Montagu's harriers are scarce summer visitors to southern Britain.
Montagu's harriers have a body length of 43-50cm, a wingspan of 97-115cm and weigh 0.2-0.4kg.
The females are brown with a white rump and are virtually indistinguishable from hen harriers. Juveniles are also brown but have reddish-brown under-parts. The males are pale grey with a black wing bar and wing tips, and a grey rump.
Montagu's harriers occupy NW Africa, Asia and warm/temperate regions of Europe and Russia.
They prefer open areas, such as meadows, grassland, cereal fields, heath, moor, scrubland, marshes and bogs.
Montagu's harriers feed on small ground birds (including chicks of their own species during the breeding season), small mammals (particularly voles), reptiles and invertebrates.
They hunt by flying slowly and low until they spot prey, whereupon they kill the victim on the ground. Montagu's harriers are migratory and winter in Africa and Asia.
Most egg-laying occurs from May to June. The nests are built on the ground in tall vegetation, and are made from grass and twigs. A clutch of 3-5 eggs are laid asynchronously, which the female incubates for 28 days. The chicks fledge after 30-40 days but are fed for a further two weeks. The males occasionally breed with and support two females.
Montagu's harriers are not considered to be globally threatened but their numbers are in decline. Due to their habit of nesting in cereal fields, many chicks are killed during harvesting and conservation groups try to protect the birds in Spain and France. In Britain there are only about a dozen pairs.
Their call is a shrill yick-yick-yick.