Combine first 6 ingredients for stuffing. Stir well, and set aside.
Remove giblets and neck from ducklings; reserve for other uses. Rinse ducklings thoroughly with cold water; pat dry. Prick fatty areas of ducklings with a fork at intervals. (Do not prick breast.) Stuff dressing into cavity of ducklings. Close cavity with skewers; truss. Lift wingtips up and over back, tucking under bird securely. Fold neck skin under, and place ducklings, breast side up, in a roasting pan. Cover lightly with aluminum foil.
Combine flour and orange juice; mix well. Bake ducklings at 350° for 2 hours and 15 minutes, basting frequently with orange juice mixture.