Cinereous harrier
The cinereous harrier (Circus cinereus) is a South American bird of prey of the harrier family. Its breeding range extends from the Tierra del Fuego through Argentina and Chile to Bolivia, Paraguay, Peru and southern Brasil; and across the Andes north to Colombia. The bird's population is declining but due to its large range is not considered vulnerable. The term cinereous, deriving from the Latin word for ashy, describes its colouration.
Description
The male's plumage is dark grey above with black wingtips and a white rump. The underparts are pale grey, with a rufous streaked belly. The female's plumage is brown above, with a white rump, and cream coloured underneath, with a streaked belly similar to the males. The female is larger than the male with an average size of 46 cm (18 in) compared to the male's 40 cm (16 in). The wingspan is 90–115 cm (35–45 in). Since the 44.5 cm (17.5 in) tail comprises about 56% of this raptor's total length, this species ties with the long-tailed hawk as the raptor with the longest tail relative to its body size.