The western marsh harrier is a large harrier, a bird of prey from temperate and subtropical western Eurasia and adjacent Africa. It is also known as the Eurasian marsh harrier. Formerly, a number of relatives were included in C. aeruginosus, which was then known as "marsh harrier". The related taxa are now generally considered to be separate species: the eastern marsh harrier, the Papuan harrier of eastern Asia and the Wallacea, the swamp harrier of Australasia and the Madagascar marsh harrier of the western Indian Ocean islands.
Region
Western Palearctic
Typical Environment
Breeds across much of Europe and western Asia and winters in the Mediterranean basin, North Africa, the Middle East, and parts of sub-Saharan Africa. Strongly associated with freshwater and brackish wetlands, especially extensive reedbeds, marshes, and wet meadows. Also hunts over agricultural land, rice fields, and coastal lagoons when nearby marsh habitat is present. Uses migration flyways that follow major river valleys, coastlines, and wetland chains. Outside breeding, it can be widespread wherever suitable foraging habitat exists.
Altitude Range
Sea level to 1500 m
Climate Zone
Temperate
Ease of Keeping
Beginner friendly: 1/5
The western marsh harrier is a reedbed-nesting raptor that hunts with a low, buoyant quartering flight over wetlands and fields. Males and females look quite different, with males showing grey wings and black tips while females are darker with a creamy head. The species declined in parts of Europe due to persecution and pesticides but has rebounded following habitat protection and chemical bans. It plays a key role in controlling rodents and small bird populations around marshes.
A fairly pale adult female (note brown remiges and yellow eye) winters near Hodal (Faridabad district, Haryana, India)
Adult male (front), juvenile (behind) and adult female (back), illustration from 1899
The male is characterised by the very clear chestnut brown mantle and the grey secondaries and black outer primaries
The female usually is identifiable by the rather dark plumage except the creamy crown, nape, and throat
Egg, Collection Museum Wiesbaden, Germany
Wintering female hunting near Kolkata (West Bengal, India)
Western marsh harrier in Estonia
Circus aeruginosus by Jos Zwarts
Temperament
solitary and territorial
Flight Pattern
buoyant low quartering with slow, flexible wingbeats; soaring glider in thermals
Social Behavior
Typically nests singly in extensive reedbeds, building platform nests over water or on dense marsh vegetation. Pairs are monogamous in most cases, and males may perform aerial food passes during courtship. Nesting territories are defended vigorously, especially by the female near the nest.
Migratory Pattern
Partial migrant
Song Description
Generally quiet away from the nest, giving thin, mewing whistles and chirps. Near breeding sites it produces sharper scolding calls and excited chatter during displays and food passes.
