White-bellied Pygmy-Tyrant Myiornis albiventris

A tiny puffball of feathers that looks like a bumblebee crossed with a down pillow. Minute size and compact shape prevent confusion with most other species, but also note the faint dusky streaking on whitish underparts, indistinct black crescent behind the eye, and olive-yellow upperparts. Found in both secondary and primary humid woodland, but can be difficult to spot as it moves in the canopy of tall trees. Its song is an easily overlooked, insect-like short, fast trill that accelerates into a buzz.