Regarding the competition between turkey and Ruffed Grouse: In the late 1990’s, a researcher from UW Madison (I believe is name was Scott Lutz) examined this question and found that while there may be the occasional case in which a turkey might opportunistically take a very young grouse chick, the competition between the two species is virtually nonexistent. I’ve seen similar reports out of Tennessee. Additionally, the Ruffed Grouse Society has partnered on numerous studies examining grouse nest predation and have found no evidence of turkey preying on grouse nest.
While the two species will occupy the same landscape, they spend most of their time in different habitats. The grouse is mostly tied to young regenerating (primarily Aspen, but other species as well) forest stands. The turkey is generally associated with more mature forest stands and openings. Grouse and turkey do slightly overlap in feeding habits, but that overlap is considered minor.
One of the big factors in the decrease of grouse in grouse/ woodcock number in northern Wisconsin and the Western UP is that much of the public lands are dominated by national forest (Ottawa, Chequamegon-Nicolet) and those forests are maturing. While I can’t speak on the Cheq-Nic, I can tell you that the Ottawa fell way behind on their allowable cut schedule for Aspen. In fact, so much so that RGS, NWTF, MDNR, and Ottawa formed a partnership to get that timber cut and reverse the habitat degradation negatively impacting the grouse and woodcock populations. Another factor that has the potential to be impacting grouse in northern Wisconsin and the UP is West Nile virus. It is in the area and it does kill grouse.
One final thought, turkey are pretty tough birds, but they are primarily ground feeder. Unless they are being artificially fed, they cannot survive in areas that have more than 10 inches of snow on the ground for over three consecutive weeks. Gogebic County vastly exceeds those parameters.