While shooting some Wood Ducks at Yorba Regional Park(2 smallish lakes) in So Cal. I am pretty sure this is a domestic.....:D. There is a wild one that is similar, Swan Goose. There are two domestic types that have came from it...The Brown Chinese and the African. My gut feeling is that it is the African.
I had researched it some before I posted. I had also seen the URL John sent(It is a pretty good one). As I see it the Swan Goose is mainly in Asia and is an endangered spcies. So I doubted it was one of those. The African and the Chinese are both domestic geese that much of there make-up is from the Swan Goose. I aslo read that the African has nothing to do with being from Africa. I still kind of feel it is an African type. I also think there is a Chinese Brown type.
Yes they can be aggressive. I had a 2 female and one male White Chinese several years ago that we used as guard animals. They worked very well at their job.