This, the northwestern representative of the ‘professional’ antbird genus Rhegmatorhina occurs in southeast Colombia through adjacent northwest Brazil entirely west of the Rio Negro. The species appears to prefer tropical evergreen forest on nutrient-poor, sandy soils, and it is perhaps entirely confined to such areas. Its range is not easy to penetrate and comparatively few natural history observations had been published for this species until recently. The Chestnut-crested Antbird feeds on arthropods, which are usually flushed by the army ant swarms that the birds follow for the majority of each day. It joins other obligate ant-following birds, including White-chinned Woodcreepers (Dendrocincla merula) at these swarms, the different individuals constantly attempting to displace each other and all the while uttering harsh, churring calls, but this species is apparently always subordinate to Reddish-winged Bare-eyes (Phlegopsis erythroptera) when the latter is present. Nothing is known concerning this antbird’s breeding ecology. Like its congeners, the Chestnut-crested Antbird is a striking-looking bird, the largely rufous and brown plumage made replete by the black face and throat, and bluish-gray periorbital skin.