No, these aren't ugly ducklings, they're beautiful swans. Or cygnets, if you prefer.
Their mother was nearby, and later she took them for a swim down the River Coln. Here she is, showing her babies how to search underwater for food:
Lots of waterfowl live in the River Coln near Bibury, in the marshy area known as Rack Isle. It's named for the drying racks where the weavers at Arlington Mill hung their cloth to dry. As we watched one duck make her way through the passageways formed by the grass growing through the shallow river, it occured to me that living in such a place must be much more interesting than some boring pond.