The Hen Harrier (Circus cyaneus) is a slim raptor that glides low over open ground on wings held in a shallow V — the male's pale blue-grey plumage and the female's striking white rump make the species almost unmistakable. It measures 45–55 cm long, with a wingspan of 97–122 cm and a weight of 300–600 grams. The male is pale blue-grey above with a white underside and contrasting black wingtips, while females and young birds are brown with heavily streaked underparts and an eye-catching pure white rump — so distinctive that the female is colloquially nicknamed the "white-rumped hawk". Its wings are broader and less pointed than those of the slender Montagu's Harrier.
The Hen Harrier is mostly silent, though the male can be heard giving a rapid, light cackling "pii-pii-pii" during his display flight. It nests on the ground, well hidden in a bog, young forest or other dense low vegetation, with the female laying 4–6 eggs and incubating while the male hunts and provisions her — a vulnerable arrangement, since ground nests are exposed to disturbance and predators. It hunts by quartering low and slowly over open country before striking prey in a sudden turn, feeding mainly on voles and mice but also taking small birds, frogs and lizards; vole abundance strongly shapes breeding success from year to year. Breeding mainly in northern Sweden's bogs and clearcuts and more sparsely further south, with a population of roughly 500–1,500 pairs, the species has declined enough in Sweden to be red-listed even though it remains more secure elsewhere in its range.
Read about this species in Swedish →