I hope you sell the pics to your local newspapers- they are great!
Swans need a lot of food in the winter.
Here on Ammersee where we used to have our boat there are also swans. The fisher in front of whose area our boat was moored used to feed about a ton of grain to the water fowl in winter. It happened every now and then that the babies were not big enough to leave in winter, then the family staid and ate and ate and ate.
We always funded some grain as well