE.1998. A guide to the birds of the West In- -- ANt)--. 2003a. A new speciesof caracara(Mzl- dies. Princeton Univ. Press,Princeton, NJ. vago)from Quaternary asphaltdeposits in Cuba, w•th SUAREZ, W. 2000. Gontribuci6n al conocimiento del es- notes on new material of Caracaracreightoni Brodkorb tatus genarico del c6ndor extinto (Giconiiformes: (Aves:Falconidae). Proc. Biol. Soc. Wash. 16: in press Vulturidae) del Guaternario cubano. Ornitol.Neotrop. --AND --.. 2003b. New records of storks (Cico- 11:109-122. niidae) from Quaternary asphalt deposits in Cuba --AND O. ARREDONDO. 1997. Nuevas adiciones a la Condor 105:150-154 paleornitologia cubana. Pitirre 10:100-102. WETMORE,A. 1937. Bird remainsfrom cavedeposits on -- ANDS.L. OLSON.2001a. A remarkablenew species Great Exuma Island in the Bahamas.Bull. Mus. Comp. of small falcon from the Quaternary of Guba (Aves: Zool. 80:427-441. Falconidae: Falco). Proc. Biol. Soc. Wash. 114:34-41. --AND --'. 200lb. Further characterization of Received22 July 2002; accepted28 November 2002

j. RaptorRes. 37 (1) :75-77 ¸ 2003 The Raptor ResearchFoundation, Inc.

SUBADULT AND PALE STEPPE EAGLES BREEDING IN MONGOLIA

DAVID H. ELLIS 1 USGSPatuxent Wildlife Research Cente•; 11410 AmericanHolly Drive, Laurel, MD 20708 U.S.A.

KEYWORDS: SteppeEagle;, Aquila nipalensis. placement (i.e., newly grown) feathers are light or dark before concludingthat the Steppe Eagle has a pale adult All adult Steppe Eagles (Aquila nipalensis)are report- morph. Although subadultsof some speciesof Aquila ea- edly very dark (Ferguson-Leesand Christie 2001). How- gles are known to at least occasionallybreed (e.g., New- ever, the closely related (Wink and Sauer-Gfirth 2000) ton 1979,Steenhofet al. 1983), I knowof no prior record Tawny Eagle (A. rapax) does have a pale adult morph of a subadultSteppe Eagle breeding. (see Plate 114, Brown and Areadon 1968). Clark (1992) During five expeditionsto Mongolia from 1994-2000, decried the confusion in the scientific literature and in I found more than 20 Steppe Eagle nests.At one site •n museum collections over the various morphs of the arid southeasternMongolia (115øE, 45øN), we found a Steppe and Tawny eagles and advanced "criteria for the very pale bird (Fig. 1). Elsewherewe found two rufous- correct identification of all museum specimensand live plumagedbirds. All three were attending live young. One birds .... "He statesconclusively that SteppeEagles be- of the rufous birds was captured (Ellis et al. 2001) and come "much darker as adults." His assertion stems from photographed in hand. The very pale bird was photo- fieldwork in Israel, India, and Africa, and, more impor- graphed on its nest at a distance of 2 m. tanfly, from handling over 300 museum specimens.His In Mongolia, Steppe Eagle adults are generally deep conclusionreaffirms statementsby Cramp and Simmons chocolatebrown above and below with blackishremiges (1980) that subadultsare paler than adults and that all and rectrices finely barred with black. These dark birds very pale birds are young. match Glark's (1992, 1996) descriptions of the dark While it is helpful to examine migrantsand wintering brown adult plumage. The only consistentlypresent light birds in evaluating the prevalenceof adult morphs, evi- area in the plumage of dark adults is a broken line of dence to support the claim that no adults are pale must whitish spotson the upper tail coverts.This line is readdy come from the breeding grounds.Even there, if very pale visible at great distanceswhen a bird is flying, except breeders are found, it is necessaryto determine if re- when overhead.Some dark birds (probably thosetoolung from subadult plumage) show a dappled line of light brown at the trailing edge of the under wing coverts. l Present address:USGS SouthwestBiological Science Under some light conditions, pale areas at the base of Center, HC 1 Box 4420, Oracle, AZ 85623 U.S.A.; e-mail the primaries are apparent on the underside of the wings address: dcellis@theriver. com of some, and probably all, dark adults. The head is gen- 76 SHORT COMMUNICATIONS VOl,. 37, NO. I

Figure 1. Pale Steppe Eagle at its nest in southeasternMongolia. This bird resemblesthe adult pale morph of the Tawny Eagle as illustrated byJ. Harrison (Brown and Amadon 1968:649) and appears identical to a pale subadult or adult Tawny Eagle photographedat the nest by P. Steyn (1973:54-55). Note metal trash in nest, a conspicuous,and sometimesdangerous, feature of Steppe Eagle nestsacross Mongolia (Ellis and Lish 1999). The lower photo includes a hatchling and 1 egg. This photo alsoshows two generationsof feathers (most conspicuousin the anterior scapulars); feathers of both generationsare worn (suggestingthat this bird is at least 2 yr old) and both are very light (dem- onstratingthat in this individual light plumage wasretained). The upper photo showspale tips on rectrices,"tertials," and secondaries, a characteristic common to all juvenile Steppe Eagles. This bird fits Clark's (1992) gray-brown morph, frequently seen in Steppe Eaglesfor the first 3 or 4 yr. M_XRCH 2003 SttORT COMMUNI(LATIONS 77

