This is Bird Note.

On a hot summer's day, you can watch a bird like a crow very, very carefully and you'll

never see it sweat because birds don't have sweat glands.

Instead, they've evolved a variety of other ways to keep cool.

One of them is panting.

As the bird breathes rapidly, its throat quivering, heat is carried out of the body via the lungs

in air sacs.

The lungs are a one-way system, so cool air coming in does not get mixed up with warm air

coming out.

Holding its bill open, the bird also oscillates a tiny bone in a part of its throat where

there are a lot of blood vessels.

The oscillations bring more blood to the area, allowing heat from the blood to dissipate.

Bear skin on the legs, face and beak also help the cooling.

So do puffing out feathers, fluttering wings or splashing in a puddle or bird bat.

And soaring birds, like hawks, can simply ride the updrafts far above the ground to where

the air is cooler.

If they're closer to the ground, birds can also do what we do to avoid overheating.

Keep busy during cooler hours and take it easy in the shade as the day heats up.

For Bird Note, I'm Mary McCann.