We've seen it 2 times now, a display by 2 what we assume are male swans. They turn opposite to each other, in circles, meeting face to face and round and round. Other choice is it could be a mating thing. In any case, it appears almost like a dance or Olympic synchronized water activity. In the most recent performance we were privy to, at Cranberry Marsh, the 2 swans jumped at each other before breaking up and one flying off. This is what leads us to the conclusion that it is 2 males trying to show dominance and drive the loser away. I'd have to Google it though, to be sure I guess.......which I haven't lol!
Not only were the Swans at it, we had the privilege of watching not to mention hearing Terns fighting and chasing each other, often when one has food and the others don't. Then there were the gulls, doing the same thing but less relentlessly. Swallows were also at it, presumably telling each other off lol! Spring is always a great time for funny animal and bird behaviour.