A large, slender falcon with long wings that nearly reach its tail tip when perched. It has a rusty crown above a thin white brow that can connect to its pale forecrown, above a bold dark eye-stripe that extends to the nape. The moustachial stripe sometimes seems to have a break at the gape line. Upperparts mostly brown; white underparts can be streaked at the breast and solid brown at the thighs. A species of open, arid country that preys mainly on birds.