Dead weasel found in Zealandia’s biosecurity trapping network
Yesterday our solid sanctuary biosecurity systems put in place by our conservation team were put to the test, with a weasel discovered dead in a DOC200 trap at the southern end of the sanctuary. The good news is our safe-guarding systems are working.
This week the world celebrated World Ranger Day, and this discovery is a reminder of the critical role our rangers play every day in protecting the vulnerable species that call Te Māra a Tane home. These rare native species haven’t evolved with introduced predators like weasels, so we are pleased we have trapped this animal.
Incursions don’t happen often, but when they do our rangers put their other work on hold and focus on carrying out a well-honed response. Our rangers and their volunteer ranger assistants are out today checking the fence on this rainy, windy Wellington day.
In conservation we never leave things to chance. To figure out if there are any more intruders, our rangers are pre-baiting even more traps and setting out trail cameras. This enables the team to respond to any further threats, so that the taonga within our care remains safe.
On top of carrying out this response, our rangers also carry out pest audits twice a year which are designed to detect any mammalian predators. We also haven’t had any sign of predation, nor do we have any sign that other introduced mammals remain in the sanctuary. In time, a mustelid detection dog will be brought in to help give the ‘all clear’.
Fortunately, introduced predators infiltrating our fence isn’t a common occurrence. The Zealandia fence is very effective at keeping species like weasels out, but very occasionally they get in and we need to respond.
Responding to events like this is expensive, and we are thankful to all the staff and volunteers who make it happen. We need your help to keep doing this work. Please donate today. Regular contributions in particular help support this ongoing, mission-critical work, and ensure we are always ready to respond.
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We will be updating this page if we find out more, so please check back for updates.
FAQs
What has happened?
A weasel was found dead in a trap set within the Zealandia sanctuary. This is one of our DOC200 traps that is always set as part of our standard biosecurity measures.
Why is that bad?
Weasels were introduced to New Zealand. Our native species aren’t well adapted to live with these very impressive predators. The Zealandia fence is very effective at keeping species like weasels out, but very occasionally they get in and we need to respond.
Has this happened before?
Yes, we had a weasel found dead in a trap in October 2023, and there was also an incursion in 2019. While this isn’t a common occurrence, we have some traps that are always set as part of our standard biosecurity measures to help deal with any incursions. In both 2023 and 2024, the weasel was found in one of these traps.
How did the weasel get in? Where was the likely point of entry?
We aren’t sure yet. Weasels can get through a tiny hole the diameter of your thumb. Our team are out checking the fence right now to make sure there are no further risks.
Are there likely to be more weasels?
We think this is unlikely, but we want to make sure. Our next steps include re-checking the fence to make sure it’s secure, pre-baiting more traps (where we put bait in traps without setting them to get animals to start trusting the trap), reviewing the footage from special trail cameras used to spot any animals moving around the sanctuary. We have a mustelid dog booked to come through the sanctuary later in the year to do a search as part of our standard biosecurity measures. We may choose to bring a dog in earlier depending on what we find over the coming weeks. Mustelid dogs are another useful tool to hopefully confirm we are weasel-free.
Are the birds in danger?
Weasels are good predators, but they aren’t nearly as voracious as stoats and ferrets. We have seen no sign of predation of birds by weasels in the sanctuary and no mammals were detected in our last Pest Audit in April.
What is happening now?
First, we re-check the fence to make sure it is secure. Second, we pre-bait more traps. This just means we put bait in without setting them. This step is important as it ensures the introduced animals start to trust the trap. Within a week we will set these traps to catch any remaining animals. Another step we take is putting out special trail cameras to spot any animals moving around the sanctuary. We have a mustelid dog booked to come through the sanctuary later in the year to do a search as part of our standard biosecurity measures. We may choose to bring a dog in earlier depending on what we find over the coming weeks. Mustelid dogs are another useful tool to hopefully confirm we are weasel-free.
How did the incursion response go last year? Did you find any more weasels?
No further weasels were detected in the sanctuary last year after a weasel was captured in a trap in October. Using our standard protocols, the Conservation and Infrastructure teams and volunteers monitored the valley until mid December when a mustelid conservation dog was brought in for final confirmation that no mustelids were present in the valley.
How can people help?
Responding to events like this is expensive and can take months to be 100% sure the sanctuary is safe. Right now, we could do with your support through becoming a member or making a donation on our website.
Photo credit: DOC200 trap - photo from Predator Free NZ website, credit John Bissell.
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