Guarantee they didn’t look in Detroit, Chicago, or Cleveland. They’re filled to the brim.
We had a lot knocked down early due to the late hurricane. Acorns were immature when they fell at that time. What we did get was a bumper crop of baby squirrels in rehab! Good golly...they decided to over-winter the little devils.
Add onto that note, it seemed to me a backyard naturalist that the little furry critters had 3 broods this summer. Which meant things were healthy out there for them, but their over population is what stressed the system. Same with the raccoons in the area, it seemed they had an extra late season brood.