Tachycineta (Greek: tachýs "fast", kīnéō "move") is a genus of birds in the swallow family. There are nine described species. Its members are restricted to the Americas. These are slender swallows with forked tails. Most species have a metallic green back, green or blue head, and metallic blue or unglossed brown wings. All have pure white underparts, and four species have a white rump. Tachycineta swallows are mostly at least partially migratory, with only golden and mangrove swallow being essentially resident. All the species use natural or disused cavities for nest sites.