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The beautiful nuthatch (''Sitta formosa'', sometimes called ''Callisitta formosa'') is a bird species in the family Sittidae. It is a large nuthatch, measuring in length, that is not sexually dimorphic. Its coloration and markings are dramatic, the upper parts being black and azure, streaked with white and pale blue on the head and lined with the same colors on the wing feathers. The underparts are orange, and the eyebrow and throat are ochre. An irregular, dark eyestripe highlights its eye. ''S. formosa''s ecology is not fully described, but it is known to feed on small insects and larvae found on the trunks and epiphyte-covered branches of trees in its range. Reproduction takes place from April to May; the nest is placed in the hole of an oak, rhododendron, or other large tree. The nest is made of plant material and fur in which the bird typically lays four to six eggs. Although the species is found in most of the countries making up the mainland of Southeast Asia, it appears to be rare throughout its range, its population being highly localized where it is found. The bird nests predominantly in mountain forests at an altitudinal range from up to nearly , with some seasonal height adjustment, down to around in winter. Its apparent localization within its range makes rigorous estimates of its population difficult, but its habitat is threatened by deforestation and the species appear to be in decline. It has been classified as vulnerable by the International Union for Conservation of Nature. == Taxonomy == The nuthatches constitute a genus – ''Sitta'' – of small passerine birds belonging to the family, Sittidae, typified by short, compressed wings and short, square 12-feathered tails, a compact body, longish pointed bills, strong toes with long claws, and behaviorally, by their unique head-first manner of descending tree trunks. Most nuthatches have gray or bluish upperparts and a black eyestripe. ''Sitta'' is derived from the Ancient Greek name for nuthatches, σιττη, ''sittē''. "''Nuthatch''", first recorded in 1350, is derived from "nut" and a word probably related to "hack", since these birds hack at nuts they have wedged into crevices. The genus may be further divided into seven subgenera, of which the beautiful nuthatch is placed alone in ''Callisitta'' (Bonaparte, 1850), and the species is therefore sometimes called ''Callisitta Formosa''.〔 The beautiful nuthatch was first described in 1843 by British zoologist Edward Blyth, from a specimen he examined in Darjeeling. Its kinship with other members of the genus is unclear. The bright blue color of its plumage invites a comparison to the blue nuthatch (''S. azurea''), or other blue-tinted nuthatch species such as the velvet-fronted nuthatch (''S. frontalis''), yellow-billed nuthatch (''S. solangiae'') and the sulphur-billed nuthatch (''S. oenochlamys''), but its distribution being focused in the eastern Himalayas, and the uniqueness of its plumage, argues against the assumption. According to the International Ornithological Congress and ornithologist Alan P. Peterson, no subspecies have been identified.〔(【引用サイトリンク】work=International Ornithological Congress World Bird List, Version 4.2 )〕 In 2014, Eric Pasquet, ''et al''. published a phylogeny based on examination of nuclear and mitochondrial DNA of 21 nuthatch species. The position of the beautiful nuthatch within the genus was not established with certainty, having a far lower statistical association than others in the model. Nevertheless, under the findings the species appears closest evolutionarily to three clades of nuthatches: two nuthatches that prefer rocky environments, the western rock nuthatch (''S. neumayer'') and the eastern rock nuthatch (''S. tephronota''); species in the "europaea" group, including the Eurasian nuthatch (''S. europaea''), Siberian nuthatch (''S. arctica''), chestnut-vented nuthatch (''S. nagaensis''), Kashmir nuthatch (''S. cashmirensis''), Indian nuthatch (''S. castanea''), chestnut-bellied nuthatch (''S. cinnamoventris'') and the Burmese nuthatch (''S. neglecta''); as well as the white-tailed nuthatch (''S. himalayensis''), and therefore, the white-browed nuthatch (''S. victoriae''). These close relatives are generally all species that plaster the entrance to their nest with mud.〔 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「Beautiful nuthatch」の詳細全文を読む スポンサード リンク
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