Formicariidae is a family of smallish passerine birds of subtropical and tropical Central and South America known as formicariids. They are between 10 and 20 cm (4 and 8 in) in length, and are related to the antbirds, Thamnophilidae, and gnateaters, Conopophagidae. This family contains probably (see below) some 12 species in two fairly small genera. They lay two or three eggs in a nest in a tree, both sexes incubating.