Adult Hen Harriers Circus cyaneus show marked sexual dimorphism, but juveniles of both sexes of the European and Asiatic subspecies C. c. cyaneus are generally considered to be very similar to, or practically indistinguishable from, the adult female (Witherby et al. 1943; Peterson et al. 1983; Cramp & Simmons 1980). In North America, the Hen Harrier is considered to belong to a different subsp

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