There is a suite of small mammals – and one marsupial – inhabiting Mauao and Moturiki.
The main mammal is the rabbit, a pest who contributes to soil erosion and petrel burrow excavation.
Rats are opportunists, who take advantage of any site which has plenty of food. Eggs, seedlings, and chicks are fair game to this generalist feeder.
Possums were eradicated on Mauao in the 1990s, but are just starting to make a comeback. They prefer the pine trees on the seaward side of Mauao, but can be found almost anywhere.
Stoats (related to the weasel), can sometimes reach all our sites, as can be told in the tragic invasion of Motuotau in the early 2000s, where they killed dozens of Diving Petrels in a short period of time. They are also implicated in major kill events on Mauao in the 1990s and 2000s. One year there was nearly a 50% kill rate of chicks inside their burrows attributed to a stoat (they are distinctive in their kill techniques, biting the brains of birds).
Dogs – Dogs are not permitted on Mauao or Moturiki however, sadly, people ignore this ban at times and regularly dogs are responsible for killing penguins and penguin chicks, especially on Moturiki where they are so easy for a dog to find and reach into the burrows.
Cats – sadly cats are probably the biggest killer of some of our native birds in the area. Every year cats kill a large number of Diving Petrels as they try to nest on Moturiki. Cats that are allowed to wander at night are the culprits and we encourage owners to lock their cats inside during the nights.