Preheat oven to 300°F. Wash the duck as little as possible. Just clean inside and outside with a moist cloth. Salt well inside and outside.
Peel quinces and cut into segments. Stuff them into the cavity of the duck.
Place duck in a roasting pan and pour melted butter over the bird. Roast in the preheated oven for about 10 minutes.
Pour the wine on top of the duck and put it back in the oven. Continue to roast the duck, basting all the time with the butter and wine in the pan, until it is almost done. This will be 1 hour, or less.
Increase oven heat to 500°F. and roast for 3 or 4 minutes longer, until skin is crisp.
Total roasting time for a young wild duck depends on how bloody you like it. In Hungary they prefer it well cooked. Serve with a risotto made with the giblets of the bird, and with braised red cabbage.