I'm in southeast MO and our birds are probably at an all time low since I've been a turkey hunter (mid 80s). The timber harvest is one factor for sure. It's creating more suitable habitat for predators and taking away habitat from the turkeys.
Fur prices are way down and trapping is a dying art. It's rare to meet anybody who runs a trapline anymore. For the decrease in the turkey population, hunter numbers have remained steady with a small drop in out of state hunters.
For the past 3 years we have had a lot of flooding and thus bad hatches. With close to 4" of rain the past couple of days we are well on our way to another bad year.
Hog populations have exploded in the past 5 years.
Im not sure a single factor is the reason but those I've listed have been big contributors.