I fix them just like any other duck which is usually using the following recipe:
From "A Taste of the Wild" by A. J. McClane
In my opinion, one the best of all wild duck preparations is not only simple but guaranteed to be delicious. A wild duck is virtually al breast; the diminutive legs and wings provide more sinew than meat, and there is hardly any sizable part elsewhere on these fowl. I don't even pluck the birds but simply skin the breasts out (at the midline from the apex of the breastbone with the point of a knife) and excise the meat, which can them be cut lengthwise into 2 fillets. Allowing a pair of fillets for each of 4 people, I marinate the duck for about 30 minutes in 1 cup of olive oil, the juice of 1 lemon or lime, and 2 tablespoons of soy sauce and cook over a hot charcoal fire--about 4 to 5 minutes on each side or to an internal temperature of 120 degrees F for very rare or 140 degrees F for medium-rare. Optionally, the breast meat can be sauteed either in fillet form or as a scaloppine, by gently pounding with the flat side of a chef's knife. For the saute pan the duck can be marinated in vermouth or white wine, then ducted with seasoned flour and cooked in clarified butter over medium heat. Deglaze the pan with vermouth or wine and spoon over the fillets. Either way the result is comparable to prime filet mignon in texture and, if anything, more flavorsome. Accompanied by wild rice, watercress salad, and a currant or gooseberry preserve, it makes a superlative meal. The remaining carcasses, incidentally, need not be wasted as the can be simmered and added to your game stock inventory in the freezer--or made into a soup.