Interspecific information use by army-ant–following birds

Abstract

ABSTRACT Many animals use cues from other species to gather information about foraging opportunities, but engaging in such behavior requires balancing the potential benefits with the risks of increased competition. Neotropical birds that follow army ants are an appropriate system within which to study such eavesdropping behavior. Mixed-species groups of these understory birds congregate around ant swarms, where they forage on insects flushed by the ants. Obligate ant-followers have specialized behaviors to track ant swarms and may serve as information sources for facultative ant-followers. Owing to strong dominance hierarchies among species, however, the value of the information likely depends on the competitive relationship between the information provider and the eavesdropper. I investigated whether ant-following birds preferentially followed the songs of some antbird species over others, testing the prediction that the vocalizations of small (subordinate) ant-following species would attract more indivi...