Aquila Hastata S
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lbis (2002), 144, 665-675 On the taxonomic status of the lndian Spotted Eagle Aquila hastata S. J. PARRY,I*W. S. CLARK2a v. pnRxRsH3 l Bird Group,Department of Zoology,The NaturalHistory Museum, Tring, Herts. HPn 6Ae UK and Departmentot Biology,Darwin Building, ' University College London, Gower Street,London WCl E 68T UK 2POBox 531467Harlingen, TX 78553,USA 38wHS,331 Rajendra Magar, Bharatpur, Rajasthan, 321 001lndia We review the status of the two currently recognized subspecies of Lesser Spotted Eagle Aquila p. pomarina (western Eurasia) and A. p. hastata [Indian subcontinentJ on the basis of museum diagnosis and field observations.We present differences between these two allopatric taxa which demonstrate that they should be treated as distinct species. Specifi- cally, we present evidence of differences in plumage ftoth for adults and luveniles), external morphology, osteology, clutch size and behaviour. Particular emphasis is placed on differ- ences in gape size and general cranial structure. Most recent authorities have recognizedonly two by Brehm (1831).Lesson, who appearsto havebeen speciesof'spotted eagles'(hereafter spotted eagles): unawareof the latter description,described in detail the monotypic Greater Spotted EagleAquila clanga the spottedplumage of immaturesand also noted that Pallas,l8l I and the polytypic LesserSpotted Eagle hastataexhibits an exceptionallylarge gape,stating: A. pomarinnBrehm, l83l 1965, Brown & 'La fVaurie commissurede la boucheest d'une trds grande Amadon 1968,Cramp & Simmons1980,Amadon ampleur; elle se trouve borde€ par un repli epaiset & Bull 1988,Sibley & Monroe 1990,del Hoyo et al. commecartilagineux, et s'etendjusque sous l'oeil. Elle I 994). However,earlier generationsof ornithologists a 2 poucesde longueurde l'onglei la pointedu bec.' treated the two subspeciesof the Lesser Spotted Eagle [migratory pomarirn, which breedsin western These important observationsappear to have been Eurasiaand winters in Africa, and sedentaryhastata ovedookedsubsequently. Lesson,1834 of the Indian subcontinent)as distinct A decadeafter the publication of Lesson'sdescrip- species(Blfh 1846, Hume 1873, Sharpe 1874, tion of hastata, Blyth I I B4 3 ) describedit asLimnaetus Anderson 1875a, 1875b,Blanford 1895, Whistler unicolor,this was later synonymized as Limnaetus 1930,Swann 1933, Baker 1935). More recendy,some hastatusin deferenceto Lesson'soriginal description authorities [e.g.Vaurie 1965, Cramp & Simmons [Blyth I 844).Jerdon (1844), followed by Gray(1845), 1980, del Hoyo et al. 1994) have suggestedthat the referredthe taxon to the genusSpizaetus.Aperiod of taxonomic status of pomarina and hastatashould taxonomic consensusthen followed with first Blyth be reviewed.The failure to recognizespecies due to (1846), and subsequentlyHume (1873),Anderson inconsistent taxonomy may have important impli- (1875a,1875b) and Sharpe(1874) recognizing the cationsfor conservationmanagement (e.g. May 1990, taxon asthe specificallydistinct.4quila hastata. Hazevoet 1996) and, in recent years,a number of Brooks(1873) noted somesuperficial similarities authorities have emphasizedthe general need to between hastata and pomarina, which led him to reassessspecies limits in polytypic species[e.g. Zink regard the two taxa as synonymous;he combined & McKittrick 1995,Foggo er al.1997,Zink1997). them asA. naeui"a.Late4 howeveqafter examininga Aquil"ahastata was first describedfrom specimens largersample that included more immatures,Brooks from Bengalas Morphnus hastatus by Lesson( I 834) Q876) wrote that he had been mistaken in this three years afterA. pomarinawas formally described union. Furtheq,he enumeratedthe many differences between the taxa as the reasonfor their separate *Corresponding author. speciesstatus. Other authorities (e.g.Blanford 1895) Email: [email protected] maintainedthe separatestatus of the two eaglesuntil @ 2002 BritishOrnithologists' Union 666 S.J.Parry, WS Clark& V.Prakash Hartert (1914-1922) reclassified hastata as a race breeding hastata have been observed in Keoladeo of A. pomarina. This reclassification conformed to National Park (27"7 .6'-27 " 72.22'N and 77 "29.5' - Hartert's theoretical perspectives on avian taxonomy 77"33.9'E),Bharatpur, India, annually since 1986 and systematics following wider acceptance of tV.P.). Detailed breedingstudies were conducted the trinomial [cf. Stresemann 1975, Haffer 1992). from a hide I 5 m from the nest during three seasons Hartert dld acknowledge differences in the juvenile fPrakash1996). Tens of hastatawere observedin plumages of the two taxa but did not mention partsof India and Pakistan[VP.,W.S.C.; Clark & Khan differences in gape size, behaviour or breeding bio- 1995).Tens of thousandsof pomarinahave been logy. Swann (1920) followed this treatment, but later observedover many yearsin Israeland southernAfrica fSwann 1933) in a more detailed work reversed W.S C.). Many individualswere photographedin himself and joined Whistler (1930) and others in the field and captivity and examinedin the hand and again consideringhastata as a distinct species.Peters nest[W.S.C. &V.P.). [1931, i940), on the other hand, followed Hartert (1914-1922) in treating hastata asa race of A.poma- RESULTS rina.Tbis is the treatment that has met with uncriti- cal acceptance for the last six decades. In this paper Major plumage and iris colour differencesbetween we demonstrate differences between hastata and adults and juveniles of hastata andpomarin4 were pomarinathat clearly indicate that these two allopat- identified and are summarizedin Table l. The two ric taxa should be considereddistinct speciesregard- taxa differ markedlyin both adult andjuvenile plum- lessof speciesconcept. agesand probably alsoin older immature plumages, but no certainmuseum specimens of hastataof these ilETHODS ageswere found. Statistical analysis of eight rostral biometrics External characters were examined on museum skins revealedsignificant differences[P < 0.05) between of pomarina [200+), hastata Q00+) anddanga [300+) pomarina andhastata flable 2). Specifically,hastata [mainly S.J.P.,but also W.S.C. & V.P.). Plumage has a broader rostrum and a shorter mandibular colours of skins were recorded according to Munsell symphysisthanpomarina. Howeveq the rnoststriking Q973) colour charts. Morphometric analyseswere differencebetween the two taxa is in the size of made of measurements taken from sftns of pomaina the gape:hastata has a much larger gapethan does (n = 36), hastata (n = 5 1) and clanga (n = 47) in the pomarina,even larger than that of A. danga (Fig. l). collections of the Natural History Museum (BMNH). Differencesin the rostro-cranialmorphology of the Measurements were taken with dial callipers and a spotted eaglesare alsoemphasized by the results of steel rule. The sex of museum skins was determined a PCA of theseeight rostral biometrics ffable 3 and from labels, or, in the absence of these data, by the Fig 2). The eigenvectorsindicate that PCI is a'size- multivariate methodology of Bortolotti [l984a, determined'axis (sensz Shea 1985), and that PC2 is 1984b). Two osteologicalspecimens of hastata were an index of rostro-cranialbreadth. All three taxa differ compared with three each of pomarina and clnnga. significantly [P < 0.05) in both rostro-cranial size Statistical analyseswere done using SPSS10.0 (SPSS IPC I ) andbreadth (PCz).Whil st hastatais interme- 1999a, 1999b). Interspecific and intraspecific sex diate betweenthe other taxa in PCI scores,it hasthe differences in biometrics were tested for by one-way highestPC2 scores.Specifically, hastata has a longer ANovAs and a post hoc test for unequal sample sizes: rictus than either of the othersand its caudalmargin Hochberg's GT2 test (Sokal & Rohlf l98l). Prin- extendsbeyond the eye,a feature not presentin the cipal Components Analysis (PCA) of a covariance others.This feature is obvious,even in the field, as a matrix of log-transformed data was used in inter- pronouncedwide flangeor'lip' [Fig.3). preting rostral differences and similarities of the three Further differences in cranial structure are also taxa. The significance of differences between sexes evident from t}re analysisof skeletal specimens.In and taxa in PCA scores were tested by one-way hastatathe palatinum is very broad; this element is ANovAs and Hochberg's GTZ tests. Clutch sizeswere far narrower in the other species(Fig. 4). The jugal determined from literature review, clutch record bars(sensz Bock 1964) of hastataare strongly bowed cards in the BMNH, and field observation by V.P. but straight in pomarina and clanga (Fig.4). The The results of museum specimen analyses were mandible is also strongly bowed in hastata and supplemented by field observations. Two pairs of the symphysisreduced, whilst in the other taxa the @2002 British Ornithologists' Union, /bls, 144, 665-675 Taxonomic status of the lndian Spotted Eagle 667 Tabfe 1. Principal plumage and iris colour differencesbetween hastata and pomarina. Character Age hastata pomarina Head colour Adult Uniformlyvery dark brown (10 YR2l2)- Palerbrown (10 YR 5/4) crown and nape withblack shaft streaks withoutblack shaft streaks Backand upperwing coverts Adult Sameas above Backdarker brown (10 YR 3/2) than head andcoverts Underuvingcoverts Adult Lessercoverts paler brown (10 YR 7/3), Greatercoverls darker yellowish brown othersuniform (10YR 5i4),others uniform Undertailcoverts Adult Uniformpale brown (10 YR 6/3) with buff baning Brown(10 YR 5/3) with pale tips lriscolour Adult Brown Yellodamber Nape Juvenile No rufouspatch Rufous/strongbrown