Perching bird Formicarius belonging to the family Formicariidae, order Passeriformes. These birds, which range from 10 cm/4 in to 20 cm/8 in long, are found in Central and South America; they feed largely on ants. Species include Formicarius colma, the colma ant thrush.

In Britain, the genus Chamaeza is also called ant thrush, and comprises four species, including the short-tailed ant thrush C. brevicauda which has a length of 20 cm/8 in.