A surprising discovery at Wellington’s Zealandia eco-sanctuary has raised fresh concerns about the protection of native wildlife. In just four days, the bodies of four weasels were found inside the normally secure sanctuary, prompting a swift and thorough response from conservation staff.

The first dead weasel was spotted last Saturday afternoon, after a member of the public noticed it in a DOC200 trap placed just inside the predator-proof fence. The trap had been checked and reset by rangers, yet by the very next day, a second weasel was caught in the same trap. Then, on Monday, another was found in a different trap. A fourth followed on Tuesday. All appeared fresh, suggesting they had only recently entered the sanctuary.

These traps had been set after a tree fell onto the fence during a storm in May. The damage may have created a temporary breach, allowing the weasels to slip through. As small mustelids, weasels can squeeze through holes no larger than a thumb, making them difficult to detect. Although there is no confirmed damage to the sanctuary’s wildlife, the discovery has sparked concern. Weasels pose a serious threat to New Zealand’s native birds, many of which are flightless and highly vulnerable. However, no evidence has been found to suggest these weasels harmed any animals before being caught.

Jo Ledington, the general manager for conservation and restoration, explained that the team acted quickly once the weasels were discovered. According to her, all the traps had been recently checked and rebaited, and the animals did not show up on any detection devices. Therefore, it is believed the weasels entered the valley only recently.

Despite this rare event, Zealandia’s biosecurity system remains strong. It includes motion-sensor cameras, tracking tunnels, detection dogs, and an extensive trapping network. These layers of protection help catch invaders quickly and keep damage to a minimum. The last weasel found inside Zealandia was in August 2024. Before that, another was caught in October 2023. Incidents like these are rare, with the last similar case going back to 2019.

In response to this latest breach, rangers have checked the entire fence again. More trail cameras are being installed, and a specially trained mustelid detection dog has been booked to search the area. Meanwhile, traps are being regularly monitored and baited to keep them effective. However, staff warn that confirming the sanctuary is free of weasels could take months. They also note that this work is costly. With the original predator fence now almost 25 years old, Zealandia is currently raising funds for a full refurbishment.

For now, the sanctuary remains on high alert. The team continues its efforts with determination, ensuring every step is taken to protect the native species inside. Supporters are being encouraged to help by joining as members or donating to the fence fund, ensuring Zealandia remains a safe haven for New Zealand’s rarest wildlife.