I remember reading a story about a woman who lived on the water in England, and there was a local swan known for attacking boats. One day they held some sort of boating event on the river, and the swan went ballistic chasing boats all day. But the swan in question also had cygnets, so he herded them all to the woman’s waterfront deck where she could watch them, chased the boats until he was exhausted, and then collapsed on her deck for a long nap.
Swans are just very particular about what they like, I suppose.