Flavescent Warbler

The flavescent warbler is about 14.5 cm (5.7 in) long and weighs 9 to 16 g (0.32 to 0.56 oz). The sexes have the same plumage. Adults of the nominate subspecies have an olive-green crown, a yellow supercilium that becomes olive-yellow past the eye, a dusky stripe through the eye, a yellow crescent under the eye, and yellow 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-pink legs and feet. Subspecies M. f. pallidirostris has a dusky bill and a light olive tinge on the sides and flanks.

The flavescent warbler has a disjunct distribution. Subspecies M. f. pallidirostris is the more northerly of the two. It is found in three populations, in the upper Cauca River valley in central Colombia, from northeastern Colombia intermittently on both slopes of the Venezuelan Andes and the Venezuelan Coastal Range to eastern Miranda state, and in southern Guyana. The nominate subspecies is found from eastern Bolivia east across Brazil south of a line roughly from Rondônia to Ceará. Its range continues south through central Paraguay slightly into northern Argentina's Formosa Province and in Brazil to a line roughly from central Mato Grosso do Sul not quite to the Atlantic in São Paulo state and then north to the coast in central Bahia. The flavescent warbler inhabits dry deciduous and semi-deciduous forest, gallery forest, and shrubby clearings and edges. In elevation it ranges between 200 and 1,000 m (700 and 3,300 ft) in Colombia and between 250 and 1,200 m (800 and 3,900 ft) in Venezuela; in Brazil it ranges from sea level to 1,000 m (3,300 ft).

The flavescent warbler feeds on insects and other arthropods. It forages on the ground or not far above it in vegetation. It hops along the ground and finds prey by turning over leaves with its bill. It forages singly and in pairs and does not join mixed-species feeding flocks.