It sounds like he has turned from Jr. Jekyll to Mr. Hyde which is exactly the behavior experienced during nesting season. The weather seems to be warming a little earlier than usual this year so, the hormones may be working a little sooner than usual. Just give him a couple of weeks to a month to end the mating season, and he'll be just fine. Something may have also scared him such as a boat or person and he is a little edgy at this time. If he continues to be overly responsive, you might want to contact the RSPCA or Wendy Hermon at Swan Lifeline to check-out the situation. The last thing we would want to happen is that he either hurts someone or vice versa trying to protect his family. The Regal Swan