Is the swan nesting? If so, it may not be leaving the nest except for short periods of time. Are you constantly watching the swan, even at night? If not, more than likely it is feeding and drinking while you are not observing. In the heat, if it is not eating or drinking, then it will show signs of lethargy, dehydration, very slow moving and even illness. If the swan is not exhibiting these types of behavior, then it probably is getting the proper nutrition and water and is fine. The Regal swan