The major threats to marine birds are the predators which have been introduced by humans over the last decades and centuries – dogs and cats, rats, the Manu toke toke or chimango and the Argentine ant. These animals cause terrible consequences on the native wildlife of the Island. To check on our ideas of what occurred, we set up an experiment at the empty nests of the Ranu Raraku colony. We put chicken eggs in some nests that had been recently occupied and installed hidden cameras to see which predators might have been coming and what they were doing with the eggs. The most frequent visitors were the rats. They often tried to break the eggs, but only one was successful. The same happened with the Manu toke toke birds. Other predators were stray dogs and cats who have become feral. Their mortal effects were confirmed in June of this year when personnel of the Ma’u Henua Native Community and Conaf found some 10 dead birds which had been attacked by a carnivorous animal in their nests.