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The crag martins are four species of small passerine birds in the genus ''Ptyonoprogne'' of the swallow family. They are the Eurasian crag martin (''P. rupestris''), the pale crag martin (''P. obsoleta''), the rock martin (''P. fuligula'') and the dusky crag martin (''P. concolor''). They are closely related to each other, and have formerly sometimes been considered to be one species. They are closely related to the ''Hirundo'' barn swallows and are placed in that genus by some authorities. These are small swallows with brown upperparts, paler underparts without a breast band, and a square tail with white patches. They can be distinguished from each other on size, the colour shade of the upperparts and underparts, and minor plumage details like throat colour. They resemble the sand martin, but are darker below, and lack a breast band. These are species of craggy mountainous habitats, although all three will also frequent human habitation. The African rock martin and the south Asian dusky crag martin are resident, but the Eurasian crag martin is a partial migrant; birds breeding in southern Europe are largely resident, but some northern breeders and most Asian birds are migratory, wintering in north Africa or India. They do not normally form large breeding colonies, but are more gregarious outside the breeding season. These martins build neat mud nests under cliff overhangs or in crevices in their mountain homes, and have readily adapted to the artificial cliffs provided by buildings and motorway bridges. Up to five eggs, white with dark blotches at the wider end, may be laid, and a second clutch is common. ''Ptyonoprogne'' martins feed mainly on insects caught in flight, and patrol cliffs near the breeding site with a slow hunting flight as they seek their prey. They may be hunted by falcons and infected with mites and fleas, but their large ranges and populations mean that none of the crag martins are considered to be threatened, and all are classed as Least Concern on the IUCN Red List. == Taxonomy == The four ''Ptyonoprogne'' species are the Eurasian crag martin (''P. rupestris'') described as ''Hirundo rupestris'' by Italian naturalist Giovanni Antonio Scopoli in 1769, the pale crag martin (''P. obsoleta''), described by Jean Cabanis in 1850, the rock martin (''P. fuligula''), described by German zoologist Martin Lichtenstein in 1842, and the dusky crag martin (''P. concolor'') formally described in 1832 as ''Hirundo concolor '' by British soldier and ornithologist William Henry Sykes. They were moved to the new genus ''Ptyonoprogne'' by German ornithologist Heinrich Gustav Reichenbach in 1850.〔Reichenbach (1850) plate LXXXVII figure 6.〕 The genus name is derived from the Greek ''ptuon'' (φτυον), "a fan", referring to the shape of the opened tail, and Procne (Πρόκνη), a mythological girl who was turned into a swallow. These are members of the swallow family of birds, and are placed in the Hirundininae subfamily which comprises all swallows and martins except the very distinctive river martins. DNA sequence studies suggest that there are three major groupings within the Hirundininae, broadly correlating with the type of nest built. The groups are the "core martins" including burrowing species like the sand martin, the "nest-adopters", which are birds like the tree swallow that utilise natural cavities, and the "mud nest builders". ''Ptyonoprogne'' species construct a mud nest and therefore belong to the latter group; They resemble the ''Hirundo'' species in that they make open cup nests, whereas ''Delichon'' martins build closed cups, and the ''Cecropis'' and ''Petrochelidon'' swallows, have retort-like closed nests with an entrance tunnel. The genus ''Ptyonoprogne'' is closely related to the larger swallow genus ''Hirundo'' into which it is often subsumed, but a DNA analysis showed that a coherent enlarged ''Hirundo'' genus should contain ''all'' the mud-builder genera. Although the nests of the ''Ptyonoprogne'' crag martins resembles those of typical ''Hirundo'' species like the barn swallow, the DNA research showed that if the ''Delichon'' house martins are considered to be a separate genus, as is normally the case, ''Cecropis'', ''Petrochelidon'' and ''Ptyonoprogne'' should also be split off.〔 The small, pale northern subspecies of crag martin found in the mountains of North Africa and the Arabian peninsula is now usually split as the pale crag martin, ''Ptyonoprogne obsoleta''.〔 The remaining birds are now identified as Eurasian crag martin. 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「Crag martin」の詳細全文を読む スポンサード リンク
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