erally uniforlnly dark, but, as stated by Cra•np and Sim- probablemente, esta representa un ave reproductora de mons (1980), some birds show light (buff) hackles on 2-, 3-, o 4 aftos de edad. the nape or back of the head. One extremelypale-head- ed, but otherwisedark, adult from central Mongolia was ACKNOWLEDGMENTS observedat close range while it perched on the nest rim. It displayeda light area on its head and napejust as pale Our travels were financed largely by NASA-Goddard Space Flight Center and USGS Patuxent Wildlife Re- as in most adult Golden Eagles (A. chrysaetos). searchCenter with supplementalsupport from the Insti- In contrastto the extremelydark adultsthat are typical tute fbr Raptor Studies, NAP,C-United Arab Emirates, for Mongolia, our blond breeder (Fig. 1) was uniformly Howell Wynne, and an anonymousphilanthropist. Tsen- pale buff on the whole mantle, head, and upper wing geg Purevjavserved as my primary translator.Merlin Elhs coverts. Only the remiges, rectrices, and distal scapulars assistedin the field. William S. Clark kindly i•nprovedthe were heavily pigmented. Even though the rectrices and manuscript and identified the birds (from photographs) secondarieswere dark, they showed pale tips and pale as subadult.All threeJRR reviewers,Rob Simmons,Keith basal barring and were, therefbre, much lighter than Bildstein, and D. Peplet deserve mention not only for those of dark adults.W. Clark (pets. comm.) compared commentson the text but alsofor improvinglogic. photographsof this bird with his publisheddescriptions of various age classes(Clark 1992, 1996) and concluded LITERATURE CITED that this bird was subadult. Indeed, it closelymatches the third/fourth-year Steppe Eagles illustrated by Ferguson- BROWN,L. ANDD. AMADON.1968. Eagles,hawks, and fal- Lees and Christie (2001). cons of the world. McGraw Hill, New York, NY U.S A. The key plumage features leading to the conclusion CLOmK,W.S. 1992. The taxonomy of Steppe and Tawny that the bird was not adult are the pale tips of the rec- Eagles,with criteria for separationof museum spec•- trices and secondaries,very evident in the photographs xnensand live eagles.Bull. Br. Ornithol.Club 112:150- (Fig. 1). In the pale morph of the TawnyEagle, extensive 157. pale tips reportedly are present only on juveniles. How- --. 1996. Aging Steppe Eagles.Birding V•Md 9:268- ever,Steyn (1973) photographeda breeding,pale morph 274. Tawny Eagle with pale tips of secondariesand rectrices CPO.MP, S. •d'qDK.E.L. SIMMONS.(EDS.) 1980. Handbook just as seenin our pale bird from Mongolia. Further, Fer- of the birds of Europe, the Middle East, and North guson-Leesand Christie (2001) illustrate the pale morph Africa. Oxford Univ. Press, Oxford, U.K. adult Tawny Eagle with pale tips. Hence the confusion: ELLIS,D.H. XNDJ.W. LISH. 1999. Trash-causedmortality was this bird a subadultbreeder or do both specieshave in Mongolianraptors. Ambio 28:536-537. extremely pale adultswhich showbroad, light tips to the rectricesand secondaries?However, the rarity of records --, S.L. MOON, ANDJ.W. ROBINSON.2001. Annual of blond Steppe Eagles breeding (i.e., this is the only movementsof a Steppe Eagle (Aquila nipalensis)sum- record now documented) stronglysuggests that the pale xneringin Mongolia and wintering in Tibet. J. Bombay bird was not an adult. Nat. Hist. Soc. 98:335-340. Our two intermediate morph breeders match the ru- FERGUSON-LEES,J. •d,4o D.A. CHInSTIE.2001. Raptors of fous-tawny,subadult morph described by Clark (1992). the world. Houghton Mifflin, Boston,MA U.S.A. As such, these two records substantiatebreeding in sub- NEWtOn,I. 1979. Populationecology of raptors.Buteo adult plumage and add the Steppe Eagle to the list of Books, Vermillion, SD U.S.A. Aquila eagles that breed in subadult plumage. However, PHILLIPS,R.L., J.L. CUMMINGS,AND .I.D. BERRY.1991. Re- there is a remote possibilitythat the refous-tawnyeagles sponses of breeding Golden Eagles to relocation. and the blond eagle may have been replacement birds Wildl. Soc. Bull. 19:430-434. (Phillips et al. 1991), not the biological parents of the STEENHOF,K., M.N. KOCHERT,AND J.H. DOREMUS.1983. young in the nests. Nesting of subadult Golden Eagles in southwestern Idaho. Auk 100:743-747. RESUMEN.--Unaforma pftliday dos oscurasde ftguilade STEYN,P. 1973. Eagle days:a study of African eaglesat las estepas(Aquila mpax) rueton observadasen medio de the nest. Purnell & SonsSouth Af•ica,.Johannesburg, 20 parejas encontradasanidando en Mongolia. Todas las South Africa. tres estaban cuidando juveniles vivos.Las caracterlsticas WINK, M. AND H. SAUER-GI•IRTH. 2000. Advances in the del plumaje de las aves de color caf• rojizo--tostado su- molecular systematicsof African raptors. Pages 135- gieren que no eran adultos. En consecuenciala anida- 147 in R.D. Chancellor and B.-U. Meyburg [EDS.], ci6n de subadultosdel •tguila de las estepas (Aquila ni- Raptors at risk. WWGBP/Hancock House, Blaine, WA palensis) es documentada. La anidaci6n tambi•n se U.S.A. document6 para un ave de fase pfdida, pero la edad de estaave es incierta; tampoco se sabesiesta era la primera forma p•lida adulta conocida para la especie o, si mas Received4 February 2002; accepted 10 November 2002