Biological clocks help reduce the physiological conflicts in avian migrants

摘要: We present evidence from experiments on overwintering populations of two Palearctic-Indian latitudinal migratory birds, the black-headed bunting (Emberiza melanocephala) and red-headed (E. bruniceps), that bird’s clock in interaction with day length regulates seasonal rhythms migration reproduction such physiological conflict between them is reduced. Initiation termination body mass testicular cycles are separately regulated photoperiodic events. For example, under stimulatory photoperiods response curve does not overlap growth. A response-specific photoperiodism adaptive, since gain mass, critical to spring migration, precedes gonadal recrudescence. Finally, as indicated by night-time restlessness experimental situations (e.g., intense locomotion caged condition-called Zugunruhe) appears be a separate circadian oscillator.