There may be something wrong with the swan especially if whatever it swallowed will not digest. We would strongly urge you to contact Wendy Hermon at the Swan Lifeline Rescue Center in Eton. Even if it is a wild chase, at least the swan will have been examined to make sure that he/she is okay. If everything works out, it may be that the swan is being chased from the area by another territorial swan and the "depressed" swan will have to find another area. Let's hope he is not sick. Please let us know how this ends. The Regal Swan