The Plunder Island Naturalist Society was a group concerned with the safety, preservation and study of the wildlife of Plunder Island, in particular the chickens.
Some members have been killed while putting on their plaques. One possible member of the Society is Mrs. Brinestoop. While Guybrush was eaten by a giant snake, he discovers a reservation slip for Blondebeard's Chicken with the name on it. He also found the remains of a naturalist member, possibly belonging to Mrs. Brinestoop. Another one was killed by drowing in quicksand.
Close to the Plunder Island Fort was a plaque placed there by the society reading:
"Plunder Island Feral Chicken. One of Plunder Island's most common fauna, and the animal for which our capital of Puerto Pollo is named."