I really felt for the little duck. It's not the best shot but you can see the duck desperately trying to get between the big nasty swan and her ducklings.
In the end, I had to shout at them and they settled down and went their own ways.
Pleased you were able to sort them out. Swans can be very nasty I once saw one trying to drown another swan by standing on it to keep it under the water.