Ornamental Plumage Coloration Interacts with Habitat Urbanization to Predict Problem-Solving in the House Finch Haemorhous mexicanus

Urbanization presents wildlife with many novel environmental challenges and opportunities, including navigating new physical structures and exploiting unique food bases. Thus, animal species that persist or thrive in urban environments may have superior cognitive abilities that allow them to navigate and solve anthropogenic problems. Prior studies have shown neural and behavioral differences between animals inhabiting urban and rural environments, but few have tested cognition-related behavioral responses of animals in an urban context. We administered a novel foraging challenge to caged male House Finches Haemorhous mexicanus - a successful urban and native desert species in the southwestern United States - captured from two urban and two rural locations to examine population differences in problem solving. This task involved opening a tin lid that was slid over the bird's normal small food dish and left only slightly ajar (with no food visible). Male House Finches display exaggerated, sexually selected plumage color that is dependent on diet, so we also tested the hypothesis that more colorful males can better solve foraging problems. We found no differences in problem solving success between urban and rural birds. However, among rural birds, we found that redder males were more likely to solve the foraging task than less-red males. Also, birds that lost more mass during the study were more likely to solve the task, but this was only true among less colorful birds. Our results are consistent with the hypothesis that plumage redness reveals foraging skill in House Finches found in their native environment.