The Western Marsh Harrier (Circus aeruginosus) is the largest and most powerful of the harriers, measuring 43–55 cm with a wingspan of 115–140 cm and weighing 400–900 g. The male has a brown body, light grey wings with contrasting black wingtips, and a grey tail, while the female — larger than the male — is uniformly dark chocolate-brown with a striking creamy-yellow crown, throat and leading wing edge. Like other harriers it has long wings and a long tail, and flies with wings held in a shallow, characteristic V as it quarters slowly and low over the reeds.
Mostly silent, the male gives a bright, whining "kiu-kiu-kiu" during his spring display flight but is rarely heard away from the breeding site. It hunts by gliding low and watchfully over reedbeds, dropping suddenly onto prey, taking coots and other marsh birds, ducklings, small rodents, frogs, bird eggs and occasionally fish remains or carrion. The nest is a platform of reed and plant material built on the ground or amid wet reed, well concealed; the female lays 4–5 eggs and incubates them for 31–38 days while the male hunts and provisions her. Breeding mainly in southern and central Sweden around large, reed-rich lowland lakes such as Hornborgasjön, Tåkern, Kvismaren and Oset, the Swedish population of roughly 1,500–2,500 pairs has grown markedly since the species nearly disappeared during the pesticide era of the mid-20th century. It is a migrant, arriving in April and leaving in September to winter around the Mediterranean and in Africa.
Read about this species in Swedish →