White-rumped Swift

The white-rumped swift (Apus caffer) is 14–15.5 cm long and has a short forked tail and long swept-back wings that resemble a crescent or a boomerang. It is entirely dark except for a pale throat patch and a narrow white rump. It is similar to the closely related little swift, but is slimmer, darker and has a more forked tail and a narrower white rump. This is a quiet species compared to little swift, but a twittering trill is sometimes given.