The tawny eagle (Aquila rapax) is a large bird of prey. Like all eagles, it belongs to the family Accipitridae. Its heavily feathered legs mark it as a member of the subfamily Aquilinae, also known as booted eagles.Helbig, A. J., Kocum, A., Seibold, I., & Braun, M. J. (2005). A multi-gene phylogeny of aquiline eagles (Aves: Accipitriformes) reveals extensive paraphyly at the genus level. Molecular phylogenetics and evolution, 35(1), 147-164. Tawny eagles have an extensive but discontinuous breeding range that constitutes much of the African continent as well as the Indian subcontinent, with rare residency in the southern Middle East. Throughout its range, it favours open dry habitats such as semideserts, deserts steppes, or savanna plains. Despite its preference for arid areas, the species seldom occurs in areas where trees are entirely absent.Hustler, K., & Howells, W. W. (1989). Habitat preference, breeding success and the effect of primary productivity on Tawny Eagles Aquila rapax in the tropics. Ibis, 131(1), 33-40. It is a resident breeder which lays one to three eggs in a stick nest most commonly in the crown of a tree.Naoroji, R., & Schmitt, N. J. (2007). Birds of prey of the Indian subcontinent. Om Books International. The tawny eagle is perhaps the most highly opportunistic of all Aquilinae, and often scavenges on carrion or engages in kleptoparasitism towards other carnivorous animals but is also a bold and active predator, often of relatively large and diverse prey.Brown, Leslie and Amadon, Dean (1986) Eagles, Hawks and Falcons of the World. The Wellfleet Press. . It is estimated that tawny eagles can reach the age of 16 years old. Nonetheless, precipitous declines have been detected throughout the tawny eagle's range. Numerous factors, particularly loss of nesting habitat due to logging and global warming, as well as persecution (largely via poisoning) and other anthropogenic mortality (largely through contact with various manmade objects) are driving the once numerous tawny eagle perhaps to the brink of extinction.Ogada, D. L. (2014). The power of poison: pesticide poisoning of Africa's wildlife. Annals of the New York Academy of Sciences, 1322(1), 1-20.
It is also the national animal of Ghana.
Taxonomy Dutch naturalist Coenraad Jacob Temminck described the tawny eagle in 1828 from an Indian type specimen.Temminck, C. J. (1828). Blik op de dierlijke bewoners van de Sunda-eilanden en van de overige Nederlandsche bezittingen in Indië. Bijdr. nat. Wetensch, 3, 64-78. "Tawny eagle" has been designated the official name by the International Ornithologists' Union (IOC). Aquila is Latin for "eagle" while rapax is also Latin for "to grasp", and relates to the word rapacious, i.e. highly predatory.Steyn, P. (1983). Birds of prey of southern Africa: Their identification and life histories. Croom Helm, Beckenham (UK). 1983.Brown, L. (1977). Eagles of the World. Universe Books. The tawny eagle is a member of the booted eagle subfamily (Aquilinae) within the Accipitridae family. The booted eagle clan are monophyletic and study of karyotypes has indicated that they likely have few to no close external relations within the overall extant accipitrid family.Li, Q., Lin, J., Li, S., Wang, Y., Li, W., & Zeng, Y. (2000). Studies on the evolution of mitochondrial DNA in 11 species of Accipitridae. Dong wu xue bao.[Acta zoologica Sinica], 46(2), 209-220.De Boer, L. E. M., & Sinoo, R. P. (1984). A karyological study of Accipitridae (Aves: Falconiformes), with karyotypic descriptions of 16 species new to cytology. Genetica, 65(1), 89-107. The booted eagle subfamily all have feathers covering their legs and are distributed in every continent that contains accipitrids. The genus Aquila has been traditionally defined as largish, dark-hued and long-winged eagles of open country.Väli, Ü. (2002). Mitochondrial pseudo‐control region in old world eagles (genus Aquila). Molecular Ecology, 11(10), 2189–2194. However, study of genetics have resulted in several reclassifications. These include the moving of smaller, paler and more forest-dwelling eagles in Aquila, the separation of the unique spotted eagles to the genus Clanga as well as the division of some small eagles to the genus Hieraeetus outside of Aquila. Furthermore, genetic research has further revealed a schism in superficially similar eagles between the tawny eagle and its close relatives and other superficially similar Aquila such as the golden eagle (Aquila chrysaetos) species complex. To date, the tawny eagle species group and golden eagle species group are still contained in the same genus despite the apparent lack of close relation.Lerner, H. R., & Mindell, D. P. (2005). Phylogeny of eagles, Old World vultures, and other Accipitridae based on nuclear and mitochondrial DNA. Molecular phylogenetics and evolution, 37(2), 327-346.
