Mute Swans are not indigenous to North America but have been steadily establishing in many parts. They are now well established in the coastal waters around Vancouver Island.
They are the most aggressive of swans and it is feared they will upset the balance of the native Trumpeter Swan habitat.
This swan was actually driving off a Trumpeter Swan and this is typical of the aggressive posture indicative of the Mute Swan.

See I can still take bird shots:-)