WHEN DO BIRDS SING?

Around Winter Solstice.

For many animals, the night/day cycle is their calendar. The photoperiod is a key factor in when birds migrate, and when they begin to sing and nest. I am amazed at how quickly the changing photoperiod registers with birds. Within a week or 10 days of the solstice, the faint murmurings of the song sparrow and black-capped chickadee begins. Ducks court with extra vigour. The photoperiod control over bird’s behaviour is honed by natural selection. The duration of light and dark sets off a physiological response that stirs the behaviour of birds.

The seasons of birdsong follow the seasons of the sun. As the sun dips low in the winter sky, the northern woods fall quiet; those few birds who remain call softly as they search for food to survive the short days and long cold nights. As the sun makes its comeback, beginning late December on the winter solstice, so too does song; gonads grow and hormones surge through transforming bodies, the urge to sing now irrepressible as thoughts of these same birds turn to seeking mates for the coming spring.