Birds migrate great distances each year and the primary cue for migration are changes in day length. These changes in day length in turn trigger changes in the birds. Behavior and body cha?

Birds migrate long distances primarily in response to changes in day length, which serve as a key environmental cue. As days grow longer in spring, hormonal changes initiate behaviors such as increased feeding and preparation for the journey. Additionally, physiological adaptations occur, including changes in fat storage and muscle development, enabling birds to endure the demands of migration. This remarkable synchronization with seasonal changes ensures their survival and successful reproduction.