Themarsh harriers arebirds of prey of theharrier subfamily. They are medium-sizedraptors and the largest and broadest-winged harriers. Most of them are associated with marshland and dense reedbeds. They are found almost worldwide, excluding only theAmericas.
Until recently two species were generally recognized: the marsh harrier (Circus aeruginosus) and theAfrican marsh harrier (C. ranivorus). The marsh harrier is now usually split into several species, sometimes as many as six. These are thewestern marsh harrier (C. aeruginosus),eastern marsh harrier (C. spilonotus),Papuan harrier (C. spilonotus spilothorax orC. spilothorax),swamp harrier (C. approximans),Réunion harrier (C. maillardi maillardi orC. maillardi) andMadagascar marsh harrier (C. maillardi macrosceles orC. macrosceles).
At the beginning of the 20th century, the marsh harrier was hunted to extinction in theUnited Kingdom.[1] After being reintroduced from other regions, its population steadily increased untilDDT threatened it, along with other raptors, in the 1950s and 1960s. Since, the population has slowly and steadily increased.
Thewestern marsh harrier (Circus aeruginosus), often simply called themarsh harrier, breeds widely acrossEurope andAsia. It is migratory except in the mildest regions, and winters mainly inAfrica. It hunts smallmammals,frogs,fish,insects andbirds, surprising them as it drifts low over fields and reedbeds. Its long legs allow it to pluck frogs and fish from the water mid-swoop.The western marsh harrier is a typical harrier, with long wings held in a shallow V in its low flight. It also resembles other harriers in having distinct male and female plumages, but its plumages are quite different from those of its relatives. The male has wings with grey and brown sections and black wingtips. Its head, tail and underparts are greyish, except for the chestnut belly. The female is mainly brown with a cream crown and cream leading edge to her wings. It is 19–22 inches long and weighs 1–2 lbs.[1]
Theeastern marsh harrier (C. spilonotus) breeds in the grasslands and wetlands of southernSiberia, northernMongolia, north-eastChina,Manchuria andJapan, andmigrates for the northern winter toSouth-east Asia, thePhilippines and northernBorneo.
Like all marsh harriers, it favours open, wet environments, and is frequently seen drifting low over rice fields, interspersing long, watchful circling glides with two or three slow, powerful wingbeats. Two subspecies are recognised:C. s. spilonotus of east Asia, andC. s. spilothorax, ofNew Guinea and the islands nearby, which is sometimes thought to be a separate species and is often called thePapuan harrier.
Theswamp harrier (C. approximans) at about 50 to 58 cm is slightly larger thanC. spilonotus, often a little darker, and has less heavily barred wings and tail. It is commonly found in suitable habitat anywhere inAustralasia, particularly in the higher rainfall areas to the east, south-east, and south-west, ofAustralia and throughoutNew Zealand, but also in the tropical north of Australia and the island groups ofNew Caledonia,Vanuatu,Fiji,Tonga and theSociety Islands. It is also known as theAustralasian harrier orPacific marsh harrier.
TheMadagascar marsh harrier orMadagascar harrier (C. maillardi) is found on theIndian Ocean islands ofMadagascar,Réunion and theComoros. It is sometimes split into two species: Madagascar harrier (Circus macrosceles) andRéunion harrier (C. maillardi).
TheAfrican marsh harrier (C. ranivorus) is a distinct non-migratory species that has not usually been included as a subspecies ofC. aeruginosus. It inhabits southern and easternAfrica.
