Rinse the ducks and pat dry, then par-boil them in a large saucepan, and drain. Sprinkle with salt to taste.
Combine the butter, juices, chopped onion, tabasco sauce, Worcestershire sauce, garlic salt, and pepper to taste, mixing well.
Fill the ducks' cavities with the quartered onions and potatoes. Make a slit in each side of each breast.
Place on rack in roasting pan and brush each with the butter sauce. Cover loosely with foil and bake in a 375F oven for 1+ hours or until tender, basting with sauce every 10 to 15 min.
Remove the foil and bake an additional 20 min. or longer until browned.