Small, fast-flying swift of humid tropical lowlands. Usually seen in pairs flying low over the forest canopy, but also ranges out over adjacent open areas, lakes, and rivers. Often in loose association with other small swifts, especially Vaux’s. Note the very narrow wings and long swallow tail, which is usually held closed in a long fine point rather than being spread to show the fork. The small size and bright white throat that contrasts with the black cap and body are distinctive.