Western Marsh-Harrier

Western Marsh-Harrier


Profile Western Marsh-Harrier     Literature page Western

[order] Falconiformes | [family] Accipitridae | [latin] Circus aeruginosus | [UK] Western Marsh-Harrier | [FR] Busard des roseaux | [DE] Rohrweihe | [ES] Aguilucho Lagunero Occidental | [IT] Falco di palude | [NL] Bruine Kiekendief

Bruine Kiekendief determination

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Plumage variable. Male generally brown above particularly on back, underparts streaked, but solid dark brown at least on belly and vent. plumage becomes progressively paler with age.
Female averages larger, usually brown with yellowish cream crown, throat and forewing.
All dark or melanistic morph in some adults. Race harterti has much paler underparts than nominate.

This species is a bird of swamps, marshes, flood plains or rice fields and reed beds. On migration it is much less likely to be seen in dry open grassland than other harriers and principally follows river valleys or coasts, though it must cross dry areas sometimes. ln its winter quarters it is often very common, e.g. in rice fields in South India.

This harrier inhabits open swamps in northern Africa and Eurasia, between 30°N and 62°N. The birds of the south and south-west are largely sedentary, but those from the north and the north-east are mainly wintering in sub-Saharan Africa. About 10000 breeding pairs inhabit the European Union. Some populations have definitely increased in western Europe, but those of the southern part of the continent are steadily decreasing, e.g. in the Iberian Peninsula

Being a good bit bigger than the Hen Harrier, the Marsh Harrier can take a wider variety of prey. During the breeding season his hunting area is reduced and it must take advantage of local abundances. At that time he concentrates on marsh birds and small mammals which are easily caught, relying on surprise rather than speed. The Harrier generally quarters flat areas at a height of only a few meters, always taking advantage of cover, sometimes hovering or performing impressive aerobatics before dropping with claws outstretched. Prey is sometimes spotted from a low perch.
Birds taken include poultry, ducks, waders, coot, moorhen, water rail, gulls, young pheasants and partridges, and songbirds and their young. Mammals include voles, mice, rabbits, moles, rats and young hares. Frogs are also important.

This species has an estimated global Extent of Occurrence of 1,000,000-10,000,000 km2. It has a large global population estimated to be 100,000-1,000,000 individuals (Ferguson-Lees et al. 2001). Global population trends have not been quantified, but populations appear to be stable (Ferguson-Lees et al. 2001) so the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]

During courtship the male carries out spectacular aerobatics over the nest and surrounding area. He soars in high circles, sometimes flying with exaggerated wing beats, and occasionally calling. Sometimes the pair display together, when he dives down at her and she rolls over to present her talons.
The nest is well hidden in the dense reed bed or other thick vegetation in shallow water. The female takes about 10 days to build the pile of sticks, reeds and grass that serves as a nest. Meanwhile, the male makes a platform for resting and feeding. Both parents add material to the main nest during fledging.
The female incubates for 31-38 days per egg, usually starting with the first. The male provides for the female near the nest.
For the first week or so the chicks are brooded by the female, who feeds them beak-to-beak, but later they feed themselves in the nest, often with some ferocity, especially if the female is not very attentive. During lean times the bigger chicks may kill and eat their smaller siblings. The male brings food in the typical harrier way, dropping it for the female to catch in the air. As the young develop, the female helps with the hunting. She can rear the brood on her own if her mate is killed or deserts her. After a month or so the chicks scatter into the surrounding vegetation. They fledge at 35-40 days. The male soon leaves after that, but they usually remain with the female for a further 15-25 days.

Mainly migratory in Northern & Eastern Europe and Central Asia; sedentary and dispersive in South of breeding range. Northern breeders winter from France and North Africa through Mediterranean to Turkey, Middle East and Nile Valley, and South to sub-Saharan Africa. Easternmost Asian populations winter in Indian Subcontinent and Sri Lanka.
Migration in Western Europe begins with young birds of the year in mid-August, followed by adults in September and October. Males migrate later than females and young, and arrive in wintering grounds later.
The rate and extent of migration varies according to the place of origin, northern birds leaving earlier, moving faster and travelling further than do birds from Southern Europe, which may remain most of the winter quite close to their breeding areas. The southern migration from Europe follows well-marked routes through Gibraltar or the Bosphorus, and rarely crosses large bodies of water; they may reach high altitudes up to 9,000 feet when crossing mountain passes on migration, but usually favour low ground.
Northward migration begins again in February and March, and both at this time and in autumn they are more gregarious than usual, roosting communally in swamps like some other harriers, with up to 300 together in some races. The northward migration frequently crosses the Mediterranean, so that evidently they can cross large bodies of water if necessary. Returning birds arrive in their breeding haunts from late March onwards, as late as early May in the northern parts of the range. They generally migrate singly or in small parties, not in large flocks, but often roost gregariously even when hunting singly. In winter quarters the same individuals may frequent the same area for weeks at a time.


  1. Measurements
  2. spanwidth min.: 115 cm
  3. spanwidth max.: 140 cm
  4. size min.: 43 cm
  5. size max.: 55 cm
  6. Breeding
  7. incubation min.: 31 days
  8. incubation max.: 38 days
  9. fledging min.: 30 days
  10. fledging max.: 40 days
  11. broods 1
  12. eggs min.: 3
  13. eggs max.: 8
  14. Conservation Status
  15. Bruine Kiekendief status Least Concern
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