ডবাশেন

ডবাশেন N.N. Dutta et al, Annals of Biological Research, 2011, 2 (5):374-384(, বৈজ্ঞানিক নাম-Circus aeruginosus) এটা ডাঙৰ আকাৰৰ মাংসভোজী চৰাইৰ প্ৰজাতি। ইয়াক সাধাৰণতে এছিয়া আৰু আফ্ৰিকা মহাদেশৰ প্ৰায়বোৰ অঞ্চলতে দেখা পোৱা যায়। 
বিৱৰণ

The Western Marsh-harrier is 43 to 54 cm in length, and has a wingspan of 115 to 130 cm and a weight of 400 to 650 g in males and 500 to 800 g in females. It is a large, bulky harrier with fairly broad wings, and has a strong and peculiar sexual dichromatism. The male's plumage is mostly a cryptic reddish-brown with lighter yellowish streaks, which are particularly prominent on the breast. The head and shoulders are mostly pale greyish-yellowish. Whether from the side or below, flying males appear characteristically three-colored brown-grey-black. The legs, feet, irides and the cere of the black bill are yellow.

The female is almost entirely chocolate-brown. The top of the head, the throat and the shoulders have of a conspicuously lighter yellowish colour; this can be clearly delimited and very contrasting, or (particularly in worn plumage) be more washed-out, resembling the male's head colors. But the eye area of the female is always darker, making the light eye stand out, while the male's head is altogether not very contrastingly colored and the female lacks the grey wing-patch and tail. Juveniles are similar to females, but usually have less yellow, particularly on the shoulders.

টেক্স'নমি
The Western Marsh-harrier is often divided into two subspecies, the widely migratory C. a. aeruginosus which is found across most of its range, and C. a. harterti which is resident all-year in north-west Africa.
বিতৰণ
 thumb | left | The Male is characterised by the very clear chestnut brown mantle and the grey secondaries and black outer primaries

This species has a wide breeding range from Europe and northwestern Africa to Central Asia and the northern parts of the Middle East. It 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 harterti inhabits Morocco, Algeria and Tunisia.

বাসস্থান
 thumb | left | The female usually is identifiable using the rather dark plumage except the creamy crown, nape and throat

Like the other marsh-harriers, it is strongly associated with wetland areas, especially those rich in Common Reed (Phragmites australis). It can also be met with in a variety of other open habitats, such as farmland and grassland, particularly where these border marshland. It is a territorial bird in the breeding season, and even in winter it seems less social than other harriers, which often gather in large flocksClarke et al. (1998)
আচৰণ
It hunts in typical harrier fashion, gliding low over flat open ground on its search for prey, with its wings held in a shallow V-shape and often with dangling legs.

খাদ্য
It feeds on small mammals, small birds, insects, reptiles, and frogs.http://www.rspb.org.uk/wildlife/birdguide/name/m/marshharrier/index.aspxhttp://www.bbc.co.uk/nature/life/Western_Marsh_Harrier

প্ৰজনন
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 ground nest is made of sticks, reeds and grasses. It is usually built in a reedbed, but the species will also nest in arable fields. There are between three and eight eggs in a normal clutch. The eggs are oval in shape and white in colour, with a bluish or greenish tinge when recently laid. The eggs are incubated for 31–38 days and the young birds fledge after 35–40 days.

স্থিতি তথা সংৰক্ষণ
The Western Marsh-harrier declined in many areas between the 19th and the late 20th centuries due to persecution, habitat destruction and excessive pesticide use. It is a now a protected species in many countries. Its numbers are rising again in many places, most notably perhaps in Great Britain, where a single breeding female was left in 1971, whereas today over 200 pairs are present.

It still faces a number of threats, including the shooting of birds migrating through the Mediterranean region. They are vulnerable to disturbance during the breeding season and also liable to lead shot poisoning. Still, the threats to this bird have been largely averted and it is today classified as Species of Least Concern by the IUCN.

তথ্যসূত্ৰ

লগতে চাওক
 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 PDF fulltext
 Banks, Richard C.; Cicero, Carla; Dunn, Jon L.; Kratter, Andrew W.; Rasmussen, Pamela C.; Remsen, J.V. Jr.; Rising, James D. & Stotz, Douglas F. (2005): Forty-sixth supplement to the American Ornithologists' Union Check-list of North American Birds. Auk 122(3): 1026–1031. DOI: 10.1642/0004-8038(2005)122[1026:FSTTAO]2.0.CO;2 PDF fulltext
 Clarke, R.; Prakash, V.; Clark, W.S.; Ramesh, N. & Scott, D. (1998): World record count of roosting harriers Circus in Blackbuck National Park, Velavadar, Gujarat, north-west India. Forktail 14: 70-71. PDF fulltext
 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(1): 42-44. PDF fulltext 
 Verma, Ashok (2002): A large roost of Eurasian Marsh Harriers Circus aeruginosus at Keoladeo National Park, Bharatpur, India. Forktail 18: 150-151. PDF fulltext
 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.
 Snow, David W. & Perrins, Christopher M. (eds.) (1998): The Birds of the Western Palearctic (Concise ed., Vol. 1). Oxford University Press. ISBN 0-19-854099-X

বাহ্যিক সংযোগ

RSPB - Marsh harrier
Birds of Britain - Marsh Harrier 
 (Western Marsh Harrier = ) European Marsh Harrier - Species text in The Atlas of Southern African Birds
Internet Bird Colloection Videos
Oiseaux Text, map, photos.
 Ageing and sexing (PDF; 5.7 MB) by Javier Blasco-Zumeta & Gerd-Michael Heinze

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