Brightly-colored swallow with a deeply forked tail, pale orangish rump, black squared-off undertail coverts, and an incomplete orange collar. Varies significantly across range: European and African birds have clean whitish or orangish underparts, while Asian birds are extensively streaked below; compare carefully with other Cecropis swallow species where range overlaps occur. Juveniles average paler and lack extensive orangish tones; may resemble house-martins but note deeply forked tail. Typically glides on stiff, flat wings, flying quite languidly with shallow wingbeats. Builds mud nests in mountains, sea cliffs and on buildings and other structures. Forages over open areas. Frequently gives a short, sparrow-like “twi’wit.”