Mixed-up Mutant Mallard?

This morning my wife and I were pleased to walk Lake Carneros (Santa Barbara, CA County Park) with Joan Lentz' birding class. Arranged through both Santa Barbara Community College and the Santa Barbara Museum of Natural History, the class is an amusing amalgam of folks interested in learning more about birds - at 8am on a Wednesday!

Following class at Lake Carneros we decided to check one of our favorite spots, the Goleta Slough/Atascadero Creek outlet to the Pacific. Jeanne, the ace-bird-spotter of the two of us, saw an odd black & white bird across the slough-mouth.

While the duck appears to have great affinity for mallards - after all it was hanging with a male mallard and another couple - it sure doesn't look like any mallard I've ever seen.

I'm aware that there are also 'domestic mallards', primarily grown for harvest, yielding 'Peking Duck' among other delicacies. However, I've never seen such a domestic duck either.

And while it doesn't appear to possess the 'warty face' of muscovy ducks, it does seem to have the black & white coloration that I recall from 'back in the day'. Perhaps the above photos will allow for some level of identification among those who are more experienced? Post here if you like.

Oh, Happy Birding!