How do I get the buoy?

Hint 1 of 13:

You need to make it fall down somehow.

Hint 2 of 13:

You can't reach it, no matter what you do.

Hint 3 of 13:

What if something else reached it for you?

Hint 4 of 13:

Something like a seagull, for instance.

Hint 5 of 13:

You need to attract a seagull.