No, he cannot go onto a pond, and even then, a very protected pond until he is approximately 6-7 months of age. Because his mother abandoned him, and probably knew something was wrong with him, he never learned how to be a swan, recognize and evade predators. So, he is going to need loads of attention for the next few months and then, protection from predators, wild or domestic and even other humans because he is going to be too trusting.

He needs to be raised in a protective setting with other waterfowl, i.e., Swans, geese, ducks etc. You need to see if you can get him to a wildlife rehabilitation facility, zoo or poultry farm so they can properly care for him for the next several months. We would be cautious in questioning whether he even may survive that long with a balance problem. This could be a neurological issue caused by some type of infection or injury which is another reason he needs to be examined and possibly treated by a veterinarian or wildlife rehabilitation specialist. See if you can contact the park and see if they know of a wildlife rehabilitation center and veterinarian that can diagnose, treat and raise him with other waterfowl so that he can be to released onto the park pond in 8 months or so. The Regal Swan