I am curious how these birds keep warm at, say, 32,000 ft where the ICAO Standard Temperature is -57.8ºF (about -50ºC).
If their eyes are open, wouldn't they freeze solid?
If they keep their eyes closed maybe they don't care whether it is day or night.
There was a short item this week on US TV about a bird which has just been tracked flying non-stop from Alaska to New Zealand, a distance of 7,250 miles. I was curious about how long that flight took.
If we assume that it flew at an altitude of 10,000 meters (32, 808 ft) and at an indicated air speed of 30 mph, its TAS would be about 51.7 mph.
This flight was north to south, so not much aid from Jet Streams, but maybe as much as another 50 mph from trade or other winds.
So at a ground speed 100 mph (at the most) this flight would have taken at least 7,250/100 = 72.5 hrs = 3 days in the air.
What with keeping their eyes shut to stop them freezing, and their brains in a deep freeze for 3 days, I wonder (seriously) whether these birds fly in their sleep. Maybe they don’t even remember the flight.
