Black-headed Brushfinch

The black-headed brushfinch is about 19 cm (7.5 in) long and weighs about 49.5 g (1.7 oz). The sexes have the same plumage. Adults have an almost entirely black head with a white throat. Their upperparts, wings, and tail are olive-green. The white of the throat continues through the breast and belly. The sides of their breast are gray and their flanks and vent are grayish olive. They have a dark chestnut-brown iris, a black bill, and blackish legs and feet. Juveniles have a greenish olive head and upperparts, dull brown wings and tail, and tawny underparts. Subspecies A. a. tacarcunae is very similar to the nominate but with a faint gray stripe in the middle of the crown and a faint gray supercilium.

The black-headed brushfinch has a highly disjunct distribution. Subspecies A. a. tacarcunae is the more northerly of the two. It is found in Panama in eastern Panamá, eastern Guna Yala (San Blas) , and eastern Darién provinces. The nominate is found discontinuously in the Western, Central, and Eastern ranges of the Colombian Andes. The species inhabits lowland and montane evergreen forest, secondary forest, and elfin forest, where it favors dense undergrowth in the interior and edges. Sources differ on its elevation range. One states it is 700 to 1,000 m (2,300 to 3,300 ft); a more recent one states it is 500 to 1,500 m (1,600 to 4,900 ft). A third places its upper limit at 3,300 m (10,800 ft).

The black-headed brushfinch's diet has not been studied but is known to include insects and seeds. It typically forages singly or in pairs. It forages on the ground, usually under vegetative cover, scratching in leaf litter with its bill.