In the past I have documented the presence of a few black-and-white hybrid ducks that are part of a large flock of Mallards in a park by my house. We also have seen the occasional domesticated Pekin duck floating along the local creek, and it appears that these white ducks have produced some hybrid offspring.
The female Mallard-Pekin hybrid in the photograph happened to be resting near another Mallard female, so you can see the differences as a result of the hybrid process. The hallmark wing band on the female Mallard remains in the hybrid, though the color of the banding changed from a metallic blue to brown. The head and bill coloring of the hybrid seem similar to the female Mallard, though the rear half of the bird is mostly white.
Their appetites are about the same, though.