Categories of Western Marsh Harrier
There are a number of relatives included in Circus. aeruginosus, which was then known as "Marsh Harrier". The related taxa are now generally considered to be separate species: the eastern marsh harrier (Circus. spilonotus) and the possibly distinct Papuan harrier (Circus spilothorax) of eastern Asia and the Wallacea, the swamp harrier (Circus. approximans) of Australasia and the Madagascar marsh harrier (Circus maillardi) of the western Indian Ocean islands.
Divisions of Western Marsh Harrier
Western Marsh Harrier is often divided into two subspecies, the widely migratory C. A. aeruginosus which is found across most of its range, and C. A. harterti which is resident all-year in north-west Africa.
Structure of Western Marsh Harrier
Western Marsh Harrier is 43 to 54 cm in length, has a wingspan of 115 to 130 cm and a weight of 400 to 650 g in males and 500 to 800 g (18 to 28 oz) in females. It is a large, bulky harrier with fairly broad wings, and has a strong and peculiar sexual dichromatism. The male's plumage is mostly a cryptic reddish-brown with lighter yellowish streaks, which are particularly prominent on the breast. The head and shoulders are mostly pale greyish-yellow. The rectrices and the secondary and tertiary remiges are pure grey, the latter contrasting with the brown forewing and the black primary remiges at the wingtips. The upper side and underside of the wing look similar, though the brown is lighter on the under wing. Whether from the side or below, flying males appear characteristically three-coloured brown, grey or black. The legs, feet, irides and the cere of the black bill are yellow.
Colours of Western Marsh Harrier
The female Western Marsh Harrier is almost entirely chocolate-brown. The top of the head of Western marsh harrier, the throat and the shoulders have of a conspicuously lighter yellowish colour; this can be clearly delimited and very contrasting, or be more washed-out, resembling the male's head colours. But the eye area of the female is always darker, making the light eye stand out, while the male's head is altogether not very contrastingly coloured and the female lacks the grey wing-patch and tail. The juvenile Western Marsh Harriers are similar to females, but usually have less yellow, particularly on the shoulders.
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