We had 2 swans that always swam together and another that tagged along. Then the next year there were only 2 so we figured the 3rd one was their baby and found a mate...wishful thinking I suppose. Well for the last 2 years there's only been 1 swan. I feel so bad for him/her however yesterday another swan came!!! We were so excited but the old swan is chasing it...like all day!!!...with the wings up. Is this some kind of type of mating dance? or is it really trying to run it off?