The Nankeen Kestrel is a slender falcon and is a relatively small raptor. The upper parts are mostly rufous, with some dark streaking. The wings are tipped with black. The underparts are pale buff, streaked with black, and the under tail is finely barred with black, with a broader black band towards the tip. Females tend to be more heavily marked and have more rufous on the crown and tail. Males have a greyish crown and tail, although the extent varies between individuals. Hovers over grassland