In article 40ee83d7@
Bird fight is not like our flight where what we're doing is totally
alien and has to be (mostly) a conscious process. Birds fly quite
UNconsciously. What they see is "integrated" with what they feel in
their muscles. There is no separate process for "I am entering a
thermal" which is different from "I am in a steady climb". It's all one.

They measure altitude with their eyes as Bill Daniels said. They
'recalibrate' their gyros continuously by looking around. They're not
much better at raw data IMC than we are and lose their 'calibration'
quite quickly in cloud.

Are you sure about this? I have seen birds flying in cloud quite
successfully.

Many of the ideas are interesting but I'm with Occam's Razor. Birds fly
like we walk - by looking around to 'calibrate' the inner ear balance
mechanism and feedback from muscles. I can't see a real need for any
other unique mechanism.

... until we get to intercontinental migration.

GC


--
Mike Lindsay