Easily recognized by pale reddish rump, pale finely streaked throat and breast, and black squared-off undertail coverts and tail. Typically glides on stiff, flat wings, flight quite languid with shallow wingbeats. Juveniles paler, lack reddish tones; may resemble Common House-Martin but note deeply forked tail. Builds mud nests in mountains, sea cliffs and on buildings and other structures. Forages over open areas.