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Cinereous Harrier
Circus cinereus

DESCRIPTION:
Cinereous Harrier
Gavilán Ceniciento
Circus cinereus
Length: 420mm (male), 500mm (female). Sexes unlike. Male: bill slate grey with black tip; cere yellow; iris likewise; head and neck ash grey; nape feathers are white with a brownish tip and auriculars show a ruff of feathers or facial disc similar to the owls’ (Strigiformes), albeit slightly less conspicuous. Back and scapulars ash grey with brownish spots; uppertail coverts white with fine transversal ash grey bars; rectrices ash grey with very narrow white terminal band and a broader blackish brown subterminal band followed by even narrower blackish brown and reddish cinnamon bands; upper breast ash grey, rest of breast ash grey with alternate white and reddish cinnamon barring; flanks, abdomen, thighs and undertail coverts white profusely barred with undulate reddish cinnamon bands; tail ventrally whitish with blackish brown bands. Wing coverts ash grey spotted with dark brown; secondaries and primaries ash grey, black tipped; ventrally wings show white underwing coverts with grey speckles; axillaries are white narrowly barred reddish cinnamon; primaries and secondaries white with blackish apex. Legs yellow. Female: bill and iris as in male; head and neck greyish brown with whitish facial disc and nape feathers white with dark brown to tip; back and scapulars greyish brown with dark brown spots; uppertail coverts white; rectrices brownish grey with blackish and red cinnamon barring. Breast greyish brown; its lower part spotted buffy white and reddish chestnut; flanks, abdomen, thighs and undertail coverts with wavy buffy white and reddish chestnut barring. Lesser and median wing coverts dark greyish brown with grey and white spots in median coverts; greater coverts grey with blackish spots; primaries and secondaries grey with blackish tips and bands; ventrally primaries are whitish grey with blackish bands and black terminal band; underwing coverts and axillaries buffy white and barred red chestnut. Legs as in male.
Juvenile: head, neck, breast, flanks and abdomen ochraceous buff spotted with dark brown; thighs and undertail coverts buffy ochraceous; back and scapulars dark brown; uppertail coverts buffy white; central rectrices brownish grey; remainder of rectrices ochraceous buff, all with narrow buffy terminal band, dark brown wide subterminal band and other four more narrower bands; ventrally rectrices are whitish grey with a buffy tint and broad dark greyish brown bands. Lesser wing coverts ochraceous buff with dark brown spots; median, greater coverts and secondaries dark brown; primaries brownish grey with blackish banding. Underside of wings show coverts and axillaries buffy ochraceous, with dark brown spots; primaries and secondaries whitish buff, blackish to tip and blackish bands. Cere and legs greenish.
Distinct from other raptor species by its small head and body, the facial disc, long wings, tail and legs. Habitat and behaviour: it glides almost without exception at low altitudes, hesitant flight with wings held in a shallow V; it usually lands directly on ground or perches on low posts, occasionally on branches. It is frequently seen flying; usually solitary, it forages endlessly over stubble fields, grasslands, steppes, plains, marshes and open fields, only alighting to capture prey.
The Cinereous Harrier feeds chiefly on rodents and birds, mainly chicks and also reptiles; to capture them it suddenly interrupts its silent and gliding flight to plunge onto the grass, eating the prey where it has been caught.
Nests are built in the wetlands amidst vegetation, namely reeds and rushes. The nest is made with nearby water plants; clutch size: up to four white eggs. In nesting sites many couples can be found one close to the other.
Range: distributed throughout Patagonia, it occurs also in the centre and northwest of Argentina although it is less common in the latter. In all these regions as well as in Chile, Bolivia, south of Brazil and Uruguay the race found is Circus cinereus cinereus; on Islas Malvinas, the race Circus cinereus histrionicus is endemic.
Illustrated Handbook of the Birds of Patagonia
Kindless: Kovacs Family
 
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Photographs: Mariano Diez Peña


Birding Patagonia • Birdwatcing in Bariloche, Patagonia, Argentina and Chile.
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Photographs on the website: Mariano Diez Peña