The hen harrier (Circus cyaneus) is a slender, medium-sized hawk, with a long tail, wings and legs, a characteristic white rump, and a distinctive ‘facial disc’, which gives it an owl-like appearance. The male is grey above and white underneath, with obvious black wing-tips and contrasting yellow legs, eyes and facial skin. The female is larger and is quite different in appearance, being dark brown above, paler below, with dark streaks, and with bars on the wings and tail. Juvenile northern harriers resemble the female, but are usually darker above and more reddish-brown below, sometimes without streaking. The northern harrier uses a variety of calls, including a long, rapid series of kek notes, a piercing, descending scream, given by the female when soliciting food from the male, and a soft, chuckling call at the nest.