Well poop I thought I come up with that on my own... I started whistling at them when they first started roaming the yard whenever they would go where I didn't want them and I would go shoo them back to safety. I was just thinking what a mamma duck would do ha ha It did seem to work for a while but they are pretty independent of me now. What's awesome for now is I have two purple Martin houses one on each back corner of my back yard. So when the ducks get too close to the back fence the martins swoop around and they come running back lol that's teaching them to stay close!!
Whistle when the Martins swoop over, and only then for a bit.. then you can use the whistle for calling them back and it will work better... just don't overuse it and keep up on whistling when they freak out... that's the key...