Meeting Abstract
Urban adapters are animals that are able to live in human-impacted areas, such as suburbs and cities. It has been hypothesized that urban adapters have behavioral phenotypes that permit them to persist in these human-impacted environments. Indeed, song sparrows (Melospiza melodia) live and breed in both urban and rural habitats and previous research has shown that urban males of this species show greater territorial aggression. However, little attention has been given to female behavior across urban and rural habitats. To determine if living in human-impacted habitats is associated with elevated aggression in female song sparrows, we simulated the intrusion of a conspecific female onto the social territory of focal females at two rural and two urban study sites in Blacksburg, VA. Specifically, we placed a model bird within 5 to 10 m of the focal bird’s nest and played one of 6 exemplars of previously recorded female vocalizations. For 3 minutes without the model and 6 minutes after the model was exposed, we measured the focal female’s distance from the speaker and the number of chitters, chets, growls, and buzzes produced by the female as a measure of aggression. We found that female song sparrows nesting in urban habitats were more likely to respond to a simulated female intruder and showed a greater behavioral response to conspecific intrusions than did females in rural habitats. This pattern of greater female aggression in urban habitats parallels previous reports of greater territorial aggression in males and raises the hypothesis that resource competition may be higher in urban environments, driving increased territorial aggression in both sexes of song sparrows.
