The eastern marsh harrier (''Circus spilonotus'') is a

bird of prey Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...

belonging to the

marsh harrier The marsh harriers are bird of prey, birds of prey of the harrier (bird), harrier subfamily. They are medium-sized Bird of prey, raptors and the largest and broadest-winged harriers. Most of them are associated with marshland and dense reedbeds. ...

group of harriers. It was previously considered to be

conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organism ...

with the

western marsh harrier The western marsh harrier (''Circus aeruginosus'') is a large harrier (bird), harrier, a bird of prey from temperate and subtropical western Palearctic, Eurasia and adjacent Africa. It is also known as the Eurasian marsh harrier. Formerly, a numb ...

(''Circus aeruginosus'') but is now usually classified as a separate species. It has two

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

: ''C. s. spilonotus'' in eastern

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

and ''C. s. spilothorax'' (

Papuan harrier The Papuan harrier (''Circus spilothorax'') is a bird of prey native to New Guinea which belongs to the harrier genus ''Circus''. It was classified as a subspecies of the eastern marsh harrier (''Circus spilonotus'') of eastern Asia. It is thi ...

, perhaps a separate species) in

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

Description

It is 48 to 58 cm long with a wingspan of 113 to 137 cm; like most birds of prey, the female is usually larger than the male. The male's

plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...

is variable; typically the head, breast, back and wing-coverts are blackish with pale streaks. The rest of the wing is grey with black wingtips and a white front edge. The tail is grey, the rump is white and the underparts are mostly white. The female is dark brown with buff streaking on the head and underparts. The rump is often whitish and the tail has dark bars. Young birds are dark brown with buff on the head and a pale patch on the underwing. It is usually silent but has a mewing call which is most often uttered at roost sites.

Distribution and habitat

Eastern marsh harriers are generally migratory apart from the Papuan harrier which is sedentary. The breeding range covers north-east China,

Mongolia Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...

and south-east

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

(as far west as

Lake Baikal Lake Baikal is a rift lake and the deepest lake in the world. It is situated in southern Siberia, Russia between the Federal subjects of Russia, federal subjects of Irkutsk Oblast, Irkutsk Oblasts of Russia, Oblast to the northwest and the Repu ...

) with small numbers in northern

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

(

Hokkaidō is the second-largest island of Japan and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by railway via the Seikan Tunnel. The ...

and northern

Honshū , historically known as , is the largest of the four main islands of Japan. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the seventh-largest island in the world, and the second-most populous after the Indonesian ...

). There is some overlap with western marsh harrier around Lake Baikal and

interbreeding In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, subspecies, species or genera through sexual reproduction. Generally, it means that each cell has genetic material from two di ...

has taken place. The wintering range includes southern China,

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

Korea Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in 1945, it has been politically Division of Korea, divided at or near the 38th parallel north, 3 ...

, southern Japan,

northeast India Northeast India, officially the North Eastern Region (NER), is the easternmost region of India representing both a geographic and political Administrative divisions of India, administrative division of the country. It comprises eight States and ...

Bangladesh Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia. It is the List of countries and dependencies by population, eighth-most populous country in the world and among the List of countries and dependencies by ...

and Southeast Asia as far south as the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

and

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

. Large numbers of birds migrate along the Chinese coast with thousands passing through sites like Beidaihe during the autumn. Its preferred habitat is open country including

marshland In ecology, a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p More in general ...

, paddy fields and

grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...

Diet and reproduction

While hunting it flies low over the ground with the wings held in a shallow V-shape. Its prey includes small mammals, birds and frogs. The

breeding season Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and ch ...

begins in April. The nest is made of sticks and built on the ground, usually in a

reedbed A reedbed or reed bed is a natural habitat found in floodplains, waterlogged depressions and estuaries. Reedbeds are part of a succession from young reeds colonising open water or wet ground through a gradation of increasingly dry ground. As ...

. Four to seven eggs are laid which are incubated for 33 to 48 days. The young birds

fledge Fledging is the stage in a flying animal's life between egg, hatching or birth and becoming capable of flight. This term is most frequently applied to birds, but is also used for bats. For altricial birds, those that spend more time in vulnera ...

after 35 to 40 days.

References

*Mark A. Brazil (1991) ''The Birds of Japan'', Christopher Helm, London *Roger Clarke (1995) ''The Marsh Harrier'', Hamlyn, London. *John MacKinnon & Karen Phillipps (2000) ''A Field Guide to the Birds of China''. Oxford University Press. *Craig Robson (2002) ''A Field Guide to the Birds of South-East Asia''. New Holland, London. {{Authority control eastern marsh harrier Birds of prey of Asia Birds of Manchuria Birds of Mongolia eastern marsh harrier