The plushcap is one of the most distinctive of all Neotropical passerines in terms of both its appearance and behavior. The plushcap (Catamblyrhynchus diadema) was in its own family until recently when it was grouped with the tanagers. It is very distinct both physically and in terms of behavior. The bill is broad and black. The body is a chestnut color with a bright golden-yellow forecrown. The forecrown is made up of stiff feathers. It has been speculated that these short, dense feathers are less susceptible to feather wear and more resistant to moisture than typical feathers. This may be an adaptation for its specialized feeding mode, in which it probes into dense whorls of bamboo for its prey items (Hilty et al. 1979). Juveniles are just duller versions of their parents. They are found at high elevations from northern Venezuela south to Argentina, including the coastal mountains of Venezuela and the Andes of Colombia, Ecuador, Peru, Bolivia, and extreme northwestern Argentina. They live in montane forests and secondary forests near bamboo. They forage for insects inside the bamboo. They will eat small insects, berries, and small plant matter. The overall length averages 14 cm (5.5 in) and weigh averages 14.1 grams (0.5 oz).
The bird is very distinct and is not confused with many other birds. It stands out from the other tanagers, only possibly being confused with the golden-crowned tanager despite the golden-crowned tanager being blue. The species is found in Argentina, Bolivia, Colombia, Ecuador, Peru, and Venezuela. Its natural habitat is humid montane forests and it is always found in close association with Chusquea bamboo. It is typically found at an elevation 1,800 to 3,500 m.