Meeting Abstract
Natural environments are unpredictable and the survival of organisms depends on their ability to respond to environmental challenges and perturbations. Therefore, energy mobilization in response to challenges could be a good predictor of survival. Acute challenges initiate a suite of physiological responses including activation of the sympathetic nervous system and hypothalamic-pituitary-adrenal axis. Collectively these responses promote energy mobilization and resource allocation to support survival and therefore may influence return rate. We utilized a free-living population of Mountain White-crowned Sparrows to characterize the glucocorticoid and hyperglycemic response to acute challenge. We then modeled predictors of these responses and individual return rates over several years. Potential predictors of glucose and glucocorticoid mobilization were scaled body mass, fat score, hematocrit, sex, date, year, and bleed delay time. Potential predictors of return rate were glucose and glucocorticoid mobilization as well as body condition (fat, mass, and scaled mass) and year. We predict that blood glucose and glucocorticoid levels will respond positively to challenge, as seen in previous studies, and that body condition and fat score will be positive predictors of glucose mobilization. For return rate, we expect a positive relationship with glucose mobilization and body condition. This study is unique in that we investigate the potential link between energy mobilization and year-to-year survival in a free-living migratory species.
