The antbirds are a large passerine bird family, Thamnophilidae, found across subtropical and tropical Central and South America, from Mexico to Argentina.

Thamnophilidae was removed from Formicariidae, leaving behind the antthrushes and antpittas, due to recognition of differences in the structure of the breastbone (sternum) and syrinx, and Sibley and Ahlquist's examination of DNA–DNA hybridization.

The Thamnophilidae are now thought to occupy a fairly basal position within the infraorder, i. e. with regard to their relatives the antthrushes and antpittas, tapaculos, gnateaters, and also the ovenbirds.

The names refer to the relative sizes of the birds (increasing in the order given, though with exceptions) rather than any particular resemblance to the true wrens, vireos or shrikes.

[4] The results also confirmed suspicions of previous researchers that some species, most notably in Myrmotherula and Myrmeciza, need to be assigned to other genera.

Still, due to the difficulties of sampling from such a large number of often poorly known species, the assignment of some genera is still awaiting confirmation.

[5] In general terms, "antshrikes" are relatively large-bodied birds, "antvireos" are medium-sized and chunky, while "antwrens" include most smaller species; "antbird" genera can vary greatly in size.

Members of this family have short rounded wings that provide good manoeuvrability when flying in dense undergrowth.

Longer tarsi typically occur in genera such as the Thamnophilus antshrikes that forage by perch-gleaning (sitting and leaning forward to snatch insects from the branch), whereas shorter tarsi typically occur in those that catch prey on the wing, such as the Thamnomanes antshrikes.

Overall the pattern within the family is for the males to have combinations of grey, black or white plumage and the females having buff, rufous and brown colours.

[9] Many species of antbirds have a contrasting 'patch' of white (sometimes other colours) feathers on the back (known as interscapular patches), shoulder or underwing.

Pairs in neighbouring territories judge the proximity of rivals by the degradation of the song caused by interference by the environment.

The Yapacana antbird, for example, is restricted to the stunted woodlands that grow in areas of nutrient-poor white-sand soil (the so-called Amazonian caatinga) in Brazil, Venezuela and Colombia.

[17] Genetic comparison of the whole genomes of higher and lower-humidity antbirds have shown some differences in genes linked to water balance and temperature regulation.

Larger species can kill and consume frogs and lizards as well, but generally these do not form an important part of the diet of this family.

It does not use its feet to scratch the leaf litter, as do some other birds; instead it uses its long bill to turn over leaves rapidly (never picking them up).

Loud and distinctive calls and conspicuous plumage are important attributes of nuclear species as they promote cohesion in the flock.

[10] The benefits of the mixed flock are thought to be related to predation, since many eyes are better for spotting predatory hawks and falcons.

[13] Swarms of army ants are an important resource used by some species of antbird, and the one from which the family's common name is derived.

Obligate ant-followers visit the nesting bivouacs of army ants in the morning to check for raiding activities; other species do not.

[14] Because army ants are unpredictable in their movements, it is impractical for obligate ant-followers to maintain a territory that always contains swarms to feed around.

Ocellated antbirds have an unusual social system where the breeding pair forms the nucleus of a group or clan that includes their male offspring and their mates.

Antbird nests are cups of vegetation such as twigs, dead leaves and plant fibre, and they follow two basic patterns: either suspended or supported.

Antbirds are common components of the avifauna of some parts of the Neotropics and are thought to be important in some ecological processes.

[31] Nests, including incubating adults, chicks and eggs, are vulnerable to predators, particularly snakes but also nocturnal mammals.

[33] This has resulted in a number of behaviours by the ants in order to reduce kleptoparasitism, including hiding of secured prey in the leaf litter and caching of food on trails.

The fragmentation of forests into smaller patches affects species that are averse to crossing gaps as small as roads.

Smaller forest fragments are unable to sustain mixed-species feeding flocks, leading to local extinctions.

Numerous species of antbird formerly resident in the area were extirpated, in no small part due to increased levels of nest predation on the island.

[5] Some are also extremely poorly known; for example the Rio de Janeiro antwren is known only from a single specimen collected in 1982, although there have been unconfirmed reports since 1994 and it is currently listed as critically endangered.