A Swan will posture, and charge, with their wings pulled back and arched. They are territorial and aggressive.
This bird is charging to protect his mating territory. In addition he is charging right at the photographer to protect his territory. One more in addition…the photographer is oblivious to this behavior.

Adults of this large swan typically range from 140 to 160 cm (55 to 63 in) long, although can range in extreme cases from 125 to 170 cm (49 to 67 in), with a 200 to 240 cm (79 to 94 in) wingspan.

At the last moment he turned aside, swam close, and gave me a ‘dirty look’.

I have seen Swans attack kayaks and win. When angry they can hurt.
Click, or double tap, any image to view the Swan making his point known.