The relationship between antbirds and army ants is an example of commensalism.
In this relationship, the antbirds benefit by following the army ants as they march through the forest. The ants disturb insects and other small creatures as they move, which the antbirds then feed on. The army ants, however, are neither helped nor harmed by the presence of the antbirds. This one-sided benefit is the hallmark of a commensal relationship.
Commensalism is a type of symbiotic relationship where one organism benefits while the other is neither significantly helped nor harmed. In the case of antbirds and army ants, the antbirds gain a reliable food source, while the army ants are unaffected by the birds’ presence.