Shotgun you must know little about ducks. When mallards sold for 25 cents, canvasbacks sold for ten times that. Divers like cans, redheads, ringnecks, and scaup do not eat fish. And they don't eat corn out of cowshit like mallards do. Goldeneyes and large mergansers do eat minnows and small fish. I would not trade a fat roast canvasback for a season's worth of mallards. I bake ducks with nothing in them at 275F for a long time...four hours for a big canvasback. No seasonings to ruin that nutlike flavor!
When cleaning ducks, slit skin around neck, down both sides of the backbone, then down in front of the anus, but behind the legs. Then shear through down both sides of the backbone and around both sides of the synsacrum and pull head, backbone, lungs,intestines, and rear end of duck out as a unit. Virtually blood and odor free and no cut intestines. When cooking, fold the legs inside the body cavity so they do not dry out during cooking.
