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The crowned eagle, also known as the African crowned eagle or the crowned hawk-eagle (''Stephanoaetus coronatus'') is a large bird of prey found in sub-Saharan Africa; in Southern Africa it is restricted to eastern areas.〔Sinclair & Ryan (2003). ''Birds of Africa south of the Sahara. ISBN 1-86872-857-9〕 Its preferred habitats are principally riparian woodlands and various forests.〔 The crowned eagle is the only extant member of the genus ''Stephanoaetus''. A second species, the Malagasy crowned eagle (''Stephanoaetus mahery'') became extinct after humans settled on Madagascar.〔Goodman, Steven M. (1994). ''Description of a new species of subfossil eagle from Madagascar: Stephanoaetus (Aves: Falconiformes) From The Deposits Of Ampasambazimba''. Proceedings of The Biological Society of Washington 107(3): 421–428 ISSN 0006-324X () ()〕 At least 90 per cent of the diet is mammalian;〔Mitani J.C. , Sanders W.J., Lwanga J.S. & T.L. Windfelder (2001) "Predatory behavior of crowned hawk-eagles (''Stephanoaetus coronatus'') in Kibale National Park, Uganda" ''Behavioral Ecology and Sociobiology'' 49(2–3): 187–195 〕〔(African Crowned Eagle ). Sfzoo.org. Retrieved on 2012-08-22.〕 the usual prey taken by populations shows pronounced regional differences. Throughout its range the principal prey items are small ungulates (such as duikers, chevrotains), rock hyrax and small primates such as monkeys.〔Kemp, A. C. (1994). ''Crowned Hawk-eagle (Stephanoaetus coronatus)''. Pp. 205 in: del Hoyo, Elliott & Sargatal. eds. (1994). ''Handbook of the Birds of the World'', vol. 2. ISBN 84-87334-15-6〕 Birds and large lizards are barely taken.〔 Although the crowned eagle's long tail imparts an overall length up to , it is somewhat less massive and has a considerably shorter wingspan than Africa's largest eagle, the martial eagle (''Polemaetus bellicosus''). It is nevertheless considered Africa's most powerful eagle when measured in terms of the weight of its prey items.〔 It often preys on mammals such as bushbuck (''Tragelaphus scriptus''), exceptionally weighing up to albeit usually much less.〔〔Ferguson-Lees & Christie (2001). Raptors of the World. ISBN 0-7136-8026-1〕 The crowned eagle possesses unusually large talons and strong hindlegs, and may kill by crushing the skull. The eagle is also ferocious; some records from beneath a nest show the remains of a large, male Sooty mangabey weighing .〔McGraw, W. S., Cooke, C., & Shultz, S. (2006). ''Primate remains from African crowned eagle (Stephanoaetus coronatus) nests in Ivory Coast's Tai Forest: Implications for primate predation and early hominid taphonomy in South Africa''. American journal of physical anthropology, 131(2), 151-165.〕 Due to their ecological similarities, the crowned eagle is Africa's best analogue of the harpy eagle (''Harpia harpyja''). Thanks to its bold and highly conspicuous behavior, it is exceptionally well-studied for a large, forest-dwelling eagle. Due to a relatively high level of habitat adaptability, it was until recently considered to be faring well by the standards of large, forest-dependent raptors.〔Dowsett-Lemaire, F. & Dowsett, R.J. ''The Birds of Malawi: An Atlas and Handbook''. 2006, Tauraco Press and Aves, Liège, Belgium. 556 pages〕 However, today it is generally thought that it is decreasing far more than was previously perceived due to the almost epidemic destruction of native tropical African forest.〔 It is now listed as Near Threatened. == Taxonomy and systematics == This species was first described by Linnaeus in the ''12th edition of Systema Naturae'', published in 1766, as ''Falco coronatus''. Since birds were grouped largely on superficial characteristics at that time, many unrelated species were grouped by Linnaeus in the ''Falco'' genus. The actual taxonomic alignment of the crowned eagle is apparent due to its feathering over its tarsus, which is generally rare in unrelated accipitrids. The crowned eagle is actually part of the diverse “booted eagle” group, which has sometimes been considered a distinct subfamily (''Aquilinae''). Included in this grouping are the ''Aquila'' genus and all species described as “hawk eagles” including the genera ''Spizaetus'' and ''Nisaetus''. Other assorted monotypical genera included amongst “booted eagles” are ''Lophaetus'', ''Polemaetus'', ''Lophotriorchis'' and ''Ictinaetus''. At one time, the ''Stephanoaetus'' genus was considered a “specialized offshoot” of the ''Spizaetus'' hawk-eagles based on morphological attributes.〔''Eagles, Hawks and Falcons of the World'' by Leslie Brown & Dean Amadon. The Wellfleet Press (1986), ISBN 978-1555214722.〕 DNA sequences utilizing one mitochondrial and three nuclear genes indicated the crowned eagle is a sister species to the Asian hawk-eagles, which are now considered a separate genus, ''Nisaetus'', that are not closely related to the neotropical hawk-eagles, which are retained in ''Spizaetus''. However, another recent study, this time of sequences of two mitochondrial and one nuclear genes, did not reveal a close relationship of this eagle to any other accipitrid, including the ''Nisaetus'' species, and the genus was found to be genetically highly divergent from other "booted" eagles”. In a case of convergent evolution, the much heavier harpy eagle, which is outside of the “booted eagle” group, has a similar skeletal morphology to the crowned eagle.〔 Two less well-known, probably distantly-related species, the mountain hawk-eagle (''Nisaetus nipalensis'') and the black-and-chestnut eagle (''Spizaetus isidori''), have also been found comparable to the crowned eagle.〔 While both are slimmer and smaller, these eagles are also large-bodied, strong-footed offshoots of the evolutionary radiation of forest-dwelling booted eagles, respectively distributed in East Asia and South America. The adult crowned eagle even has somewhat intermediate appearance between these birds, sharing the variable patterning of the mountain hawk-eagle and some of the colouring of the black-and-chestnut.〔〔 Until possibly up to 1500, another crowned eagle species, the Malagasy crowned eagle (''S. mahery'') existed. Similar in size and form to the extant crowned eagle, the Malagasy crowned eagle probably filled a similar niche in Madagascar, but was likely to have preyed on lemurs in place of monkeys.〔 Apparently, the Malagasy crowned eagle became extinct due mainly to the loss of prey and habitat change, attributable to early humans on the island.〔Goodman, S. M., Rasoloarison, R. M., & Ganzhorn, J. U. (2004). ''On the specific identification of subfossil Cryptoprocta (Mammalia, Carnivora) from Madagascar''. ZOOSYSTEMA-PARIS-, 26(1), 129-143.〕〔Bustamante, J. S24. 3: ''Ecological factors affecting hunting behaviour during the post-fledging dependence period of raptors''.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「crowned eagle」の詳細全文を読む スポンサード リンク
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