Exploration Behavior Is Consistent and Associated With Foraging Behavior in Island Songbirds

Abstract

According to the neophobia threshold hypothesis, species with greater dietary specialization should be less exploratory. Few studies have measured the repeatability of exploration behavior of individually marked animals in the wild, so we lack a robust test of the neophobia threshold hypothesis. We tested this hypothesis across six landbird species, including four Darwin's finches, in a species assemblage renowned for its foraging diversity. First, we tested whether color-banded individuals showed consistent exploration behavior across two different contexts: (1) in response to a novel environment, during short-term captivity, and (2) in response to a novel object in the field. Second, to test the predictions of the neophobia threshold hypothesis, we correlated foraging diversity for each species (diversity of foraging substrates and techniques, calculated using the Shannon diversity index) against its mean exploration score. We found that individual differences in exploration behavior in the novel environment were significantly repeatable across a 2-year period (consistent over time) and also correlated with individual differences in exploration towards the novel object (consistent across contexts). Specifically, individuals that visited many sectors in the novel environment also approached the novel object in the field more quickly. At the species level, foraging substrate diversity was positively associated with the proportion of birds to approach the novel object, and species with higher foraging technique diversity were quicker to approach the novel object. These findings are consistent with the neophobia threshold hypothesis. Furthermore, our results suggest that consistent differences in exploration behavior can shape population-level patterns of foraging diversity.