Gumbo or casserole is a good use for them. I grew up eating bluebills, ringnecks, and buffies at least once a week. Would I roast a diver instead of a mallard? Probably not but more on that later . . .
Gumbo: four parts flour, three parts oil (try 1 cup flour and 3/4 cup oil) cook and stir over medium heat until you get a nice brown color (think dead oak leaves). Take half the roux and put it in a stock pot, add one diced onion, two diced green peppers, three diced celery stalks, a bay leaf, and a pinch of cayenne. Stir and cook over medium heat until the aroma starts to hit your nose (five minutes or so), add 1 lb smoked sausage and two cut up medium divers or three buffies (legs and thighs in one piece, wings and backs split,, cut up breasts, and any necks and giblets you saved) Cook and stir for five to ten minutes until everything is coated in roux and the sausage begins to smell. Toss in three chopped garlic cloves and then add six cups of water and a 1/4 cup red wine. Reduce to low and simmer for 1 1/2 hours until thickened. If you want to splurge, toss in some peeled shrimp and let simmer for 15 more minutes. Serve over rice . . . Good stuff.
Casserole: Rub quartered birds with SPG (salt, pepper, and a cut garlic clove), brown in unsalted butter or olive oil. Put the birds in a 9x13 baking dish along with a diced onion, one stalk of diced celery, a bay leaf, a small can of slice water chestnuts, and, if you want a 1/2 cup of slice fresh mushrooms. Add 1 cup of white rice and 1/2 cup red wine, and 1 1/2 cups of water. Cover with foil and bake at 325 for 1 1/2 to 2 hours until the liquid is absorbed and rice is tender.
Roasting? Well, maybe a redhead or can but Ted Nugents cook book has a recipe that I have used successfully (i.e tasty) on late season buffies. Take a dressed bird (actually three for a family meal), Rub inside and out with Lawry's season salt and refrigerate over night in a ziploc bag. Oil a roasting pan and then sprinkle the birds with lemon pepper, put slices of apple and onion in each bird, and more quartered apples and onions, and cut up carrots in the pan. Add 1/2 cup of wine and 1/2 cup of chicken stock to the pan. Put a slice of bacon on each bird, cover the pan and bake at 425 for 1 1/2 -2 hours (Ted says three but that may dry out the birds), basting every twenty minutes with the liquid. Tasty!