Hen Harrier (Circus cyaneus)

Closely related to C. cinereus, with which it has been considered conspecific. Until recently, considered conspecific with C. hudsonius, which differs in having (first three characters in male) throat and upper breast greyish-white with mid-brown streaking vs pure blue-grey (ns[2]); lower breast to belly white with heavy mid-brown streaking turning to spotting on lower underparts and thighs vs pure white (3); upperside of outer primaries black and shading to grey basally vs all black (2); in female, underparts a shade darker (ns[1]); in juvenile, underparts rich dark rufous with sparse dark streaking vs pale brownish-buff with heavy dark streaking (3). Distinct from C. cinereus on account of (first two characters in male) throat and upper breast greyish-white with mid-brown streaking vs pure blue-grey (ns[2]); lower breast to belly white with heavy mid-brown streaking turning to spotting on lower underparts and thighs vs white with dense rufous barring (3); trailing edge of underwing dark grey vs mid-grey, weaker on primaries (2); in female, underparts heavily streaked, not barred (3). Occasionally hybridizes with C. macrourus#R. Monotypic.