The Lesser Hornero is the smallest member of the genus Furnarius, and is mostly restricted to early successional habitats found on ephemeral sandbar islands along the Amazon River and its larger tributaries. Although it is found from eastern Brazil west along the Amazon into eastern Peru, and up the Napo River into eastern Ecuador, it is highly restricted to riverine habitats. It overlaps with both Pale-legged Hornero (Furnarius leucopus) and Bay Hornero (Furnarius torridus), both of which also favor riverine habitats, but Lesser is considerably smaller and paler than the other species, and more restricted to vegetation that has recently sprung up on sandbars (e.g. Tessaria sp.). In fact it is not known from away from young river-islands. Behavior is much like other species of Furnarius. It is found singly or in pairs, and is often seen walking on the ground, or on exposed logs at the edge of denser vegetation. Its song is a loud raucous descending cackle, similar, but higher pitched than other horneros.