it is going to depend partially on where you hunt.... I often use certain goose decoys, particularly snow and specklebelly (white fronted), to keep ducks from working over a certain area.... while they will often land near goose decoys in the water they will rarely land among them (remembering ducks oftenlike to land in open pockets rather than in between decoys).... all that being said, if I were planning on hunting ducks I would carry at least 1/2-1 dozen duck decoys.... they don't have to be the best in the world just hold the ducks attention while they are working.....