physical adaptation to one’s environment is nothing new.
I wish the wild turkeys around here were bigger but the hills are pretty lean pickings on this side of the valley.
Based on 100 years of photographic evidence - it is very clear that (Western) humans have increased in volume. We are now enormous - up down and all around.
Humans live 70+ years. We changed in just four generations.
Birds live 2-5 years - Avian generational change has taken much longer. It may be cyclical - they get big & get smaller or cross breed or become extinct. Didn’t Darwin explain that?