Meeting Abstract

P2.168  Thursday, Jan. 5  Aggression, neophobia and corticosterone in relation to urbanization in song sparrows (Melospiza melodia) FOLTZ, Sarah L.*; DAVIS, Jason E.; GREENE, Virginia W.; LAING, Brenton T.; TALLANT, James A.; MOORE, Ignacio T.; Virginia Tech; Radford University; Virginia Tech; Virginia Tech; Virginia Tech; Virginia Tech

Continued growth of urban and suburban areas permanently changes habitats and disrupts native species. Although some native animals are able to inhabit urbanized areas, previous studies have shown that urban living can be related to changes in stress hormone levels and in behaviors such as conspecific aggression and neophobia (fear of novel objects). Here we compare corticosterone (the major avian stress hormone), conspecific aggression, and neophobia in male song sparrows (Melospiza melodia) across suburban and rural habitats in southwestern Virginia. Behaviors were measured using modified simulated territorial intrusions in which we introduced a novel or control object while playing recorded conspecific male song on the focal bird’s territory. We found a significant positive correlation between urbanization and aggression. In addition, all birds exhibited reduced aggression in the novel test, and the magnitude of this reduction was the same across groups. Thus, while suburban birds responded more aggressively than rural birds to both novel and control tests, we found no difference in neophobia between suburban and rural birds. No relationship was found between corticosterone and either behavior or urbanization. We conclude that either urban living increases conspecific aggression in song sparrows or aggressive individuals are better able to colonize urbanized habitats.