More than likely the young birds flew away to join their parents, and other swans for the winter migration. The parents, while teaching the cygnets to fly, also show them their habitat as well as area markers to recognize how to leave for other areas and return to their home areas. Migration would have been another important lesson. When large flocks of birds leave for the winter, they make a lot of noise and communicate to the birds in the area that they are leaving. The cygnets sensed the impending cold weather, heard and/or saw the other swans and left with them. Although a predator could have grabbed the young birds, if there was no evidence of a struggle or a bunch of feathers in the immediate area, it is not probable that they were attacked by a predator. The Regal Swan