Tiny gray-and-white falcon that is similar in size to a shrike, though chunkier. The back is brown in females and gray in males. The white rump is conspicuous in fast, slightly undulating flight, which is very different from that of a typical falcon. Found in arid savanna, where it breeds in the nest of a Sociable Weaver or buffalo-weaver. Often perches up in the open, usually in pairs or small family groups. The call is a fast series of rasps or squeals.