Description
These martins are 12–15 cm (4.7–5.9 in) long with drab brown or grey plumage and a short square tail that has small white patches near the tips of all but the central and outermost pairs of feathers. The eyes are brown, the small bill is mainly black, and the legs are brownish-pink. The sexes are similar, but juveniles show pale edges to the upperparts and flight feathers. The species differ in plumage shades and size, Eurasian Crag Martin being significantly larger than the others. The flight is slow, with rapid wing beats interspersed with flat-winged glides. The songs of these birds are simple twitterings, and contact calls include a high-pitched twee or chi, chi, and a tshir or trrt call like that of the House Martin.
These drab martins can only be confused with each other, or with sand martins of the genus Riparia. Even the smaller Ptyonoprogne species are slightly larger and more robust than the Sand Martin and Brown-throated Sand Martin, and have the white tail spots which are absent from the Riparia martins. Where the ranges of Ptyonoprogne species overlap, the Eurasian Crag Martin is darker, browner and 15% larger than the Rock Martin, and larger and paler, particularly on its underparts, than the Dusky Crag Martin. The white tail spots of the Eurasian Crag Martin are significantly larger than those of both its relatives. In the east of its range, the Rock Martin always has lighter, more contrasted underparts than the Dusky Crag Martin.
Read more about this topic: Crag Martin
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