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The pale crag martin (''Ptyonoprogne obsoleta'') is a small passerine bird in the swallow family that is resident in northern Africa and in southwestern Asia east to Pakistan. It breeds mainly in the mountains, but also at lower altitudes, especially in rocky areas and around towns. Unlike most swallows, it is often found far from water. It is 12–13 cm (4.7–5.1 in) long, with mainly brown plumage, paler-toned on the upper breast and underwing coverts, and with white "windows" on the spread tail in flight. The sexes are similar in appearance, but juveniles have pale fringes to the upperparts and flight feathers. It was formerly considered to be the northern subspecies of the rock martin of southern Africa, although it is smaller, paler, and whiter-throated than that species. The pale crag martin hunts along cliff faces for flying insects using a slow flight with much gliding. Its call is a soft twitter. This martin builds a deep bowl nest on a sheltered horizontal surface, or a neat quarter-sphere against a vertical rock face or wall. The nest is constructed with mud pellets and lined with grass or feathers, and may be built on natural sites under cliff overhangs or on man-made structures such as buildings and bridges. It is often reused for subsequent broods or in later years. This species is often a solitary breeder, but small groups may breed close together in suitable locations. The two or three eggs of a typical clutch are white with brown and grey blotches, and are incubated by both adults for 16–19 days prior to hatching. Both parents then feed the chicks. Fledging takes another 22–24 days, although the young birds will return to the nest to roost for a few days after the first flight. The pale crag martin is caught in flight by several fast, agile falcon species, such as hobbies, and it sometimes carries parasites, but it faces no major threats. Because of its range of nearly 6 million km2 (2.3 million sq mi) and a large and apparently increasing population, it is not seen as vulnerable and is assessed as Least Concern on the IUCN Red List. ==Taxonomy== The pale crag martin was first formally described in 1850 by German ornithologist Jean Cabanis as ''Cotyle obsoleta'', using a specimen collected from near Cairo, Egypt. It was moved to the new genus ''Ptyonoprogne'', created by German ornithologist Heinrich Gustav Reichenbach, in the same year.〔Reichenbach (1850) plate LXXXVII figure 6.〕 The genus name is derived from the Ancient 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. The specific name ''obsoleta'' means "worn" in Latin.〔Brookes (2003) p. 1031.〕 The ''Ptyonoprogne'' species are members of the swallow family of birds, and are classed as members of 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. These 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". The ''Ptyonoprogne'' species construct open mud nests and therefore belong to the last group. ''Hirundo'' species also build open nests, ''Delichon'' house martins have a closed nest, 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'', and is sometimes included within it since the nests of the ''Ptyonoprogne'' crag martins resemble those of typical ''Hirundo'' species like the barn swallow. However, a DNA analysis showed that if ''Hirundo'' is enlarged to contain the crag martins, it should include ''all'' the mud-builder genera. Conversely, 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 pale crag martin's nearest relatives are the other members of the genus, the dusky crag martin ''P. concolor'' of southern Asia, the rock martin ''P. fuligula'' of Southern Africa, and the Eurasian crag martin ''P. rupestris''.〔Turner & Rose (1989) pp. 158–164.〕 The pale crag martin was formerly often treated as the small, pale northern subspecies of the rock martin,〔〔 but it is now usually considered to be a separate species.〔 The changes in size and colour are continuous, so the evidence for separate species is not strong,〔 although some rock martins can weigh more than twice as much as the smallest subspecies of the pale crag martin. The average weight for ''P. o. fusciventris'' is 22.4 g (0.79 oz) against 10 g (0.35 oz) for ''P. o. obsoleta''.〔Dunning (1993) p. 327.〕 There do not appear to be any intermediate forms where pale crag martins and rock martin populations breed close to each other in Somalia and Ethiopia.〔Sibley & Monroe (1991) p. 576.〕 In areas of Pakistan where its range overlaps with that of the dusky crag martin, the pale crag martin breeds at a higher altitude.〔 Its range does not overlap there with the Eurasian crag martin, which is found high in the Himalayas, but where both occur in Iran, the pale crag martin favours more arid habitats.〔 In North Africa, the Eurasian species is again found at a higher level. The separation by altitude and aridity means that it is not known whether the closely related ''Ptyonoprogne'' martins could hybridise. If they were shown to do so, it would cast doubts on their specific distinctness.〔Turner & Rose (1989) pp. 163–164.〕 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「Pale crag martin」の詳細全文を読む スポンサード リンク
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