Meeting Abstract
Flexible and reversible phenotypes across the annual cycle allow birds to match fluctuating environmental and ecological demands. Varying energetic demands associated with time of year have been demonstrated to drive metabolic and muscle plasticity in birds, and this study examines physiological plasticity in organismal metabolism, muscle structure, and muscle metabolism. Across the Gray Catbird’s annual cycle, cold induced metabolic rate (VO2summits) is highest during migration and lowest during tropical wintering. Heart and flight muscle mass is greatest during migratory periods compared to non-migratory periods. Mitochondrial function of the pectoralis muscle remained constant across the annual cycle as quantified by aerobic regulatory enzyme activities (citrate synthase and cytochrome C oxidase). The Gray Catbird displays phenotypic plasticity at the organismal and tissue levels during migration compared to non-migratory periods.
