Western Marsh Harrier

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Image:WesternMarshHarrier.jpg

Common Name: Western Marsh Harrier
Scientific Name: Circus aeruginosus

Size: 17-21.2 inches (43 to 54 cm); Wingspan: 45-51 inches (115-130 cm)

Habitat: Eurasia and Africa; this species breeds in almost every country of Europe but is absent from mountainous regions and subarctic Scandinavia. It is rare but increasing in Great Britain where it has spread as far as eastern Scotland. In the Middle East, there are populations in Turkey, Iraq, and Iran, while in Central Asia the range extends eastwards as far as north-west China, Mongolia, and the Lake Baikal region of Siberia.

Most populations of the western marsh harrier are migratory or dispersive. Some birds winter in milder regions of southern and western Europe, while others migrate to the Sahel, Nile basin and Great Lakes region in Africa, or to Arabia, the Indian subcontinent, and Myanmar. The all-year resident subspecies C.a. harterti inhabits Morocco, Algeria, and Tunisia.

As the common name would suggest, marsh harriers are usually found in wetlands.

Status: Least Concern. Global population: 500,000 to 2,000,000 adult individuals. The species underwent a decline in numbers in the 18th and 19th centuries due to the effects of habitat drainage and persecution for predation upon game species. The population declined to just a single pair between 1959 and 1971, mainly as a result of egg-shell thinning caused by organochloride pesticides such as DDT. After 1972 the population began to recover. Current threats include the deliberate disturbance of nesting sites, egg collecting, illegal poisoning and predation by foxes. The small size of reed bed habitats may result in an increased impact of disturbance.

Diet: Small mammals and birds, carrion and sometimes insects, frogs and fish.

Hunting generally occurs over agricultural land or open habitat containing aquatic vegetation and at 2-6 m above ground. When prey is located the bird suddenly drops down with its talons outstretched.

Nesting: The plumage color is variable, but mainly brown. Females and immature individuals have creamy colored crowns and throats; mature males have dark brown bodies and wings, with the underside of the wings being pale-grey. Females are noticeably larger than males.

The start of the breeding season varies from mid-March to early May. Western marsh harrier males often pair with two and occasionally three females. Pair bonds usually last for a single breeding season, but some pairs remain together for several years. The courtship display involves the male flying in circles at a great height over the breeding area, then performing an elaborate sequence of tumbles as it falls toward the ground. Occasionally the female may join him, and the pair lock talons and tumble through the air together. As the season progresses the male may be seen dropping food into the female's talons in mid-air.

The female constructs the nest on the ground. It may measure up to 80 cm in diameter, and is made with grass, reeds and sticks. Three to eight eggs are laid. The eggs are incubated for 31–38 days and the young birds fledge after 35–40 days. Both parents contribute to the feeding of the chicks.

Cool Facts: There are records of marsh harriers in Britain that date from the Iron Age, about 3000 years ago. Excessive pesticide use dropped the population in Britain to extinction levels before pesticide banning and conservation measures were put in to place in 1972. The populations stabilized, and by 1994, there were 129 pairs. There are over 200 pairs today.

The western marsh harrier is divided into two subspecies:

  • C. a. aeruginosus, Widely migratory. It is found across most of its range.
  • C. a. harterti. A resident all-year in north-west Africa.


This 3D Model is found in Songbird ReMix Birds of Prey Volume II: Hawks of the Old World

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