Darwin would say the ones that didn't thermal too well didn't
survive, didn't reproduce, and simply missed out on some good
airtime for generations to follow. The birds that acquired the
insight to locate updrafts gained the same advantage we seek: xc
distance. Soaring birds are usually larger than others, maybe good
thermaling skills means better meals. They still need to survive
winters with fewer, weaker thermals by other means.

gill
www.gillcouto.com


Uri Saovray wrote:
Does anyone have an idea of how the birds know where to thermal? Do
they have a vario? Where is it? Where is its capacity?
Assuming they breath while thermalling, then I doubt they use their
lungs as capacity... or maybe they stop and sense the air coming out
their noses.
Just wondering...

Uri 4XGJC