There could be several reasons for just one swan in a pond. The swan could be a swan that has lost its mate. The swan could be a young swan that was chased from the nesting area by his parents because the new nesting season is beginning shortly. Or, it may be that he was blown off course during the migration season. He may be resting to continue on his way once he has rested. If the food, nesting and shelter resources are good in the pond, he may stay.

Once the nesting season begins (February/March/April), he may fly off to find another mate or there may be another swan in the immediate area of other ponds and the two may stay in the pond or go about their way. The Regal Swan