I understand that the correct word for young swans is cygnets. Nonetheless, since young ducks are called ducklings and young geese are called goslings, I often think of young swans as swanlings.
Here are four Mute Swan swanlings with their parents. It is interesting that three of them are grey morphs. It was also interesting that they did not move away when a companion and I appeared from behind a screen of phragmites.