Meeting Abstract
Urbanization is a critical environmental change that can impact endocrine function, physiology, and behavior of wild birds. Behavioral differences, particularly in territorial aggression, have been previously described in male song sparrows living in urban and rural habitats, with urban males behaving more aggressively to playback. Such behavioral differences must be underpinned by differences in the brain, yet little work has explored how urbanization and neural function may be interrelated. We explored the role of neural activation within a network of brain regions, collectively called the social behavior network, that regulates social behaviors, including territorial aggression. Specifically, we played free-living, territorial male song sparrows conspecific songs for 6-15 minutes, captured them, collected their brains, and measured an immediate early gene (Fos). We also collected a blood sample to measure circulating testosterone. We found that Fos immunoreactivity differed in rural and urban birds across several brain regions, including two regions specifically implicated in male territorial behavior (the lateral septum and bed nucleus of the striaterminalis) with rural males showing higher neural activation than urban males. This difference was not explained by the duration of playback, date or time of testing, or plasma testosterone. Though future work linking territorial behavior with patterns of neural activation in response to song playback is needed, these results implicate the social behavior network in regulating well-established differences in territorial behavior among song sparrows living in rural and urban habitats.
