Seagull

The Duck in Hydro-Hopper.

Ducks are creatures found around Club Penguin. Currently, they can only be found in the game Hydro-Hopper.

Trivia

Most Penguins do not know that ducks exist in Club Penguin.
Gary invented a Rubber Duck as a spy gadget.
The Ducks in Hydro Hopper will dip its head into the water and swim towards you.
Ducks are the only avian creature in Club Penguin'
There are two inflatable duck clothing items, the Green Duck and the Yellow Duck.
Ducks are one of the rarest creatures in Club Penguin.
In the Club Penguin book The Ultimate Official Guide to Club Penguin, they say the ducks are actually seagulls.