We would strongly suggest that you capture Carl and place him indoors. In the meantime, take a net and pretend to try and capture the other two swans. If you harrass them enough, they should leave the area. If you can at least capture one of the swans, just long enough so that it knows you can get to it especially near your dock at night or early morning, they will probably leave the area. No swan wants the possibility of being captured by anyone. Please let us know that you captured Carl and he is safely in your home. The Regal Swan