This thesis consists of three chapters describing my investigation of the relationship between American kestrel ecology (i.e., movements and stress response) and plasma corticosterone levels. My initial study at Boise State University focused on the hormonal correlates of avian post-fledging dispersal and how environmental conditions might affect these relationships. I was interested in how a bird may use its own physical condition to assess and respond to variation in environmental conditions. For example, could an external factor, such as food availability, affect an internal timing mechanism involving hormonal fluctuations, and could that, in turn, affect the timing of kestrel dispersal?