Some years ago, I was running a wave bar in a glider at c. 12,000' in the middle of Wales, above 7-8/8 cloud and I met a small squadron of geese doing the same thing only in the opposite direction. They were right in the best bit of the lift and going for it, wings locked, staggered formation and beaks in raised mode. These guys knew all about TAS, wind components and energy conservation... :)

It's odd that although birds are todays version of dinosaurs, they are better evolved than us in some areas. Their eyes have the blood vessels on the outside unlike us (I don't think therefore they have a blindspot), they have more types of colour receptors, and their lungs are different - allowing them to happily fly at 30,000+ feet. They also appear to be able to fly in IFR - well, apart from the aspect of bumping into tall obstructions.

Many years ago Boeing Airliner had an article about other animal strikes in flight (wish I had kept it). It included things like rats snakes and fish! Many of which were probably dropped by a smart bird seeing an approaching aircraft and taking the sensible option.

Clark Y

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. http://home.infionline.net/~pickyperkins/pi.gif

The birds sleep by closing down one side of their brain - http://news.nationalgeographic.com/news/2007/09/070913-longest-flight.html
the nav equipment is pretty good too.

High Altitude Bird Strike
 

In the 60's, I was in 707 school in Miami for upgrade. The discussion one day was why we switched the window heat switches from high to low above 10,000 ft. The instructor mentioned that there weren't any birds above 10,000 ft, so the extra heat was unneeded. A classmember named Phil, a passonate bird watcher, interrupted the instructor with his dialog about the number and size of birds that routinely fly above 10,000 ft....including the eagle, giant condor, geese, vultures...his list was endless. The bird lesson rambled on while most of us went to sleep or doodled. The senior Captain in the Class, John Clower, finally interrupted Phil to relate his experience with giant birds. His comment was that he had read just the other day the NOTAM that warned to look out for a 40' crane at the end of 9L in Miami. That ended the bird watching discussion.:)

Thanks PETTIFOGGER, interesting article on the bar-tailed godwit.

I see that the flight averaged 34.8 mph and took 8.5 days non-stop at elevations between 3,000 m (9,843 ft) and 4,000 m (13,123 ft), where the temperature would have been between 30ºF (-1ºC) and 12ºF (-11ºC), and that the bird carried a satellite transmitter and batteries lasting the return journey!

So not so cold, but still pretty chilly for both the bird and the batteries, being cold-soaked for 8+ days. http://home.infionline.net/~pickyperkins/pi.gif