Plain-breasted piculet endemic to South America on the eastern side of the Andes where it lives in the western part of the Amazon basin. The species is present in southern Colombia, eastern Ecuador, Peru and western Brazil at altitudes of up to . It is found in open parts of humid lowland forests, flooded forests, riverside corridors, swamps, thickets and groves, and logged areas with secondary growth and wooded pastures. It often occurs in areas of young "Cecropia" and "Mimosa" trees. The plain-breasted piculet is usually seen by itself or in pairs, but it will occasionally joins small flocks of birds of
Black-dotted piculet Sucre, a few have finely barred chests. Rare individuals with scaly throats and pale buffy (rather than yellow) underparts resemble the scaled piculet, which can be distinguished by its scaly lower underparts. The crown is black with narrow scarlet streaks on the forepart and conspicuous white dots on the rear part, or throughout in some females. The upperparts are light olive-brown, slightly yellowish, with dusky spots on the shoulders and back. The song is "2 to several extremely high, thin notes, each slightly lower than the preceding, "tseeet, tseeet, tsee," etc." Possibly it is also used as a contact call.