The record for the highest-flying bird was set when:
A) A vulture was sucked into a jet engine at 11,550 m (37,900 ft.) ü B) Geese were seen above Mt. Everest at over 8,840 m (29,000 ft.) C) A duck collided with an airplane at 6,400 m (21,000 ft.) D) A black-poll warbler flock was observed at 4,880 m (16,000 ft.)
In 1973, a Rueppell’s griffon vulture was flying high above the Ivory Coast of Africa when it met its end in a jet engine. No one knows what it was doing up so high, since vultures normally cruise at 2,000 feet. Bar-headed geese migrate over the Himalayas, so they are the most regular high-flyers. Smaller migrating birds have been tracked on radar as high as 21,000 feet. Oxygen levels are much lower at high altitudes, but birds have evolved to cope with low oxygen levels by using air sacs as well as lungs. Air flows into the lungs and out the air sacs, so that fresh air drawn into the lungs isn’t mixed with “stale” air, which keeps the oxygen content as high as possible.
