Dusky crag martin

The dusky crag martin was formally described by in 1832 as Hirundo concolor by British soldier and ornithologist William Henry Sykes.[2] It was moved to the new genus Ptyonoprogne by German ornithologist Heinrich Gustav Reichenbach in 1850.[3] Its nearest relatives are the three other members of the genus, the rock martin P. fuligula, the pale crag martin, P. obsoleta, and the Eurasian crag martin P. rupestris.[4] The genus name is derived from the Greek ptuon (πτύον), "a fan", referring to the shape of the opened tail, and Procne (Πρόκνη), a mythological girl who was turned into a swallow.[5] The specific concolor is from Latin, con "together", and color "colour" and refers to the bird's uniform colouration.

The four Ptyonoprogne species are members of the swallow family of birds, and are classed as members of the subfamily Hirundininae which comprises all swallows and martins except the very distinctive river martins. DNA studies suggest that there are three major groupings within the Hirundininae, broadly correlating with the type of nest built.[6] 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". The Ptyonoprogne species construct an open mud nest 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.[7]

The genus Ptyonoprogne is closely related to the larger swallow genus Hirundo into which it is often subsumed, but a DNA analysis showed that an enlarged Hirundo should contain all the mud-builder genera, including the Delichon house martins, a practice which few authorities follow. Although the nests of the Ptyonoprogne crag martins resemble those of typical Hirundo species like the barn swallow, the research showed that if Delichon, Cecropis and Petrochelidon are split from Hirundo, Ptyonoprogne should also be considered as a separate genus.[6]

In Pakistan, the breeding range of the dusky crag martin overlaps that of the subspecies P. f. peloplasta of pale crag martin, but that species breeds much higher in the mountains. This altitudinal separation means that it is not known whether the two closely related martins could hybridise, which would cast doubts as to whether they were distinct species.[8] Dusky crag martins from Burma and Thailand have been described as a separate darker subspecies, P. c. sintaungensis (originally Krimnochelidon concolor sintaungensis, Baker, 1832),[9] but it is not clear that the difference is greater than that between individual martins of the nominate subspecies.[8][10]

The dusky crag martin is 13 cm (5 in) long with a broad body, wings and tail. It has sooty-brown upperparts and slightly paler underparts, with a streaked pale dull rufous chin, throat and foreneck. The tail is short and square, with small white patches near the tips of all but the central and outermost pairs of feathers. The underwing coverts are dark brown, the eyes are brown, the small bill is mainly black, and the legs are brownish-pink. The sexes are alike, but juveniles have rufous grey tips to the plumage of the upperparts and wings. This species can be distinguished from the Eurasian crag martin and rock martin by its darker underparts,[8] and its white tail spots are significantly smaller than those of the Eurasian crag martin.[11] The under-tail coverts are of the same shade as the underside of the abdomen but these are darker in the Eurasian crag martin.[12]

This small martin's flight is typically slow and leisurely, but it is capable of considerable speed when required.[13] The calls are similar to those of the Eurasian crag martin and include a soft chi, chi contact call and a twittering song.[8]

The nominate subspecies of the dusky crag martin breeds in much of the Indian subcontinent from the base of the Himalayas south to the Nilgiri mountains and east to West Bengal,[13] and P. c. sintaungensis is found in southwestern China, and the northern parts of Thailand, Vietnam and Laos. The dusky crag martin is largely resident apart from local movements after breeding, but it has bred in Malaysia at least once, and occurred as a vagrant to Sri Lanka and probably Borneo.[1][8]

The natural breeding habitat is hilly or mountainous country with cliffs, gorges and caves, with nesting typically up to an altitude of about 1,800 m (5,900 ft), although up to 2,000 m (6,600 ft) in Thailand.[14] This martin also breeds in lowland areas utilising man-made structures as a substitute for natural precipices. Stone buildings such as old forts are particularly favoured, and the dusky crag martin can be found in urban areas including Mumbai.[1][8] Nests on buildings can be 30 m (98 ft) from the ground,[15] and include unusual sites such as light fittings.[16]

In addition to predation by birds of prey such as the peregrine falcon, this small martin has been recorded in the diet of the greater false vampire bat, Megaderma lyra.[20]

The total population of the dusky crag martin has not been quantified, but it is suspected to be increasing owing to the availability of artificial nest sites.[1] This martin is locally common in India, Thailand, and southern China,[8][21] and there appear to be range extensions to the northeast into Guangxi,[22] southwards into lowland Laos,[23] and westwards to the hills and plains of Sindh.[24] There is also a recent unconfirmed report from Cambodia.[25] Its large range and presumed high numbers mean that the dusky crag martin is not considered to be threatened, and it is classed as Least Concern on the IUCN Red List.[1]

• Ali, Salim; Ripley, Sidney Dillon (1986). Handbook of the birds of India and Pakistan. Vol. 5 (2nd ed.). Oxford University Press. ISBN 0-19-561857-2.
• Baker, E C S (1926). Fauna of British India. Birds. Vol. 3 (2nd ed.). Taylor and Francis, London.
• Hume, Allan Octavian (1890). The nests and eggs of Indian birds. Vol. 2 (2nd ed.). R H Porter, London.
• Lekagul, Boonsong; Round, Philip (1991). A Guide to the Birds of Thailand. Saha Karn Baet. ISBN 974-85673-6-2.
• Rasmussen P C; Anderton, J C (2005). Birds of South Asia: The Ripley Guide. Vol. 2. Smithsonian Institution & Lynx Edicions. ISBN 84-87334-66-0.
• Reichenbach, Heinrich Gustav (1850). Avium systema naturale (in German). Dresden and Leipzig: F. Hofmeister.
• Robson, Craig (2004). A Field Guide to the Birds of Thailand. New Holland Press. ISBN 1-84330-921-1.
• Turner, Angela K; Rose, Chris (1989). A handbook to the swallows and martins of the world. Christopher Helm. ISBN 0-7470-3202-5.

• Vyawahare, P M (1992) "Nest construction technique of Dusky Crag Martin Hirundo concolor with a note on its incubation period" Pavo 30(1&2):67–74.