Eradicating mice from the Antipodes Islands

In a world-leading conservation effort, mice have been successfully eradicated from the Antipodes Islands in New Zealand’s Sub-Antarctic.

Found  760 kilometres south-east of New Zealand, the Antipodes Islands are one of New Zealand’s five Sub-Antarctic Islands. Known for bad weather, fog, rain, high winds, hail and snow at any time of the year, they are internationally acknowledged as one of the planets unique, wild and near pristine ecosystems. Home to a raft of endangered and endemic species, they are a life-raft for numerous albatross, seals, petrels and penguins who use the islands to breed, feed and rest. 

Mice were the only mammalian pest species on the AntipodesThought to have been introduced in the middle of the 20th century from a ship wreck or from one of the many sealing trips to the islandThe mice eat the eggs and chicks of seabirds and have been implicated in the deaths of albatross chicks on other Sub-Antarctic Islands. They also eat huge numbers of insects and the seeds of plants that are critical to the health of the islands. If these inhabitants were to thrive, mice needed to be eradicated. 

Enter the New Zealand Department of Conservation, they sought funding from the New Zealand public, who gave generously, raising $250,000 towards the project. World Wildlife Fund-New Zealand (WWF) kindly gave $100,000. The Morgan Foundation matched the donations dollar for dollar and brought other key partners together to raise enough money to get the project underway. Island Conservation also joined the team providing more generous support. The rest of the final cost was funded by the Department of Conservation. 

The remoteness, non-target species and the lack of facilities on the island were just a few of the other problems for the project. Careful planning was required to work with and overcome these challenges. The estimated mouse population was over 200,000 or up to 150 mice per hectare. In June 2016 eradication began with the team staying on the island for 120 days. The winter months were chosen as the best time as that is when the mice numbers would be at their lowest, with little food resources and when they have ceased breeding. Most seabirds are also away during this time. 

The basic principle for successful eradication required bait to be available in the home range of every mouseGPS monitoring was used to guide flight lines for the helicopter pilots with flight paths recorded and analysed to ensure there were no gaps. 

To confirm the eradication had been successful, comprehensive monitoring was carried out to detect if any mice had survived. The Department of Conservation announced in March 2018, that the Antipodes Island were officially predator freeThe joint initiative successfully delivered one of the most complex island eradication projects ever undertaken. The special plants and wildlife can now thrive with mice no longer preying on the insects or competing with the land birds. 

Million Dollar Mouse was a huge collaborative effort – it couldn’t have happened without the partners, the New Zealand public and supporters from all over the world. Now focus has shifted to the next goal: achieving a pest free Sub-Antarctic with Maukahuka – pest free Auckland Islands. 

So, if you’re looking for a country were collaboration meets sustainability, we know a place.