I carry a bit of olive oil and a ziplock with some salt, pepper, garlic powder and whatever else I might throw in. Breast the meat out rub with olive oil and seasoning and then cook it over an open fire either on a stick or my ruta locura titanium grill/grate.
Never crossed my mind but sorta obvious now... Do you toss it on a bed of coal (and for how long) or cook it a bit indirect? Sounds like a solid solution to cooking them on the ridge.
I do the feet-pull cleaning method, then pull the guts out. Lay a strip of bacon over the breast and make a little taco out of foil. I lay the foil right on some coals, on the wood stove, or in a pot/skillet on the backpacking stove.
Spruce/ruffed grouse and ptarmigan are really lean and dry out. The pork fat helps tremendously, although I've used a liberal amount of vegetable oil on occasion when it's all I had with me. Not sure about other species of upland bird, as I've only ever hunted them in Alaska.
I quick cook the meat in a pan with water. As it cooks I start shredding with a spork and set aside. I'll then use that water to cook some rice, typically the mexican flavored rice. Once the rice is done I mix it all up and enjoy.