its a hybrid of some sort, and not an easy one, at least for me.
But I give it a try and hope for Jörn and others to jump in:
Bill says its a Common Pochard or one of the Wigeon species. One the first picture, I see a dark area on the culmen and a still paler area near the "inked" black tip (which is slightly diagonal) Therefore, I mute a Common Pochard as one of the parents
What else do I see: a peaked crown, a head pattern resembling a female-type Red-crested Pochard, a gut/jizz feeling of a Wood/Mandarin Duck...
But I see I change into speculation-modus here and I better stop and hope for others to jump in
I must admit when I first saw it I was thinking it was an escaped exotic but couldn't put a name to it so I wonder if it is a hybrid escaped from a collection which would widen the pool of potential species.