Black-crested Warbler

The black-crested warbler is about 13.5 cm (5.3 in) long and weighs about 11 to 20 g (0.39 to 0.71 oz). The sexes have the same plumage. Adults have a narrow black crown stripe, a wide yellow supercilium, a black stripe through the eye, a yellow crescent under the eye, and olive-green cheeks and ear coverts. Their nape, upperparts, wings, and tail are olive-green. Their throat and underparts are yellow. They have a dark iris, a blackish bill, and orange-yellow legs and feet. Juveniles have a dusky olive-gray head and upperparts and pale buffy-olive underparts. Their bill is paler than adults'.

The black-crested warbler has a highly disjunct distribution. It is found in the Venezuelan Coastal Range from Aragua to Miranda, in the Serranía del Perijá on the Venezuela-Colombia border, in the Venezuelan Andes from northern Trujillo and south into the northern part of Colombia's Eastern Andes, and in Colombia's Central and Western Andes south through the Andes of Ecuador into Peru. In Peru it is on the western Andean slope south to southern Cajamarca Department and on both slopes in the Marañón River valley. The black-crested warbler inhabits the edges and clearings of montane forest, cloudforest, and mature secondary forest, all with dense understory, and shuns shuns their interiors. In some areas if favors stands of Chusquea bamboo and areas with bracken (Pteridium). In somewhat more open landscapes it frequents hedgerows. In Venezuela it ranges in elevation between 1,800 and 2,200 m (5,910 and 7,220 ft) in the Coastal Range and between 2,000 and 3,100 m (6,560 and 10,170 ft) in the Andes. It ranges between 2,300 and 3,400 m (7,550 and 11,150 ft) in Colombia, mostly between 2,000 and 3,500 m (6,560 and 11,480 ft) in Ecuador, and between 1,800 and 3,300 m (5,910 and 10,830 ft) in Peru.

The black-crested warbler's diet has not been studied but is assumed to be mostly or entirely invertebrates. It forages mostly in pairs, on the ground or not far above it in vegetation. It takes prey by gleaning from dense low undergrowth but will do so in the higher levels of the understory. In the non-breeding season it sometimes joins mixed-species feeding flocks.