The new swan is probably from someone's personal collection and was not pinioned or clipped (against state law) and allowed to fly away. You can probably encourage him to stay by offering him plenty of food, lettuce, cracked corn/poultry layer pellets and bread. If you can eventually catch him, you need to get his wings clipped so that he can remain on your lake.

Hopefully, you do not have any alligators which otherwise, will mean a very quick demise for him. If he continues flying from pond to pond, this will probably be his fate, as most all ponds or lakes in Florida have alligators. Because swans are not used to alligators, they may not fear or sense the danger, therefore, not avoiding or fleeing from the alligators. The Regal Swan