Although Plain-breasted Piculet has a restricted distribution, this species is fairly common within its range. They are primarily found along large rivers in the Amazon basin of north central Peru, and the range extends east along the Amazon River to southern Colombia and extreme western Brazil. Their preferred habitat is young Cecropia forests on river islands, but they also occur in second-growth forest away from rivers. Although generally encountered as singles or pairs foraging in the canopy, these piculets occasionally forage lower down. They frequently join small mixed foraging flocks. Both sexes are very plain overall, lacking any strong barring or spotting on the body. Note especially the entirely black cap in the females, and the lack of black and white nape spotting in the males. The song of Plain-breasted Piculet is a high, thin, descending trill, similar to the song of many other species of piculets.