Prairie Falcons are slimmer and longer-tailed than Peregrine Falcons, and also more active, nervous and aggressive in behavior. Females are larger than males, but the sexes have similar plumages. Upperparts are a gray-brown, with light edges along many of the back feathers; the tail is brown with a white tip, and barring along the outer tail feathers. The throat and underparts are whitish with brown, elongated spots. The top and sides of the head are dark; the face has a light eyebrow, a white cheek, and a narrow brown mustache stripe. When seen in flight from below, dark triangles are visible on the inner portion of pale wings (“dirty armpits”) – a feature not seen on any other North American falcon. Prairie Falcons fly with shallow, stiff, powerful wingbeats, and soar on flat wings with the tail slightly fanned. These falcons often fly low and fast over the ground in pursuit of prey.