Behavioral flexibility is related to foraging, but not social or habitat use behaviors, in a species that is rapidly expanding its range

The ability of other species to adapt to human modified environments is increasingly crucial because of the rapid expansion of this landscape type. Behavioral flexibility, the ability to change behavior in the face of a changing environment by packaging information and making it available to other cognitive processes, is hypothesized to be a key factor in a species’ ability to successfully adapt to new environments, including human modified environments, and expand its geographic range. However, most tests of this hypothesis confound behavioral flexibility with the specific proxy aspect of foraging, social, or habitat use behavior that was feasible to measure. This severely limits the power of predictions about whether and how a species uses flexibility to adapt behavior to new environments. To begin to resolve this issue, we directly tested flexibility using two measures (reversal learning and puzzlebox solution switching) and investigated its relationship with foraging, social, and habitat use behaviors in a flexible species that is rapidly expanding its geographic range: the great-tailed grackle. We found relationships between flexibility and foraging breadth and foraging techniques, with the less flexible individuals using a higher proportion of human foods and having more human food sources within their home range, suggesting that they specialize on human foods. These relationships were only detectable after a flexibility manipulation where some individuals were trained to be more flexible via serial reversal learning and compared with control individuals who were not, but not when using data from outside of the flexibility manipulation. There were no strong relationships between flexibility and social or habitat use behaviors. Given that this species is rapidly expanding its geographic range and recently shifting more toward urban and arid environments, our findings could suggest that foraging breadth and foraging technique breadth are factors in facilitating such an expansion. Overall, this evidence indicates that cross-species correlations between flexibility and foraging, social, and habitat use behaviors based on proxies have a high degree of uncertainty, resulting in an insufficient ability to draw conclusions.