The Rufous-capped Nunlet is a small, brownish puffbird of Amazonia. It has a particular fondness for patches of bamboo, but can be found in similar habitats such as second growth, dense vines, and Tessaria scrub, often near rivers or wetlands. It has brown upperparts, a chestnut cap, rufescent underparts, and a gray cheek and neck. Pairs move through the understory and middle levels of vegetation, often perching in one place for a time and wagging their tales in an odd, jerking pendulum motion. There is very little information on the feeding or breeding behavior of this species, although it apparently eats insects. It occurs in southern Amazonia from Peru east to central Brazil, where it is the only nunlet with a chestnut crown.