Exploring differences in neophobia and anti-predator behaviour between urban and rural mountain chickadees

Urbanization is changing natural landscapes worldwide, pushing species to quickly acclimate or adapt if they are to survive in urban environments. Mountain chickadees (Poecile gambeli) readily nest in both urban and rural environments without suffering apparent reproductive costs. However, whether urban-nesting chickadees are successful in these environments due to differences in behaviour between urban and rural birds remains untested. We examined the behavioural responses of urban and rural nesting mountain chickadee females when presented with a novel object (red plastic cup) or simulated predator (imitation squirrel model) at the nest. Behavioural responses depended on both the type of model and the habitat. As expected, mountain chickadees responded more strongly to squirrel models than novel objects; however, the magnitude of the difference in response depended on habitat. Urban birds seemingly ignored the novel object, spending little time investigating, and re-entering the nest box quickly. In contrast, rural birds spent more time reacting to the novel object and alarm calling within 5 m of the nest. When presented with a predator model, the urban birds reacted relatively more strongly (compared to the novel stimulus) than rural birds, spending more time within 5 m of the nest and alarm calling. These results suggest that either mountain chickadees in urban environments quickly acclimatize to the presence of novel objects or, potentially, that less neophobic birds disproportionately settle in urban environments or experience positive selection in urban areas. Either way, reduced neophobia may aid in mountain chickadees’ ability to readily and successfully nest in such habitats.