We believe a couple of things are occurring. First, these ducks came after the swans had established a territory, so this may be the reason that the swan picks on these three instead of the other duck residents that you had prior to the swans' arrival.

Second, the swan is picking on the white duck more than the other colored ducks because the swans seem to pick out the color white more readily. The reason is that this possibly signals rivalry of territory between other swans. Because the muscovies are a larger duck than most duck breeds, the swan may be thinking that this is a rival swan, even though it is smaller.

The reason we believe that the color white is the trigger is that the swans raise their cygnets until they are approxiately 8-12 months of age. Once the cygnets turn from the taupe color to white, the parents start to chase them from the habitat, again signaling future rivals for mating and habitat sharing. In most instances, the birds will leave waterfowl of brown or other colors alone.

We would suggest that you keep the muscovies on a separate pond or habitat if possible to keep them from incurring serious harm. The male swan will kill them if given the chance. Is there a possibility that you could fence in part of the pond/habitat to give the muscovies an area to themselves without intervention from Mr. Swan? The Regal Swan