We would certainly not qualify this as normal or abnormal behavior. You have 5 swans, which means that there is an odd male or female left out of a mating pair. The goose may have grown up in the area with the swans when they were young, fed among them as people threw food and they all became pals.

The goose and the swans have accepted each other and do not mind having each around. The lone goose and the lone swan may have become friends and may stay around each other until they eventually find a mate.

In some cases, swans will chase geese from the area due to their territorialism, but in your case, these are probably juvenile swans and much more tolerant at a young age. However, once breeding season begins, territorialism may become prevalent and the various swan pairs as well as the goose are chased from the area by the more dominant pair. The Regal Swan