Meeting Abstract
Differential migration is where individuals of a given species move to different latitudes depending on their specific age and sex classes. Compared to seasonal migration, where individuals of a species move similar distances with little or no distinct latitudinal variation, differential migration and its underlying mechanisms are less well understood. In migrants, hormones indicating high-energy costs or activity might help determine migratory status. The glucocorticoid corticosterone (CORT) has been documented in several seasonal migrants to increase during migratory avian behavior and is predicted to support the associated physiological and behavioral changes. We explored basal and stress-induced CORT in American goldfinches Spinus tristis; a known partial migratory species where the population consists of individuals that show both migratory and sedentary tendencies. In this species, females and adult males are known to migrate further south than do juvenile males. We therefore investigate a potential mechanistic role of CORT and determine if there are significant differences among age and sex classes. We predict that female and adult male goldfinches have higher CORT levels in comparison to juvenile males during the migratory period. This study contributes to a broader investigation of how glucocorticoids support seasonal life history stages of migratory avian species by comparing the different CORT levels across goldfinch age and sex classes. Understanding the behavioral ecology and physiological mechanisms of migration is important as human disturbance, climate change and other factors influence migratory activity – with implications for overall ecosystem management.
