I restrain my cat and yell at the ducks to go away because Feetz will think they are cat toys and can be rather rough. He won't eat them, since he's always been fed wet food, but the last time he found a mouse, he played with it until I found parts all over the basement. He didn't eat any of it. He was just... enthusiastic. I first knew he found a mouse when I found its head on my pillow.
That's basically a Kitty Hallmark card.
I fear these poor ducks are not up to the enthusiasm of my cat. Nor do I want to do to bed and find my pillowcase stuffed full of duck heads. So, I will simply shoo them away in the hopes they are quick on their feet.