New Zealand just eradicated 200,000 mice from a single island in an extermination unlike anything we’ve seen before. Invasive species can wreak havoc on the environment, and as much as we hate to hear about the mass killing of any animals, sometimes it’s the only way to rescue a struggling ecosystem. In New Zealand, invasive predators like rats, mice, and possums have overrun islands and local bird species, invertebrates and plants have been destroyed. Entirely eradicating mice on Antipodes Island will give native species a chance to thrive, and it could provide a roadmap to help other countries deal with their own invasions.
New Zealand is home to more species of seabird than anywhere else on Earth, with 21 species using the Antipodes as a breeding ground. Hoards of mice overwhelmed the chicks and eggs on the island, and they threatened to kill entire species of invertebrates, which has a huge impact on the ecosystem. Mice have already wiped out two types of insects on the island.
Over the past 5 years, New Zealand used an aerial baiting program to spread rat poison every 15 to 30 feet on every part of the island. “This is achieved through precision GPS delivery from helicopters, which minimizes any toxin entering the marine environment, and has very few side effects on other animals because the poison is most strongly acting on land mammals, which aren’t normally found on islands,” said Dr. James Russell from the University of Auckland to Earther.
The island ecosystem is already recovering, with birds who competed with mice for insects making a comeback. The project could help Gough Island, where seabirds are being driven to extinction by mice, eradicate its own mouse problem. “Nearly half of our world’s most threatened species are found on islands, with invasive species as a primary threat,” Sally Esposito with Island Conservation told Earther.
Images via Department of Conservation New Zealand