Stocky martin with broad (but pointed) wings, broad tail and broad head. Mostly dusky brown with paler underparts, except almost black under wing-coverts, and fairly dark vent. Most tail-feathers with small, white "window" visible from below. Immature similar to adults, but with pale fringes to coverts. Flight less acrobatic than other martins, with frequent, long glides. Strays less away from breeding grounds than congeners.
Sound:Most heard is a House Martin-like, but less rolling, "prit" or "check". Other contact sounds include a plaintive "peeuuu". Song an inconspicuous, staccato series of twittering notes, with a wagtail-like timbre.
Calls, song:
Distribution:
Wikipedia: map (se also Xeno-canto below)
Ecology:Birdlife ecology
Links:Observation.org Latest observations
Image search Flickr NB! May give other species
CC