I don't think ducks can smell good enough to detect human odor but I believe they can smell food, especially in the water. I wouldn't be surprised if the stuff worked.

I've got a pond that I plant something in every year and this year I'm doing japanese millit again. I planted the muddy areas about a week ago and this past thursday I threw some seed in the water just to see if it would come up. By the next morning there was 15 woodducks on it.