This is Birdnode, the dawn chorus.

Just before sunrise, birds begin to sing.

One by one, then altogether, their voices join to greet the new day.

But which bird sings first?

The timing of when a bird joins the chorus seems to depend on how well it can see and

low light.

Research shows that birds with bigger eyes and larger pupils that let in more light start

to sing before other birds.

A more dense environment like the tropical forests of Ecuador, the first singers are those

birds perched highest in the tree canopy because the light hits that part of the forest first.

As it spreads into the lower levels of the forest, the birds there join the chorus too.

But still, within each level, birds with larger eyes sing first.

That might be because they're the first birds to be able to see predators, so they feel

confident enough to give away their location with song.

Whatever the reason, dawn is when many birds put on their best show, singing faster, louder,

and more frequently than they do at other times of the day.

Take a moment tomorrow morning to step outside and listen.

It's an experience not to be missed.

For birdnought, I'm Michael Stein.