yes, i have noticed a difference.
i have 2 private property's that i hunt, they are around 10 miles apart. (southern wv, mingo county)
the smaller of them is a "holler" as we call them. the squirrel there are bold and will bark at you like they want you out, NOW!!! or i will climb down this tree and shove that gun up your... well, you get it.

the larger area is completely surrounded by mountains and much more dense. i saw 5-6 coyote in here a couple days ago. those squirrels do not run out barking, they will all hide at the first twig snap or slightest movement and stay there. the only thing you hear is that low "quick bark" thing they warn the others with. i think they do know...

i haven't seen a red in either for the last 2 years, grey only. and one more thing, these guys don't come out for calls, i tried distress, bark, and one that sounds like a dog toy. nothing... the ones in the smaller property run out mad as hell over a sneeze...

BTW... what part of wv are you in hillbilly???