Wash duck and pat dry. Score breast and legs by cutting into skin with sharp knife, going 2/3 of the way through the skin, being careful not to slice into meat. Season the cavity and the outside of the duck with garlic powder, onion powder, salt, and pepper; massage spices into meat. Sprinkle caraway seeds over duck, and into scored skin. Place on a rack in a roasting pan, breast side up.
Roast duck in preheated oven for 15 minutes. Turn breast side down, and roast for an additional 15 minutes. Remove duck from the oven; reduce oven temperature to 350 degrees F. Turn duck breast side up again, and return to the oven for 20 minutes. Turn duck one more time, breast side down. Roast for a final 20 minutes. Remove duck from oven and allow to rest for 10 minutes before serving.