Marsh Harrier

Reedbed specialist

The marsh harrier is the only British bird of prey that is both a reedbed specialist and a ground nester — it builds its nest in dense reed or sedge, invisible from above. It hunts over the reedbed and surrounding wetland with the characteristic low, tilting flight of all harriers — wings held in a shallow V, gliding slowly over the vegetation and dropping suddenly onto prey. Its prey includes water birds, ducks, frogs, small mammals, and large insects.

Near-extinction and recovery

By 1971, marsh harriers had been reduced to a single breeding pair in Britain — at Minsmere in Suffolk — following decades of persecution, drainage of wetlands, and the effects of organochlorine pesticides (which caused eggshell thinning). This was one of the lowest points ever recorded for any British breeding bird. With legal protection, banning of DDT, and reedbed conservation, the population has grown to over 600 pairs today — one of conservation’s most notable raptor recoveries.

Male sky-dance

The male marsh harrier performs a spectacular aerial display in spring — a rollercoaster of steep climbs and plunging dives over the reedbed, rising and falling repeatedly. During the breeding season he performs “food passes”: carrying prey to the female, who rolls onto her back in flight to catch it with her talons as it is dropped. These sky passes are dramatic to observe.

Polygyny

Male marsh harriers frequently mate with two or three females whose territories overlap. Each female builds her own nest and raises her brood largely independently, though the male brings food to all of them. This polygynous mating system is unusual among British raptors.