Gray-and-gold Warbler

The grey-and-gold warbler is about 14 cm (5.5 in) long. Males weigh an average of 12 g (0.42 oz) and females average 12 g (0.42 oz). The sexes have the same plumage. Adults of the nominate subspecies have a lemon-yellow crown stripe with black borders, black lores, and a white streak above the lores on an otherwise blue-gray face. The center of their back is dull olive and the rest of their upperparts are blue-gray. Their wings and tail are blackish gray with blue-gray feather edges. Their chin is white and the rest of their underparts are yellow that is lightest on the undertail coverts. Subspecies M. f. ochraceicrista has an ochraceous-orange crown stripe and is otherwise like the nominate. Both subspecies have a brown iris, a black bill, and yellow-brown legs and feet.

Subspecies M. f. ochraceicrista of the grey-and-gold warbler is the more northerly of the two. It is found in western Ecuador from southern Esmeraldas Province south at least to southern Guayas Province and on Puna Island in the Gulf of Guayaquil. The nominate is found west of the Andes from Chimborazo Province in central Ecuador south into far northwestern Peru's Lambayeque Department. The species inhabits the understory of a variety of landscapes including drier to humid deciduous forest and scrublands. The two subspecies possibly overlap or meet in El Oro Province. In elevation in Ecuador it is mostly found below 400 m (1,300 ft) but reaches 1,700 m (5,600 ft) in the southwest. In Peru it ranges between 400 and 1,800 m (1,300 and 5,900 ft).

The grey-and-gold warbler's diet has not been studied though it is known to feed primarily on invertebrates. It forages mostly in the forest's understory and only occasionally joins mixed-species feeding flocks.