Large, stout-billed woodcreeper of tall rainforest in southeastern Amazonia. Plumage entirely rufous-brown with no barring or streaking; note thick dusky-reddish bill, plain face, and brownish throat (not contrastingly white). Found in tall rainforest as well as slightly lower-stature forests on sandy soils; generally less common than other large woodcreepers. Climbs along tree trunks and large branches at middle and upper levels, probing bark crevices for insects and small vertebrates; occasionally follows army ant swarms to capture animals fleeing up tree trunks. Heard more often than seen. Song, given mainly at dawn, is a far-carrying, hoarse whistle repeated 3–4 times, very unlike other woodcreepers. Amazonian Barred-Woodcreeper, which also has a reddish bill, may occur with Uniform at ant swarms and be mistaken for it in dim understory light; note Uniform’s stouter bill and plainer plumage.