Can anyone please tell me what model duck this is? It has been hanging around my pond all alone for the past few days. I scoured a couple of duck ID sites to no avail. I'm beginning to wonder if it's a domesticated hybrid of some sort because it doesn't seem to be as paranoid as a wild duck, and it's rather large. It keeps its distance from me, but it doesn't freak out and take off like a wild duck normally would.

When it flaps its wings they appear to be predominately white, and the dark colored feathers look to be either black or green, depending on the light.