Harriers are slow fliers and have the ability to remain airborne at speeds of less than 32 km/h (20 mph). Flying at such slow speeds makes it easier for them to detect prey.

Statistics
Marsh harriers have a body length of 48-56cm, a wingspan of 110-130cm and weigh 0.4-0.8kg.

Physical description
Males are brown with grey wings and tail, and there is less size difference between the sexes in this species than in other harriers. Juveniles and females also have brown plumage, but have pale heads and shoulder patches.

Distribution
This raptor is widespread across Europe, Asia and Africa.

Habitat
Their preferred habitat is moors, marshes, fens, reedbeds and swamps. Some species in Britain are now breeding in cereal fields.

Diet
Frogs make up a large component of the marsh harrier's diet, but they also feed on small mammals, reptiles, insects, eggs and nestlings.

Behaviour
Northern European and Asian birds tend to migrate, with British birds going to West Africa. But even in Britain, other birds are sedentary.

Reproduction
In April and May, the female builds a nest made from twigs and grass, generally in reed beds. The female incubates the clutch of 4-5 eggs, which hatch after about 36 days. The male brings the food although it is the female that feeds the chicks. After 38-40 days, the chicks leave the nest. Sometimes the males breed with more than one female.

Conservation status
Marsh harriers are not considered to be globally threatened, but numbers have declined over much of their range. However, their numbers are increasing in Britain.

Voice
Marsh harriers are not very vocal, but when alarmed, they have a chattering kekekeke call.