Western Marsh Harrier

The Western Marsh Harrier (Circus aeruginosus), a bird of prey from temperate and subtropical western Eurasia and adjacent Africa, is a large harrier known for its impressive size and sexual dimorphism. Males typically exhibit a cryptic reddish-brown plumage with lighter streaks and a pale greyish-yellowish head and shoulders, while females are predominantly chocolate-brown with a lighter yellowish crown, nape, and throat.

Identification Tips

Males can be identified by their three-colored brown-grey-black appearance in flight, with grey rectrices and secondary and tertiary remiges contrasting with brown forewings and black primary remiges. Females have a darker eye area, making their light eyes stand out, and lack the grey wing-patch and tail seen in males. Juveniles resemble females but with less yellow, particularly on the shoulders.

Habitat

The Western Marsh Harrier is strongly associated with wetland areas, especially those rich in common reed (Phragmites australis). It can also be found in open habitats such as farmland and grassland, particularly where these border marshland.

Distribution

This species has a wide breeding range from Europe and northwestern Africa to Central Asia and the northern parts of the Middle East. It is migratory or dispersive, with some populations wintering in southern and western Europe, the Sahel, Nile basin, Great Lakes region in Africa, or in Arabia, the Indian subcontinent, and Myanmar.

Behaviour

The Western Marsh Harrier is a territorial bird during the breeding season and less social than other harriers in winter, likely due to habitat preferences. It hunts in typical harrier fashion, gliding low over open ground with wings held in a shallow V-shape.

Breeding

Breeding season varies, with males often pairing with multiple females. The ground nest is made of sticks, reeds, and grasses, usually in a reedbed. Clutches typically contain three to eight white eggs with a bluish or greenish tinge, incubated for 31–38 days.

Diet and Feeding

The Western Marsh Harrier feeds on small mammals, birds, insects, reptiles, and frogs, hunting by gliding low over the ground in search of prey.

Conservation Status

Once declining due to persecution, habitat destruction, and pesticide use, the Western Marsh Harrier is now protected and classified as Least Concern by the IUCN. It has made a comeback in areas like Great Britain and Ireland but still faces threats such as shooting during migration and disturbance during breeding.