Supplementary material from "What makes specialized food-caching mountain chickadees successful city slickers?"

There were no significant differences between urban and forest chickadees in neophobia, food-caching rates, spatial memory acquisition, hippocampus volume or the total number of hippocampal neurons. Our results partially support the idea that some traits associated with behavioural flexibility and innovation are associated with successful establishment in urban environments, but differences in long-term spatial memory retention suggest that even this trait specialized for food-caching may be advantageous.

Our results highlight the importance of environmental context, species biology and temporal aspects of invasion in understanding how urban environments are associated with behavioural and cognitive phenotypes and suggest that there is likely no one suite of traits that makes urban animals successful.