Yellow-breasted antwren

The yellow-breasted antwren (Herpsilochmus axillaris) is a species of bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds". It is found in Colombia, Ecuador, and Peru.

The yellow-breasted antwren is 11 to 12 cm (4.3 to 4.7 in) long and weighs 10 to 13 g (0.35 to 0.46 oz). Adult males of the nominate subspecies H. a. axillaris have a black crown and nape with white spots on the crown and a broken whitish supercilium on an otherwise mottled blackish and yellow-olive face. Their upperparts are olive-gray. Their wings coverts are black with yellow-tinged white edges and tips; their flight feathers are very dark gray. Their tail is mostly dark gray, with white tips and part of the edges of the inner feathers and mostly white outer feathers. Their throat and underparts are mostly pale yellowish olive with a yellow center to the belly. Adult females have a cinnamon-rufous crown, olive-buff upperparts, and darker olive underparts except for the yellow belly center. Their wings and tail are like the male's.

Males of subspecies H. a. senex are paler than the nominate, with spots only on the center of their crown and a grayish white throat and breast. Males of subspecies H. a. puncticeps have olive-tinged and grayer upperparts than the nominate and less white on their tail feathers. Females have a dark olive-gray crown with a cinnamon-rufous tinge. Males of subspecies H. a. aequatorialis also have olive-tinged and grayer upperparts than the nominate. Their crown spots are only in the center; they have mostly pale yellow underparts with an olive wash on the sides.