This is really, really cool! AND published in the journal Nature!
“Another open question is how the birds know to fly in these optimal spots. Dr. Usher said that they might have evolved “rules of thumb” for flying, or that “they have good sensors” and adjust to find spots that feel good.”I’m betting on the latter. When you walk or run along non-uniform terrain, you automatically adjust stride and position; it seems to follow that birds would do something similar as they fly.