Ducks may take a look, but as stated in Oldtimr's post, if they don't see what's making the noise, they likely won't do much more than buzz the tower.

However, Oldtimr is correct again.. the opposite is true...ducks are more apt to come into decoys with no calls present. As a matter of fact, I've had plenty of instances where greenheads have worked my decoys, come in fast and hard with their landing gear down and I never blew one quack to get em there.

Your chances are much better with decoys present, even if it's just a dozen. If I had to make a choice, I'd rather hunt with decoys and no call, rather than a call and no decoys.