|
The white wagtail (''Motacilla alba'') is a small passerine bird in the wagtail family Motacillidae, which also includes the pipits and longclaws. This species breeds in much of Europe and Asia and parts of north Africa. It is resident in the mildest parts of its range, but otherwise migrates to Africa. It has a toehold in Alaska as a scarce breeder. In the British Isles the darker sub-species the pied wagtail (''M. a. yarrellii'') predominates. The white wagtail is an insectivorous bird of open country, often near habitation and water. It prefers bare areas for feeding, where it can see and pursue its prey. In urban areas it has adapted to foraging on paved areas such as car parks. It nests in crevices in stone walls and similar natural and man-made structures. The white wagtail is the national bird of Latvia.〔("National symbols of Latvia" ) 〕 ==Taxonomy and systematics== The white wagtail was one of the many species originally described by Linnaeus in his 18th-century work, ''Systema Naturae'', and it still bears its original name of ''Motacilla alba''. The Latin genus name originally meant "little mover", but certain medieval writers thought it meant "wag-tail", giving rise to a new Latin word ''cilla'' for "tail". The specific epithet ''alba'' is Latin for "white". Within the wagtail genus ''Motacilla'', the white wagtail's closest relatives appear to be other black-and-white wagtails such as the Japanese wagtail, ''Motacilla grandis'', and the white-browed wagtail, ''Motacilla madaraspatensis'' (and possibly the Mekong wagtail, ''Motacilla samveasnae'', the phylogenetic position of which is mysterious), with which it appears to form a superspecies. However, mtDNA cytochrome ''b'' and NADH dehydrogenase subunit 2 sequence data suggests that the white wagtail is itself polyphyletic or paraphyletic (i.e. the species is not itself a single coherent grouping). Other phylogenetic studies using mtDNA still suggest that there is considerable gene flow within the races and the resulting closeness makes ''Motacilla alba'' a single species. Some studies have suggested the existence of only two groups : the ''alboides'' group, with ''M. a. alboides'', ''M. a. leucopsis'' and ''M. a. personata''; and the ''alba'' group, with ''M. a. alba'', ''M. a. yarrellii'', ''M. a. baicalensis'', ''M. a. ocularis'', ''M. a. lugens'', and ''M. a. subpersonata''.〔Odeen, A. and Alstrom, P. (2001). Evolution of secondary traits in wagtails (genus Motacilla ). In: Odeen A. Effects of post-glacial range expansion and population bottlenecks on species richness. PhD. thesis, Uppsala University.〕 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「white wagtail」の詳細全文を読む スポンサード リンク
|