Ant followers are

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s that feed by following swarms of

army ant The name army ant (or legionary ant or ''marabunta'') is applied to over 200 ant species in different lineages. Because of their aggressive predatory foraging groups, known as "raids", a huge number of ants forage simultaneously over a limi ...

s and take prey flushed by those ants. The best-known ant-followers are 18 species of

antbird The antbirds are a large passerine bird family, Thamnophilidae, found across subtropical and tropical Central and South America, from Mexico to Argentina. There are more than 230 species, known variously as antshrikes, antwrens, antvireos, fir ...

in the family Thamnophilidae, but other families of birds may follow ants, including thrushes,

chat Chat or chats may refer to: Communication * Conversation, particularly casual * Online chat, text message communication over the Internet in real-time * Synchronous conferencing, a formal term for online chat * SMS chat, a form of text messagin ...

s, ant-tanagers,

cuckoo Cuckoos are birds in the Cuculidae family, the sole taxon in the order Cuculiformes . The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals and anis. The coucals and anis are sometimes separ ...

s, motmots, and

woodcreeper The woodcreepers (Dendrocolaptinae) comprise a subfamily of suboscine passerine birds endemic to the Neotropics. They have traditionally been considered a distinct family Dendrocolaptidae, but most authorities now place them as a subfamily o ...

s. Ant followers may be obligate, meaning that they derive most of their diet by following ant swarms, or non-obligate, meaning they derive only some of their diet from this behaviour. Some species may feed extensively at ant swarms yet may not be obligate ant followers, being able to and regularly feeding away from the swarms as well. Many species of tropical

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of ...

s form large raiding swarms, but the swarms are often

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

or raid underground. While birds visit these swarms when they occur, the species most commonly attended by birds is the

Neotropical The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...

species ''

Eciton burchellii ''Eciton burchellii'' is a species of New World army ant in the genus '' Eciton''. This species performs expansive, organized swarm raids that give it the informal name, ''Eciton'' army ant. This species displays a high degree of worker polymor ...

'', which is both diurnal and surface-raiding. It was once thought that attending birds were actually eating the ants, but numerous studies in various parts of ''E. burchellii's'' range has shown that the ants act as beaters, flushing insects, other arthropods and small vertebrates into the waiting flocks of "ant followers". Because ''E. burchellii'' is the only regular diurnal army ant specialised and regular ant-followers mostly occur in its

range, but

Afrotropical The Afrotropical realm is one of Earth's eight biogeographic realms. It includes Africa south of the Sahara Desert, the majority of the Arabian Peninsula, the island of Madagascar, southern Iran and extreme southwestern Pakistan, and the island ...

birds do follow driver ants in the genus '' Dorylus''. It was once suggested that the relationship between the obligate and regular ant-followers and the army ants, particularly ''Eciton burchellii'', was mutualistic, with the ants benefiting by having the birds chase prey back down towards them. However experiments where ant followers were excluded have shown that the foraging success of the army ants was 30% lower when the birds were present, suggesting that the birds' relationship was in fact

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

. This has resulted in a number of behaviours by the ants in order to reduce

kleptoparasitism Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when ...

, including hiding of secured prey in the leaf litter and caching of food on trails. It has been suggested that the depressive effect of this parasitism slows the development of ''E. burchellii'' swarms and in turn benefits other ant species which are preyed upon by army ants. Despite the easier availability of prey, ant followers face an element of risk, as these small birds can be killed by four stings from fire ants.Ant Army Invasion! – Wild South America – BBC
YouTube (2009-02-27). Retrieved on 2013-02-23.

References

{{Reflist Bird behavior Biological pest control Ants