Ecophysiological and behavioral adaptations of birds to rapid urbanization of a desert environment in central Arizona-Phoenix, from 2006 to 2008.

We used Sonoran desert species that have adapted to urbanization to various
degrees to investigate relations between endocrine parameters, in particular plasma
corticosterone in response to acute stress, and aspects of the immune system,
parasite infections, and body condition. Desert residents generally suppressed their
endocrine response to acute stress during the breeding season and underwent marked
seasonal changes in body condition. By contrast, conspecific urban residents tended
to maintain an acute stress response throughout the year and showed subdued seasonal
changes in body condition. We surmise that this difference is related to differences
between desert and urban environments in food resources that birds use to sustain
themselves. The goal of upcoming studies will be to test this hypothesis. In
addition, we are carrying out studies aimed at elucidating the neuroendocrine
mechanisms that mediate differential stress responses seen in birds residing in
rural vs. urban habitats. We are also developing experiments examining relation
between the stress response and the activity of the immune and reproductive system.
The data that we have already collected, and those to be collected in the coming
year, will provide the most extensive set of data to date on effects of urbanization
on wild vertebrates and on the mechanisms that are responsible for these
effects.