Meeting Abstract

P3.10  Thursday, Jan. 6  Subspecies comparisons of the physiological mechanisms regulating the traits of migratory and resident White-crowned Sparrows, Zonotrichia leucophyrs NEMETH, Z*; KRAUSE, J; CAMPION, A; RAMENOFSKY, M; Univ. of California, Davis; Univ. of California, Davis; Univ. of California, Davis; Univ. of California, Davis znemeth@ucdavis.edu

Every spring billions of birds migrate north to breed then return to the south to overwinter, each site offering seasonal resources that increase overall fitness. The energy to fuel migratory flight is stored, used and replenished repeatedly in the form of lipids and protein throughout the migratory periods. The physiological mechanisms associated with energy metabolism during preparation for migration and arrival at the breeding and wintering grounds however, are poorly understood. In order to identify specific traits associated with migration, we compared two subspecies of White-crowned Sparrow: a long distance migrant, Z.l gambelii and a resident, Z.l. nuttalli. For migrants we sampled at both the wintering (Davis, CA) and breeding (Fairbanks, AK) grounds during the periods of (a) preparation for spring migration, (b) arrival at the breeding ground, (c) preparation for fall migration and (d) arrival at the wintering ground and commensurate times for the resident birds (Bodega Bay, CA). Here, we present seasonal profiles for body mass and fat scores, baseline and stress induced levels of plasma corticosterone, corticosterone binding protein (CBG), morphological and histological data of lipid and muscle stores, and plasma metabolites. To date, migrant profiles show seasonal accretion and utilization of mass and protein associated with seasonal migratory departure and arrival; whereas, the residents show little change throughout. This has led to the suggestion that the traits associated with migration have been lost with resident life history.