Let's face it--when it comes to dealing with winter, most birds seem an awful lot smarter than humans. Instead of griping about the weather, they simply head for a warmer climate. There are also humans that try to migrate, but running from yourself, that’s mighty far to run. Where ever you go, there you are.
Why migrate? Because it gets boring shivering in the dark. And because it's bleak in the winter. And because there's nothing to eat. And because the ancestors did it.
Birds can fly higher than Mt. Everest. Bar-headed geese have been recorded flying across the Himalayas. (Note: birds don't fly this high just to get in the Guinness Book of Records, but rather to reach their destinations efficiently. From radar studies, scientists know that birds can change altitudes to find the best wind conditions. To fight a headwind, most birds stay low, where ridges, trees and buildings slow the wind. To ride a tailwind, they get up high where the wind is as fast as possible.)
How high can we fly?