If it is leaving the water and reluctant to get back in, it means that it is being chased by something, either a predator or an older swan(s). If it is a juvenile, then the parents are forcing it to leave the area and find another habitat. It could even be a juvenile from another area that was displaced into another swan's area. We would suggest that you contact RSPCA immediately, and have them come out and rescue the swan to see if everything is okay. If it is, they may release it in the area so that it can continue on its way. If you live near Windsor/Datchet area, you can contact Wendy Hermon at Swan Support. Both of these rescue groups will come out and check the swan. The swan may be taken to a rehab center, checked out for a couple of days and then returned back to the area. If it is a juvenile, it will be placed with other juveniles. The Regal Swan