New Zealand authorities are prepared to spend $300,000 on a campaign to eliminate a male stoat that has appeared on an island home to many rare species.
For the past 25 years, a remote area in southwestern New Zealand has provided a predator-free sanctuary for threatened species, including the world’s only flightless parrot and a lizard that cannot be found anywhere else. Chalky Island, a rugged, lush land covering 5.2 km in the Fiordland region, is home to the Te Kākahu skink, kiwi birds, and the critically endangered kākāpō parrot, of which there are fewer than 250 individuals remaining in the wild. Therefore, in August 2022, when conservation staff on the island detected a male stoat, a mammal native to mainland Eurasia and North America that preys on birds and various other prey, they were compelled to take action to save the fragile ecosystem on the island, according to CNN.
The stoat was detected by a camera on Chalky Island. (Photo: New Zealand Department of Conservation).
The Department of Conservation (DOC) of New Zealand has initiated a large-scale operation involving trapping experts, detection dogs, camera traps, helicopters, and boats over an 8-month period to trap and kill this stoat. “This is a significant victory, but we cannot let our guard down at this point. The island is one of the top biodiversity priorities in Fiordland. We need to do everything we can to protect the vulnerable species that live there,” said Rebecca Teele, a DOC specialist.
In March, the New Zealand Parliamentary Environment Committee revealed that the cost of the mission to catch the stoat would be $300,000. This substantial amount has sparked considerable debate on social media, but authorities believe it is worth the investment. “If we do not act, we will pay a much greater price, with the potential to devastate the kākāpō population. We might have to evacuate kākāpō from the island by air at enormous costs, and there is nowhere to relocate them. The opportunity cost of not capturing this stoat could reach millions of dollars,” said Aaron Fleming, DOC’s operations director.
Alongside ferrets, stoats were introduced to New Zealand in the late 19th century to control rabbit populations that were decimating sheep pastures, but they have also eradicated unique bird populations here, contributing to the extinction of several subspecies, according to DOC. These new predators kill approximately 25 million native birds in New Zealand each year, with around 4,000 species threatened or at risk of extinction.
In an effort to protect them, New Zealand has invested over $300 million since 2016 to pursue the goal of becoming a predator-free country by 2050. Under the plan, the government intends to eradicate rats, possums, ferrets, and stoats.
According to Carolyn M. King, an honorary professor at the University of Waikato, stoats are small, energetic predators that efficiently kill native birds and lizards. They are small enough to enter rabbit and rat burrows, as well as the nests of many bird species, and are adept at squeezing into tight spaces. They are also excellent swimmers. Studies on a small group of stoats have shown that nearly half can swim continuously for over an hour, increasing the risk of them invading islands located 3 to 5 km from the mainland, including Chalky Island.
Chalky Island and the nearby Passage Islands have been free of predators since 1999 following the first eradication campaign against stoats. For Fleming, the recent appearance of the stoat further underscores the importance of the 2050 plan.
