Sulphur-bellied Tyrant-Manakin

The sulphur-bellied tyrant-manakin is 13 to 13.5 cm (5.1 to 5.3 in) long and weighs 14 to 19.4 g (0.49 to 0.68 oz). The sexes have the same plumage. Adults have a partially hidden, pale sulphur-yellow stripe on the crown. The rest of their face and their upperparts are dull olive-green. Their wings and tail are a slightly browner olive-green. Their throat is dull grayish white, their upper breast grayish olive, and their lower breast and belly pale sulphur-yellow. They have a pale grayish to creamy or orange-brown iris, a brownish and longish bill, and grayish legs and feet.

The sulphur-bellied tyrant-manakin is a bird of the far western Amazon Basin. One population separate from its main range is found in Peru's Loreto and San Martín departments. Its contiguous range begins in Peru's extreme eastern Cuzco Department and continues east through Ucayali and Madre de Dios departments. From there it continues east into western Brazil's Acre, Amazonas, and Rondônia states. Its range also continues southeast through the northern half of Bolivia. There are also a few widely scattered records in other Brazilian states. The sulphur-bellied tyrant-manakin inhabits humid evergreen forest, especially along rivers with large thickets of bamboo. The separate population in Peru also inhabits semi-deciduous scrublands. In elevation in Peru it mostly occurs below 700 m (2,300 ft) but locally reaches 1,000 m (3,300 ft). In Brazil it occurs below 450 m (1,500 ft).

The sulphur-bellied tyrant-manakin's diet and foraging behavior have not been studied but it is believed to feed mostly on insects and some fruit as well.