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The gray hawk (''Buteo plagiatus'') or Mexican goshawk is a smallish raptor found in open country and forest edges. It is sometimes placed in the genus ''Asturina'' as ''Asturina plagiata''. The species was recently split by the American Ornithologists' Union (AOU) from the gray-lined hawk. The gray hawk is found from Costa Rica north into the southwestern United States. The grey hawk is in length and weighs on average. The adult has a pale gray body, the tail is black with three white bands and the legs are orange. It is a solid, unpatterned gray on the upper parts. Immature birds have dark brown upperparts, a pale-banded brown tail, brown-spotted white underparts and a brown streaked buff head and neck. This species is quite short-winged, and has a fast agile flight for a ''Buteo''. The call is a shrill whistled ''kleee-ooo''. Gray hawks feed mainly on lizards and snakes, but will also take small mammals, birds and frogs. It usually sits on an open high perch from which it swoops on its prey, but will also hunt from a low glide. The nest is of sticks and built high in a tree. The usual clutch is one to three, usually two white to pale blue eggs.〔(【引用サイトリンク】title=Animal Diversity (Asturina nitida) )〕 The young take about 6 weeks to fledging. ==Taxonomy== The taxonomy of the gray hawk puts it within in the genus ''Buteo''. This genus consists of hawks, which include the red-shouldered hawk, Swainson's hawk, and others. The genus ''Buteo'' is in the sub-family Accipitrinae which is also known as the "true hawks", and Accipitrinae is within the family of Accipitridae. Accipitridae consist of hawks, old world vultures, kites, harriers, and eagles. This family is within the order Falconiformes which are the diurnal (active during the day) birds of prey.〔The American Ornithologist Union. (2013). (List of the 2,046 Bird Species (With Scientific and English Names) Known From the A.O.U. Check-List Area ). The American Ornithologist Union. Retrieved November 10, 2013〕 The species was originally described by Hermann Schlegel in 1862 as ''Asturina plagiata''. The AOU listed ''A. plagiata'' with the common name "Mexican goshawk" in the first four editions of the ''Check-List of North American Birds'', from 1886–1931.〔 By the 1957 fifth edition, it had been merged into ''Buteo nitidis''; but by the 1998 seventh edition all of ''B. nitidis'' was separated into the resurrected genus ''Asturina''.〔 In 2003, Riesing et al.〔 (publisher's abstract and metadata (Elsevier) ) (author's PDF )〕 published results of research on nucleotide sequences within the mitochondrial ''nd6'' gene and pseudo-control-region for all species of ''Buteo'' and several related species. Among other findings, they recommended that ''Asturina'' be merged into ''Buteo'', and concluded that ''A. nitidis plagiatus'' was sufficiently different from ''A. n. nitidis'' and ''A. n. costaricensis'' to be considered a separate species. In 2005, the AOU's Committee on Classification and Nomenclature – North America decided〔 Full text via (BioOne ).〕 to follow the recommendation to merge the genera, but was not convinced about splitting the species. The gray hawk was originally ''Asturina nitida'' but controversy existed between ornithologists on whether or not this species was closely enough related enough to put it in the ''Buteo'', but chromosomal mapping in 2013 has proved that the gray hawk is within the Buteoninae.〔de Oliveira E.H.C, Tagliarini M.M, dos Santos MS, O'Brien P.C.M., Ferguson-Smith M.A. (2013) Chromosome Painting in Three Species of orButeoninae: A Cytogenetic Signature Reinforces the Monophyly of South American Species. PLOS ONE.〕 Researchers such as de Oliveira, Tagliarini, dos Santos, O'Brien, and Ferguson-Smith proposed in 2011 that the gray hawk should be two different species, because of a slight difference in plumage color and a difference in alarm calls documented in the northern and southern distributional gap in Costa Rica. They suggest that the species is better split into the gray-lined hawk (''Buteo nitidus'') and the gray hawk (''Buteo plagiatus''),〔Millsap, B.A, Seipke S.H., Clark W.S. (2011). The Gray Hawk (Buteo Nitidus) is Two Species. Condor. 113(2), pp. 326–339. (abstract ), (full text ), (PDF )〕 but the American Ornithologist Union does not recognize the gray hawk as two different species. So far under the size range criteria this species' population is not vulnerable. 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「Gray hawk」の詳細全文を読む スポンサード リンク
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