Morgans wrote:

Birds have a neat thing going on with their lungs. While we take in fresh
air, the oxy gets taken up while the co2 gets taken out of the blood, then
we exhale. Not much exchanging goes on as we exhale. Birds don't waste that
portion of time we spend exhaling, but instead have more air being pumped
across the membranes from reserve sacs. It is almost a circular motion type
of breathing, with the possibility of almost double exchange compared to us.
I'm quite sure I don't explain it well, as it is tough to comprehend.

I think you did very well. Sounds almost as good as if they had two separate
lung systems. Sounds to me sort of like a bagpipe; the lungs keep the sacs full,
and they get a constant flow of oxygen from the sacs.

George Patterson
Drink is the curse of the land. It makes you quarrel with your neighbor.
It makes you shoot at your landlord. And it makes you miss him.