The only time I see a big body of water is on vacation, so I don’t get to see seagulls that often but I have noticed that if you want to see a lot of them at one time, you need to go to a harbor where fishing boats are as they wait for scraps. They ride the waves when floating on the water, perch on objects on land and even pick up a piece of 2×4 board to drop on my head as they fly over.
Feathers are very important to a bird so they spend lots of time caring for their feathers. Seagulls use their beaks and feet to clean and arrange their feathers as the preen. They have an uropygial gland (or preen gland) which produces an oil that waterproofs as well as conditions and improves flexibility of the feathers.
Seagull Preening
The video shows the seagull preening itself as the waves crash on the rock below.