Fairly common to common summer migrant from winter grounds in Africa. Breeds colonially under eaves of buildings, where builds mud nests; feeds over varied open and semiopen habitats, especially water bodies and adjacent fields. Distinctive plumage, with blue-black upperparts, big white rump patch, and white underparts; tail fork shallower than on Barn Swallow, and flight jerkier overall, less smooth and graceful. Juvenile in late summer–autumn is duller above, dingier below than adult.