No, there is no swan repellent. Obviously, the swans allow humans other than males. This would seem to indicate that a male did something bad to the swan, such as kicking, chasing or just being mean to the swan. Is there room enough to place a small fence between the swans' habitat to leave just enough room for them to get out of the water, but not engage people?

You might try to desensitize the swan by having an unafraid male approach the swan to feed it bread. If the swan tries to bite or attack, open a white umbrella (without the spike at the top of the umbrella/you need to have a flat top to the umbrella). The umbrella will give the appearance of a larger swan. If you can safely grab the swan, gently to hold its neck and keep it from swinging with its wings, keep the swan calm. Sit by the swan, talking to it and letting it know that it cannot escape. Hold the swan on the ground for approximately 4-5 minutes. Then, let the swan go. He may try to come back at you and if it does, open the umbrella and try to capture him once again. A couple of times letting him know that he can be captured and held will usually keep him at a distance from humans. Good luck. The Regal Swan