Season- and context-dependent sex differences in melatonin receptor activity in a forebrain song control nucleus

► There is dramatic regulation of melatonin receptor activity in Area X in starling brain. ► Regulation of melatonin receptor differs depending on the context in which birds are housed. ► The timing of regulation of melatonin receptor activity differs between males and females. ► The magnitude of change in melatonin receptor activity is the same in both sexes.