Hi Sean,
do you have any further description of your mystery bird?
We found a bobwhite in central Maine, years ago, and there is a hunting season for them in Maine, so folks are still raising and releasing them.
I was once surprised by guinea fowl in high grass. They turned out to have wandered from a nearby farm.
Besides pheasant, bobwhite and chukar, do folks know any other bird species raised for hunting in Maine?
Hope to hear your mystery bird solution!