Using a wire whisk, combine the marinade ingredients in a stainless steel bowl. Add the quail and rub thoroughly with the marinade, inside and out. (Don't be afraid to use your hands.) Cover the bowl and refrigerate for several hours or overnight.
The Port Sauce with which the quail will be served may be made while the quail is marinating. Combine the bones, vegetables, and seasonings in a roasting pan and roast in a 375 degrees oven for 2 hours, turning occasionally, until everything is well browned. Transfer the bones and vegetables to a heavy bottomed stock pot and cover with the water. Bring to a boil, add the veal stock or beef broth, lower the heat to a simmer, and cook 1 1/2 hours. Strain this rich stock into another sauce pan, add the cup of port, and simmer again to the reduce liquid to 11/2 cups. At this point, the sauce may be cooled and refrigerated for up to two days. Rewarm the sauce during the quail's preparation and add the final enrichment of port and butter just prior to serving. This will both enhance the final flavor and give the sauce a silken sheen.
To cook the quail, preheat the oven to 350 degrees. Heat 2 tablespoons of olive oil in a cast iron or other heavy bottomed, ovenproof skillet over medium heat. Drain the quail of excess marinade and pan roast, uncovered, until mahogany in color (about 3 minutes on each side). Place the ovenproof skillet and quail in the oven for 9 minutes. Serve immediately with the port sauce.