As long as the parents do not go too far out of range, they should go back to find the other cygnets, especially if they hear the young swans crying. If you find the cygnets, you might try to find the parents and reunite them. However, if this does not work, you may need to find a wildlife or waterfowl facility to raise them. You also need to make sure that these cygnets are reunited with their parents as other swans will kill them. If you find the cygnets, then take them to where the parents can see and hear them cry. If the parents come running towards you, place the cygnets in the water and they will swim towards the parents. Please let us know how this works out. The Regal Swan