That is not the greatest area for partridge,IMO. Further north is The Manistee National Forest which has better habitat for forest birds. If you have the time, I would recommend scouting above Michigan Route 55, on state lands between Cadillac and Petoskey. Generally the further north towards Petoskey you go, the better, but you will need to do your homework.

If you want to PM me, I can be more specific.