Buckley's forest falcon (Micrastur buckleyi), also called lesser collared forest-falcon and Traylor's forest-falcon, is a species of bird of prey in subfamily Herpetotherinae of family Falconidae, the falcons and caracaras. It is found in Brazil, Eucador, Peru, and possibly Colombia and Venezuela. Taxonomy and systematics Buckley's forest falcon was previously considered to be a variant of the collared forest falcon (M. semitoquatus). The two of them and the slaty-backed forest falcon (M. mirandollei) are sister species. It is monotypic. Description Buckley's forest falcon is long. Its wingspan is . Adult males have black upperparts with a white collar. Their cheeks, throat, and underparts are white and unmarked. Their tail is black with three narrow white bars on the inner feathers and four on the outer ones. Their iris is dark brown, their cere, lores, and bare skin around the eye are dull greenish, and their legs and feet are yellowish. Adult females are like males with the addition of white spots on their scapulars and secondaries. Juveniles are also black above but have a buffy breast and dark bars on the belly. Distribution and habitat Buckley's forest falcon is known from only a few specimens, photographs, and sightings. Specimens confirm its presence in extreme western Brazil, eastern Ecuador, and eastern Peru. A few sight records in Colombia and Venezuela lead the South American Classification Committee of the American Ornithological Society to classify it as hypothetical in those two countries. Most of the records are from lowland tropical and subtropical forest at elevations between but one specimen was collected at in Ecuador and there is a record at in Peru. Behavior Movement Buckley's forest falcon is assumed to be a year-round resident. Feeding Almost nothing is known about the diet or hunting techniqe of Buckley's forest falcon. One specimen had a small Mesomys arboreal rat in its stomach. The species' small feet suggest that birds are only a minor part of its diet. Breeding Sightings of Buckley's forest falcon fledglings suggest that its breeding season includes April to early August. Nothing else is known about its breeding biology though it is assumed to nest in tree cavities like other Micrastur forest falcons. Vocalization The most common Buckley's forest falcon vocalization is "a far-carrying, nasal "eeok, oow" or "eeok, oow...ow", repeated...for long periods, mainly at dawn." It also occasionally makes "a long rising series of "kaw" notes followed by 2-3 falling "aauw"