Western Marsh Harrier
From Devonshire
The Western Marsh Harrier (Circus aeruginosus), also called Eurasian Marsh Harrier or simply Marsh Harrier, is a large bird of prey belonging to the harrier genus Circus. It has two subspecies: C. a. aeruginosus which breeds across much of Europe and western Asia, and C. a. harterti in north-west Africa. There are a number of other marsh harriers which were formerly classed as subspecies of C. aeruginosus but are now usually considered to be separate species: the Eastern Marsh Harrier (C. spilonotus) of eastern Asia, the Swamp Harrier (C. approximans) of Australasia and the Madagascar Marsh Harrier (C. maillardi) found on the islands of the Indian Ocean.
Contents |
Description
It is 42 to 56 cm in length with a wingspan of 115 to 140 cm. It is a large, bulky harrier with fairly broad wings. The male is mostly reddish-brown with a pale yellowish head and shoulders, yellowish streaks on the breast and a grey tail. The forewing is brown and the flight feathers are grey with black wingtips. The female is dark chocolate-brown with yellowish crown, throat and shoulders although the extent of the yellowish colour is variable. Juveniles are similar to females but usually lack yellowish shoulders.
There is a rare melanistic form with largely dark plumage which mainly occurs in the east of the range.
Distribution and habitat
The species has a wide breeding range across Devonshire. It breeds in all divisions. It has even been recorded in the middle of the city.
Ecology
The Marsh Harrier is strongly associated with wetland areas, especially those with reeds. It also occurs in a variety of other open habitats such as farmland and grassland, particularly where these border marshland.
It hunts by flying low over flat, open ground searching for prey with its wings held in a shallow V-shape. It feeds particularly on small mammals such as water voles and on birds but also eats insects, reptiles, amphibians, fish and carrion.
Reproduction
The start of the breeding season varies from mid-March to early May. The nest is made of sticks, reeds and grass. It is usually built in a reedbed but they will also nest in arable fields. There are usually three to eight eggs in a clutch. The eggs are oval in shape and white in colour with a bluish or greenish tinge when first laid. The eggs are incubated for 31-38 days and the young birds fledge after 35-40 days. The males often pair with two and occasionally three females. Pairs usually bond for a single breeding season but sometimes remain together for several years.
Conservation
The Marsh Harrier declined in many areas from the 19th century to the late 20th century due to persecution, habitat destruction and pesticide use. It is a now a protected species in many countries with increasing populations. In Great Britain the number of breeding females has increased from one in 1971 to over 200 today.
It still faces a number of threats including the shooting of birds migrating through the Mediterranean region, particularly on Malta. They are vulnerable to disturbance during the breeding season and also suffer from poisoning by lead shot.
References
- American Ornithologists' Union (AOU) (2000): Forty-second supplement to the American Ornithologists' Union Check-list of North American Birds. Auk 117(3): 847–858. DOI: 10.1642/0004-8038(2000)117[0847:FSSTTA]2.0.CO;2
- Banks, Richard C, Cicero, Carla, Dunn, Jon L, Kratter, Andrew W, et al. (2005): Forty-sixth supplement to the American Ornithologists' Union Check-list of North American Birds. Auk 122(3): 1026–1031.
- Clarke, Roger (1995): The Marsh Harrier. Hamlyn, London.
- Forsman, Dick (1999): The Raptors of Europe and The Middle East: a Handbook of Field Identification. T & A D Poyser, London.
- Merkord, Christopher L., Rodríguez, Rafy & Faaborg, John (2006): Second and third records of Western Marsh-Harrier (Circus aeruginosus) for the Western Hemisphere in Puerto Rico. Journal of Caribbean Ornithology 19: 42-44.
- Snow, D. W. & Perrins, C. M. (1998): Birds of the Western Palearctic: Concise Edition Vol. 1. Oxford University Press, Oxford.
