On a hot summer’s day, watch a bird such as a crow — or this Purple Martin — very carefully. You’ll never see them sweat, because birds don’t have sweat glands. So how do they keep cool? One way is panting. As the bird breathes rapidly, heat is carried out of its body through the lungs and air sacs. Bare skin on the legs, face, and beak also help with cooling. So do puffing out feathers, fluttering wings, or splashing in a puddle or birdbath. And soaring birds like hawks can simply ride the updrafts far above ground to cooler air.
How Birds Stay Cool
Written by Bob Sundstrom
This is BirdNote.
[Music – Béla Fleck ‘Flight of the Cosmic Hippo’]
On a hot summer’s day, you can watch a bird like a crow very, very carefully. And you’ll never see it sweat. [Call of the American Crow http://macaulaylibrary.org/audio/58186]
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’s carried out of its body via the lungs and air sacs. The lungs are a one-way system, so cool air coming in doesn’t 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.
Bare skin on the legs, face, and beak also help the cooling. So do puffing out feathers, fluttering wings, or splashing in a puddle or birdbath. [Music break]
And soaring birds like hawks can simply ride the updrafts far above ground, to where the air is cooler. 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 BirdNote, I’m Mary McCann.
[Music – Béla Fleck ‘Flight of the cosmic Hippo’]
Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. American Crow call  recorded by William W H Gunn on August 13th 1957.
‘Flight of the Cosmic Hippo’ by Béla Fleck performed by Béla Fleck and the Flecktones from the 1991 Warner Bros album ‘Flight of the Cosmic Hippo’
BirdNote’s theme music was composed and played by Nancy Rumbel and John Kessler
Producer: John Kessler
Executive Producer: Dominic Black
© 2015 Tune In to Nature.org August 2017 Narrator: Mary McCann
ID #: summer-02-2015-08-03summer-02