He may not be around the times that you are checking. Early on, the female will leave the nest to bathe and feed. Some males will sit by the nest while others will patrol large areas of the habitat. When the female needs to take a break, he will return to sit on or near the nest. If you do not see him in the next few days it could mean that something happened to him or he found another mate. And, yes this can happen depending upon the individual bird. You might check with your local RSPCA or Swan Lifeline in Eton to see if they have had any reports of rescues in your area. The Regal Swan