Narrow-billed antwren

The narrow-billed antwren (Formicivora iheringi) is a species of bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds". It is endemic to eastern Brazil.

The narrow-billed antwren is 11 to 12 cm (4.3 to 4.7 in) long; one male weighed 8.2 g (0.29 oz). The species is sexually dimorphic and has a longish bill and tail. Adult males are mostly dark gray. Their wings and tail are a darker blackish gray, with white tips on the wing coverts and the outer tail feathers. The center of their throat and breast are black, their flanks white, and their undertail coverts have white bars. Adult females have a pale supercilium and a whitish eye ring. They have olive-brown upperparts with a grayer crown; the olive-brown becomes reddish yellow-brown on the uppertail coverts. Their wings are brown with pale cinnamon edges on the coverts and reddish edges on the flight feathers. Their tail is reddish brown. Their underparts are mostly yellow-ochre that is nearly whitish in the center of the belly; their flanks have some white.