If the cygnets are not in the immediate vicinity of the parents, then it usually means that the cygnets either did not survive long after hatching or the eggs never hatched. Sometimes, swans will lay non-viable eggs for whatever reason such as inclement weather, i.e., drought, flooding, lack of food sources, habitat too overrun with other swans and not enough resources, etc. Nature knows when to produce young and when conditions are not conducive for the young to survive. The Regal Swan