Multioscillatory

Although the molecular mechanisms responsible for avian circadian rhythmicity and seasonal migration are still largely unknown [4 ,36 ], evidence strongly suggests locomotor activity and song/call are controlled by a multioscillatory, central clock system coordinating the interplay between major photoreceptor tissues (retina and pineal), encephalic photoreceptors, and pacemakers (retina, pineal, and suprachiasmatic nuclei) [25 ,34 ,37 ].