Breathe in, breathe out

Hi everyone, I’m Claire from the Bird Team! Since this is my first Keeper Stories Blog, I thought I’d talk about my favorite subject to teach about birds: Breathing! For us, breathing is a bidirectional flow. We breathe in, air goes to our lungs, we breathe out, and the air leaves our lungs. This means that the “new” air we breathe in will mix with the “old” air we breathe out, resulting in “mixed” air that has less oxygen.

Birds have a more efficient way to get oxygen to their lungs and into their bloodstream. It’s called unidirectional breathing! In addition to lungs, birds have air sacs: some in the front (anterior) and some in the back (posterior). With these air sacs and unidirectional breathing, birds are able to have a constant supply of fresh, oxygen-rich air in their lungs. Birds have this system for a reason. Flight takes a lot of energy! They need lots of oxygen-rich blood to power their muscles so that they can fly.

Here’s how it works: on the first inhalation, air will move from the trachea to the posterior air sacs. On the first exhalation, that air in the rear air sacs will move to the lungs, where the oxygen can diffuse into the bloodstream. On the second inhalation, the air in the lungs moves to the anterior air sacs. (At the same time, fresh air is also being moved to the posterior air sacs!) Lastly, the second exhalation sends the air in the front air sacs back into the trachea and out. Since the “first” and “second” inhalations and exhalations are technically happening at the same time, air is cycled between the sets of air sacs and the lungs, creating a constant supply of fresh air for the lungs without mixing the old and new air.

All that fresh, oxygen-rich blood makes for strong muscles to take to the sky. Bird respiration is one of my favorite topics, so I hope you learned something new. Thanks for reading!

Claire S.
Keeper I, Birds