Scientific name: Circus cyaneus (Linnaeus, 1766)
Bird group: Birds-of-prey
Field characters. Length 44-52 cm; wingspan 100-120 cm. Differs from Pallid Harrier and Montagu's Harrier in more conspicuous white patch on rump, larger size and broader Northern Goshawk-like wings. Male blue-grey with dark grey trailing edge to wing; lacks wingbars of Montagu's and has darker head and breast than Pallid, with larger black wingtips. Female has dark brown upperparts and buff-brown underparts streaked dark brown. White patch on rump lighter and more extensive than in Pallid and Montagu's (but differences not always diagnostic); wings broader and heavier with five fingers (Pallid and Montagu's have four); facial pattern less pronounced with faint collar and without conspicuous dark ear-covert patch. Juvenile very similar to female and thus differs from young Pallid and Montagu's by streaked underparts. Flies in typical harrier fashion with several wing-beats interspersed with glides on wings held in shallow V.
Voice. Usual call is a rapid chatter "ke ke ke ke...."; also produces a plaintive "piih-e".
Distribution. Rather local and scarce breeding bird; northern and north-eastern populations winter over most of Europe.
Habitat. In breeding season, occurs on heather moorland, grasslands, sand-dunes, open marshes, open taiga. More widespread outside the breeding season, when it prefers heaths, marshes, arable farmland, and marshy areas.
Food. Catches prey by surprise through quartering over ground and seizing prey with sudden pounce. Diet consists mainly of young and adult songbirds, young nidifugous birds and small rodents.
Eggs. Often uniform, rarely with few red-brown blotches. Ground colour bluish white/greenish, gradually becoming whiter. Texture fine granular, chalky, not glossy. Shape subelliptical/short subelliptical. Size 46 x 36 mm (40-52 x 32-40), weight 31 g (calculated weight). Close to eggs of Montagu's Harrier.