This is Bird Note.

Peer into the world of birds and eyes of many different colors peer back.

There are shades of light and dark, yellows, whites, greens, the red eyes of certain hawks, ducks, loons,

herons, and songbirds. These colors really pop, because birds have no white around the iris like we do.

So the yellow eyes of a great horned owl or a herring gull seem to give the birds a fierce, penetrating glare.

While eye color isn't tied to one group of birds or another,

a pattern common to many birds is a change in eye color as immature birds grow to adulthood.

Bald eagles, ring-billed gulls, ducks such as golden eye and scalp, have brown eyes as youngsters and yellow as adults.

Red-tailed hawks reverse this pattern, with their eyes changing from yellow to brown,

while the yellow eyes of a young Cooper's hawk turn deep red as it reaches maturity.

Okay. young Cooper's hawk turn deep red as it reaches maturity. Not all birds' eyes change color as the bird's age.

But for those whose eye color appears to signal adulthood,

this is likely an adaptation that helps them gauge the maturity and suitability of potential mates.

For Bird Note, I'm Mary McCann.

Bird Note gives you the sounds of birds every day,

and you get the sights as well when you follow us on Instagram.

At Bird Note Radio.