“Q: Give us a bird fact.”
Avian respiratory systems are absolutely bonkers and allow for unidirectional airflow through the lungs, unlike the bidirectional, terrible mammalian system. A complex series of air sacs holds fresh or spent air, meaning that birds have constant gas exchange even during “exhalation”.
On the first inhalation, air flows into the lungs and posterior airsacs. On the first exhalation, fresh air moves from the posterior air sacs into the lungs. On the second inhalation, the spent air in the lungs moves to the anterior air sacs as the lungs fill again. On the second exhalation, the air in the anterior air sacs is finally exhaled.
It’s all very complicated and ridiculous, as is expected from birds, so here is a handy gif made by Eleanor Lutz:
