What the duck is that?

I was up at San Simeon yesterday and in the lagoon near the campground there was this duck. It was larger and much darker than the mallards with dark legs as well. A hybrid of some sort maybe. I really don't know. What do you think it is? Sorry for the poor quality of picture, I was on the wrong side of the creek and the photo is back lit, so the detail doesn't come through. But you can see the size difference with the mallards and the dark legs.

For more info on oddball and mallard hybrids check out

http://10000birds.com/manky-mallards-domestic-feral-or-just-plain-odd-mallards.htm