Personality predicts collective behavior in greylag geese: Influencers are bold and followers are exploratory

Simple interaction rules describe the coordination of individual behavior into collective behavior. However, we lack long-term tests of individually tagged individuals in the wild to understand fitness payoffs of different social roles during collective movement. Here, we interrogate leader-follower roles in greylag geese (Anser anser) in relation to personality traits (boldness, aggressiveness, and exploration). We calculated an influencer score based on the number of followers for sub-group movement events across four years. Influencer score was weakly but significantly repeatable over time, and all three personality traits were repeatable. Greylag geese with higher influencer scores were bolder, and geese that were first to follow a non-partner influencer goose were more exploratory and more likely to look behind the mirror during a mirror stimulation test. In light of these findings, we discuss potential individual-level benefits of following a bold individual and the presumed group-level benefits of new information spread via followers open to novelty.