Birds
Antbird
Thamnophilidae · also called antbirds
An antbird has no interest in eating the ants it follows so closely through the rainforest understorey. It is after everything else, the insects, spiders, and small lizards that panic and flee from cover as a marching army ant swarm sweeps the leaf litter below, and at a good swarm several species can gather, jostling for the best position near the front.
Overview
Antbirds, family Thamnophilidae, are a large, diverse family of insectivores found in the rainforest understorey across Central and South America. Many species practise ant-following, tracking army ant swarms to catch prey flushed out by the ants’ advance rather than eating the ants themselves.
A crowded swarm, a strict pecking order
Multiple antbird species, along with other unrelated ant-following birds, can gather at a single productive swarm, often settling into a fairly consistent dominance hierarchy over the best foraging positions. Most species stay tightly bound to intact forest understorey and rarely venture elsewhere.
Status
Least Concern collectively but decreasing for many species, since deforestation and fragmentation threaten both the understorey habitat and, for ant-followers, the large forest areas needed to sustain army ant activity.
Antbird: common questions
Do antbirds actually eat the ants they follow?
Generally no, most ant-following antbird species avoid eating the army ants themselves, which can bite or sting and are not considered a particularly desirable food source, and instead focus on catching the much wider range of insects, spiders, and small animals that flee from cover in a panic as the advancing ant swarm disturbs the leaf litter and low vegetation ahead of it.
Do other bird species besides antbirds also follow army ant swarms?
Yes, ant-following is a foraging strategy practised by a number of unrelated tropical bird species beyond the antbird family itself, and at a particularly large, active swarm, several different ant-following species can gather together, sometimes establishing a fairly consistent dominance hierarchy that determines which individuals or species get preferential access to the most productive positions near the swarm's leading edge.
Are all antbird species ant-followers?
No, the antbird family is large and diverse, containing several hundred species with a range of different foraging strategies, and while ant-following is a well-known and often-studied behaviour associated with the family, only a portion of antbird species are actually dedicated, specialised ant-followers, with many others foraging in different ways entirely unrelated to army ant activity.
Why are antbirds considered especially vulnerable to deforestation?
Most antbird species are closely tied to the shaded, humid understorey layer of intact tropical rainforest and rarely use more open or disturbed habitat, and ant-following species specifically also depend on a large enough area of forest to support the ongoing presence and swarming activity of army ant colonies, meaning forest fragmentation can disrupt both the physical habitat and the specific ecological relationship these birds depend on for foraging success.