I think too there is a lot of reason why numbers are down
but the main one I see in my area, does seem to be food, and I mean food all yr, all the huge area's of blue berry's and wild grapes and other fruits have all but disappeared over the past 15+ yrs.
add in all the houses being built in many prime locations, , in general so many area's of the state here in PA< where timbering hasn't been what it once was, mature forest being the norm, stagnant in new growth,(AKA fresh food, sunlight hitting the soil after leave cover builds)
, and like it or not, the BIG loss of so much farm land, yes Grouse are not farm birds, but many did visit them for easy meals
when I was a kid, all summer long I could go pick black berrys, blue berry's raspberry's, and I mean pick them by the 5 gallon bucket, every day for weeks on end, and sell them, without working too hard to find them
NOW< just finding a few to make a pie or have for a snack, isn't easy, all the old places there GONE from, and most places haven't been developed or anything, just grew up
I think this is a HUGE part of things
as just cause something looks like good cover, doesn't mean it really is healthy and good for wildlife to live 365/24/7
the huge amounts of food, we lost over the yrs is staggering if you look back at what once was there.
I also think the LACK of forest fires is a BIG part of loss of food,.cover and wildlife, again looking back as I was a kid, the local woods caught fire a few times a summer, and they let it burn a lot more before getting it out
NOW a spark flys and everyone with a blue light on there vehicle rushes to the fire as if there is a pot of gold there to steal and need to get to it first LOL
and this is all due to liability and fear of law suits, but all them fires did a ton of good for the forest and the habitat, and in return, the wildlife as well.
Fire is one of the greatest tools we have to help habitat and wildlife, and so seldom used, back yrs ago, controlled burns were VERY common by the game dept, but today there far and few and its all FEAR of being sued if a fire jumps a line
I don't think we will ever see the glory days again of small game, or deer numbers as we did yrs back,
less deer I'm fine with, but were loosing small game big time, minus squirrels and turkeys it seems.
Honesty, I think turkeys are part of the problem, they pick an area SO clean, they leave nothing behind
a success story I think that went too far, as there numbers increased, grouse and other went down if you noticed?