Physiological mechanisms of migratory traits

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This proposal focuses on both spring and fall migrations of White-crowned Sparrows. The primary goal of this research is to determine the physiological mechanisms regulating migratory traits and the environmental signals birds rely upon for preparation and completion of each journey. Although spring and autumn migrations cover the same distance, all other facets of these trips are different and birds have evolved distinct strategies to complete each successfully. The underlying physiological bases have as yet to be rigorously investigated and the investigator posits that understanding these mechanisms is of growing concern as many migrant populations are declining rapidly owing to marked changes in the environment and loss of habitat. The proposed studies take advantage of two sub-species of White-crowned Sparrow, one that migrates long distances and one that no longer migrates and is resident. The investigator proposes to examine 1) the differences in muscle development and fat storage in the two subspecies as one prepares for spring migration and the other does not; 2) the different hormonal mechanisms involved in the spring and fall migrations, and 3) differences in preparation for the fall migration between young and adult birds. Results from this study may offer new insights into the mechanisms regulating migration while directing further investigations to define the cellular bases that influence the potential success or failure of a migratory population. The project would support a postdoctoral researcher, a graduate student and involve several undergraduate assistants. Outreach to the public would occur in California and Alaska through established collaborations between the investigator and the SLEWS (student and landowner education watershed stewardship) program associated with the Audubon Farm and Center for Land-based Learning and the Alaska Bird Observatory, respectively.