Ugly bird at Toogood pond

We went to Toogood pond last evening, and saw the ugly bird again. This time, the bird joined a group of Canadian goose families. So it did not look that lonely as last time.

I was trying to figure out what species is the bird, but failed. It is a black bird with some white blocks, the size of a Canadian goose but much fatter. I doubt it could fly with the weight. The head looks like a turkey, but with its webbed feet, it shouldn’t be. When we approached it, the ugly bird started to drag it body towards us, wagging its fat tail like a dog.