Urban house finches (Haemorhous mexicanus) are less averse to novel noises, but not other novel environmental stimuli, than rural birds

Human-inhabited or-disturbed areas pose many unique challenges for wildlife, including reacting to novel environmental stimuli like car traffic, buildings and anthropogenic noise. Animals inhabiting these environments must adapt to such changes by overcoming such novelty (i.e., neotolerance, neophilia), and either exploiting new resources or avoiding danger. Although many studies have tested animal responses to individual forms of novelty (e.g., human objects, food, urban noise), to our knowledge no study has comprehensively assessed behavioural reactions of urban and rural populations to numerous novel environmental stimuli, including noise. We tested exploratory behaviour of urban, suburban, and rural house finches (Haemorhous mexicanus) in response to four different types of novelty (novel structural environment, novel object, novel noise, and novel food) in separate captive experiments, while also recording each bird for 30 min before exposure to determine baseline activity level. Although we found few population-level differences in behavioural responses to novel objects, environment, and food, we found significant differences in how finches from different sites responded to novel noises. When played a novel sound (whale call or ship horn), urban and suburban house finches approached their food source more quickly and spent more time on it than rural birds, and urban and suburban birds were more active during the ship-noise presentation. These results indicate that, in comparison with other types of novel stimuli, anthropogenic noise may be a key driver of urban adaptation in birds and its influence may vary depending on the type of sound.