The eastern marsh harrier (''Circus spilonotus'') is a bird of prey belonging to the

marsh harrier The marsh harriers are birds of prey of the harrier subfamily. They are medium-sized raptors and the largest and broadest-winged harriers. Most of them are associated with marshland and dense reedbeds. They are found almost worldwide, excluding o ...

group of harriers. It was previously considered to be conspecific with the western marsh harrier (''Circus aeruginosus'') but is now usually classified as a separate species. It has two

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

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

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

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 Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

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 ( "feather") 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, ...

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; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, ...

and south-east

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

(as far west as

Lake Baikal Lake Baikal (, russian: Oзеро Байкал, Ozero Baykal ); mn, Байгал нуур, Baigal nuur) is a rift lake in Russia. It is situated in southern Siberia, between the federal subjects of Irkutsk Oblast to the northwest and the Repu ...

) with small numbers in northern

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

(

Hokkaidō is Japan's second largest island 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 the undersea railway Seikan Tunnel. The la ...

and northern

Honshū , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island separa ...

). 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 breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in ...

has taken place. The wintering range includes southern China,

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

, southern Japan,

northeast India , native_name_lang = mni , settlement_type = , image_skyline = , image_alt = , image_caption = , motto = , image_map = Northeast india.png , ...

Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...

and Southeast Asia as far south as the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and eas ...

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 sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

. 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,

paddy field A paddy field is a flooded field (agriculture), field of arable land used for growing Aquatic plant, semiaquatic crops, most notably rice and taro. It originates from the Neolithic rice-farming cultures of the Yangtze River basin in sout ...

s and

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

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 cha ...

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 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 vulnerable c ...

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 The eastern marsh harrier (''Circus spilonotus'') is a bird of prey belonging to the marsh harrier group of harriers. It was previously considered to be conspecific with the western marsh harrier (''Circus aeruginosus'') but is now usually classi ...

Birds of prey of Asia Birds of Manchuria Birds of Mongolia