It seems that after 2 straight days of hunting they learn i'm in the woods
my guess is they can learn anything that would assist in Woods 3 keys to survival.
But I dont think they watch the skies looking where the birds are flying. My guess is they smell where the foodpile is.
We all know by now how amazing a deer olfactory system is, so its not hard pressed to me to imagine they can smell the stuff from far away.
Here is something I witnessed 3 days ago:
My daughter and her friend went to the side and backyard and planted seeds. TINY
herb seeds (like basil, parsely etc).
Next day, squirrels dug them all up!! It took no time for them to find such a miniscule food source, I would imagine its not any more difficult for a deer to find a fod pile.