Animals and birds do not mourn at the detriment of their health or that of their family. He may be looking for her for a couple of days, but not to the extent of starving. He may be hungry because the time of the season is dictating food resources, i.e., drought, flood, explosion of alage, etc.

If a fox is in the area, it will come back for him or any other swan. The fox probably got the cygnets or the eggs if the eggs had not hatched. To feed him in this overgrown area, is going to encourage him to stick around. That is probably not a good thing because you don't want him trying to come up for an expected food treat only to be eaten by an awaiting predator. The best thing for him is to get him back to the public park with the other swans so they can look out for each other. As long as there are not huge territorial issues, most public park swans will tolerate other swans in the area.

Bread is not a great food source because it serves no nutritional or filling value. The best food is poultry layer pellets mixed with cracked corn with a treat of lettuce. Swans in the wild eat aquatic vegetation from the much. They may inadvertantly receive fish larvae, frogs, insects, etc., mixed in with the vegetations, but they are mainly a grazing bird.

Again, this may not be the ideal situation to be feeding him so that he can go on about his business and try to find a new mate if he so desires. Usually, male swans will not re-pair if they lose their original mate. But, they will continue to go about their business, eating, preening, bathing and being a swan. The Regal Swan