I know little about the temperment of Swans but I do know I have seen them on ponds and lakes together.I am seriously thinking about getting swans next year, but have to make sure they get along with geese in a free range situation, i have several ponds one is very deep the other two are just big duck ponds wher the deepest part is 5 foot and a foot at the shallow part.
My geese never swim in the deep pond but are always by the big duck pond and the dry creek i keep a hose tricking in.
If Swans prefer a deep pond pretty much to them selves then i will be good to go i just don't need a pair of swans that try to pull ranks around here LOL