High Quality Content by WIKIPEDIA articles! The Eurasian Crag Martin or just Crag Martin (Ptyonoprogne rupestris) is a small passerine bird in the swallow family. It is about 14 cm (5.5 in) long with ash-brown upperparts and paler underparts, and a short, square tail that has distinctive white patches on most of its feathers. It breeds in the mountains of southern Europe, northwestern Africa and southern Asia. It can be confused with the other two species in its genus, but is larger than both, with brighter tail spots and different plumage tone. Many European birds are resident, but some northern populations and most Asian breeders are migratory, wintering in northern Africa, the Middle East or India.