Black-faced Antthrush is a medium sized, terrestrial antbird of lowland evergreen forest of tropical Middle America and South America. The species occupies primary forest and mature secondary forest, but tends to avoid scrub and small forest patches. It prefers dense cover, especially during midday, where it forages by walking with a slow, rail-like gait as it picks through leaf litter for arthropods. The gait and posture of this species are typical of those of antthrushes in the genus Formicarius: the tail is cocked almost vertically, and the bird walks with a jerky and wary stride. Generally Black-faced Antthrush is solitary, but it occasionally forages in pairs or joins mixed-species aggregations at army ant swarms. The reclusive habits of this antthrush make it a challenge to see, even in areas where it is common. Although seldom seen, its loud song is one of the most easily recognized crepuscular sounds in Neotropical forests, and although primary song varies markedly across the species’ geographic range, it is distinctive wherever the species occurs. Black-faced Antthrush sings sporadically throughout the day, but it is often one of the first diurnal birds to sing in the morning—it begins at the first hint of civil twilight—and is among the last heard in the evening. Geographic variation in song, in the form of three (and perhaps four) readily distinguishable song types in parapatric portions of the species’ range (see Vocalizations), has led some authorities to split it into multiple species, but detailed research on species limits has not been conducted in contact zones of the song types in southern Honduras and the Colombian Andes.