The worst thing to do would be to offer him something else that might get caught in his throat if there is already something present. We would strongly suggest that you capture him and get him to an avian/waterfowl veterinarian ASAP. To delay, may cause him to die. The stress of being captured is minimal in a case like this. Capture, examination and treatment by a veterinarian is of the utmost importance. He may have a fish hook or fishing line or other obstruction that can kill him lodged in his throat. A veterinarian canreadily find and treat this and allow your swan to continue to live a full life. The Regal Swan