Meeting Abstract
Urbanization represents a dramatic and relatively rapid change in environment, which animals may cope with through phenotypic plasticity. In previous studies, it has been shown that male song sparrows (Melospiza melodia) in urban habitats show higher levels of territorial aggression than their rural counterparts. Such differences in male behavior could have consequences for offspring, as territorial aggression can be traded off against paternal care. Therefore, we compared nestling growth, corticosterone (CORT) levels, and survival among three rural populations (N = 15 nests/30 nestlings) and two urban populations (N=19 nests/45 nestlings) of song sparrows near Blacksburg, VA. We found that nest predation was higher in rural habitats, based on evidence of disturbance at the nest site. Additionally, we found that nestling baseline CORT levels were significantly higher in rural habitats, though there were no differences in overall nestling growth rates. Finally, there was a non-significant trend towards increased nest parasitism by brown-headed cowbirds in urban habitats. These findings suggest that male territorial aggression does have consequences for offspring CORT levels. Additionally, these findings suggest that there are differences in relative risks of predation and nest parasitism across rural and urban habitats, which could potentially drive variation in male territorial aggression.