The tawny eagle was previously treated as conspecific with the migratory steppe eagle (Aquila nipalensis).Stresemann, E., & Amadon, D. (1979). Order Falconiformes. Check-list of birds of the world, 1, 271-425. These eagles were considered part of the same species as recently as 1991.Howard, R., & Moore, A. (1991). A complete checklist of the birds of the world (No. Ed. 2). Academic Press Ltd. The steppe and tawny eagles were split based on pronounced differences in morphology and anatomy. The steppe eagle is a larger bird, with a much more pronounced gape, and differs by appearance in its blockier frame, bigger wings and evinces different coloring at all stages of development, despite some morphs of the two eagles superficially resembling one another.Amadon, D., & Short, L. L. (1976). Treatment of subspecies approaching species status. Systematic Zoology, 25(2), 161-167.Brooke, R. K., Grobler, J. H, Irwin, M. P. S., & Steyn, P. (1972). A study of the migratory eagles Aquila nipalensis and A. pomarina (Aves:Accipitridae) in Southern Africa, with comparative notes on other large raptors. Occ. Papers of the Nat. Mus. of Rhodesia B5(2): 61–114. Furthermore, the respective species differ in ecology (dietary biology, nesting habits) and are strongly allopatric in their breeding ground distribution. Two molecular studies, each based on a very small number of genes, indicate that the species are distinct, but disagree over how closely related they are.White, C. M., Olson, P. D., & Kiff, L. F. (1994). Family Falconidae (hawks and eagles). Handbook of the birds of the world, 2: 52-214. Genetically, the tawny eagle may cluster more closely with the imperial eagle species complex despite the steppe eagle being more sympatric with those northerly Eurasian eagles.
Subspecies
There are three described races of tawny eagles. The subspecific classification of the species has at times been considered complicated by variations and existence of different morphs; in turn they were once considered tentative. However, each subspecies is largely allopatric in geography, the primary ambiguities lying in the northern part of east Africa where both African races may intergrade.Kemp, A.C. and G. M. Kirwan (2020). Tawny Eagle (Aquila rapax), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.
A. r. rapax; distributed in Africa from the southern Democratic Republic of the Congo and central Kenya to all points southwards. However, this race may range up to as far north as Ethiopia as well (thus likely intergrading considerably with the following subspecies which is widespread in Ethiopia).Ash, C. P., & Atkins, J. D. (2009). Birds of Ethiopia and Eritrea: an atlas of distribution. A&C Black. Adult often of this nominate subspecies are often relatively more strongly rufous in colour than other races and are sometimes dark streaked below. Meanwhile, the juvenile tends to be light rufous. wing chord lengths in this race have been measured at in males and in females. The mean wing chord length in two samples of A. r. rapax measured in males and in females.Musindo, P. T. (2012). Morphological variation in bills and claws in relation to Prey type in Southern African Birds of Prey (Orders Falconiformes and Strigiformes). The tail length of both sexes in A. r. rapax measures with a tarsus length of . Body mass can range roughly from in overall samples of at least 36 eagles. A. r. belisarius; this race resides in west Africa to Ethiopia and southwest Arabia as well as far south as the northern Democratic Republic of the Congo and northern Kenya.Clouet, M., Barrau, C., & Goar, J. L. (2000). The diurnal Afro-alpine raptor community of the Ethiopian Balé Highlands. Ostrich, 71(3-4), 380-384. This race is described to appear "neater" than the nominate subspecies, possibly due to this race often occurring in even more desert-like conditions than the other races and thus having more compact feathering.Cook, W. E. (2012). Avian desert predators. Springer Science & Business Media. It is when compared to the nominate, often duller and browner above, showing less of a rufous tinge. Meanwhile, individual pale morph of A. r. belisarius often a shade or two darker than pale nominate but not consistently so. Although said to be slightly larger, measurement data shows this subspecies to of broadly very similar size to the nominate race. In males, the wing chord is and, in females, the wing chord is . The mean wing chord lengths were reportedly in males and , which indicates a slightly less pronounced sexual dimorphism than in the nominate race. As for body mass, 1 male was found to weigh while three females weighed from . A. r. vindhiana; excluding the Arabian Peninsula, this race likely comprises all the tawny eagles found in Asia, such as in southeastern Iran and the Indian subcontinent. However, ambiguities exists on where the range of A. r. belisarius ends and of vindhiana begins, especially in Middle Eastern areas.Al-Sheikhly, O. F., & Al-Azawi, A. J. (2019). The Diurnal Birds of Prey (Raptors) in the Mesopotamian Marshes of Southern Iraq with notes on their Conservation Status. Bulletin of the Iraq Natural History Museum (P-ISSN: 1017-8678, E-ISSN: 2311-9799), 15(4), 381-402.Crochet, P. A., Raty, L., De Smet, G., Anderson, B., Barthel, P. H., Collinson, J. M., Dubois P.J., Helbig, A.J., Jiguet, F., Jirle, E., Knox, A.G., Le Maréchal, P., Parkin, D.T., Pons, J.-M., Roselaar C.S.,Svensson, L., van Loon, A.J., & Yésou P. (2010). AERC TAC's taxonomic recommendations. July 2010. Disponible sur: http://www. aerc. eu/tac. html. Sometimes A. r. vindhiana is suggested as full species.Sibley, C. G., & Monroe, B. L. (1990). Distribution and Taxonomy of Birds of the World. Yale University Press. This subspecies averages darker than either other race and usually is lacking in warmer rufous tone. In general, it is somewhat more similar in hue to the steppe eagle. Adult irises are sometimes brown in A. r. vindhiana (again reminiscent of the steppe eagle). The pale morph of this race is greyer and less rufous than African tawny eagles, although generally juveniles and immature are sometimes more rufous. It may be marginally the smallest subspecies, although in general the tawny eagle evinces remarkably little size variation across its wide range. Wing chord measurements are in males and .Ali, S., & Ripley, S. D. (1980). Handbook of the birds of India and Pakistan, together with those of Bangladesh, Nepal, Bhutan, and Sri Lanka. Oxford University Press.Baker, E. C. (1928). Fauna of British India including Ceylon and Burma. Taylor & Francis. In males, the wing chord reportedly averages about and in females, it averages . In males the tail length is and in female it is . The tarsus length of male A. r. vindhiana is and in females is . Unsexed adults in India weighed from .
Description