pgbnh wrote:
I am clearly no expert on bird physiology, but what the heck is a bird
breathing at 38,000msl????

Just because he's there doesn't mean he meant to be.

I'm guessing that if a bird gets caught up in some lee wave lift (which
can exceed 50k) he might just climb and die from hypoxia or temperature.
as in 'bird brain'. Pure conjecture though.