In this activity, students examine the nature of the interaction between army ants and ant-following birds. Ant-following birds benefit from the relationship by staying just ahead of the ants and capturing prey animals that are disturbed by the ants. While early studies suggested that the birds' foraging might in turn benefit the ants, it is possible that the birds remove prey that the ants would capture. Using figures from a research paper, students determine whether the species interaction is mutualism, commensalism, or parasitism. Students design a hypothetical experiment to measure the effect of birds on army ant foraging success, interpret figures from a real experiment, and consider the consequences of the interaction on the ant colony and the forest community.