Our Changing World: The challenge of making our capital city predator free

Two gibbons who are face to face shot from the side. There is a dark black gibbon whose face we can’t see, and a paler light brown gibbon with a black patch on the top of it’s head. The brown gibbon has it’s hands on the shoulders of the black gibbon. — Gibbons at Wellington Zoo Photo: Wellington Zoo

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On a hillside in Mount Victoria, nestled amongst the branches of a fallen tree, is a bait station.

There’s also a camera to take a photo of any creatures that visit this spot, a dispenser to drop small amounts of mayonnaise and a chew card filled with peanut butter.

Zara, wearing a high-vis orange vest and gloves, works at a bait station set among tangled branches and undergrowth in a forested area. — Zara Koorey of Predator Free Wellington checks a bait station. Photo: RNZ / Charlie Dreaver

Predator Free Wellington field operator Zara Koorey is checking the area to make sure the equipment is in working order and also for any signs of rats.

Looking at the markings on the chew card she sees something else has been enjoying the peanut butter.

Instead of the “M” shaped grooves of a rat bite, they’re completely flat, indicating a kākā has been scraping out the peanut butter.

A close up shot of a chew card which has been nibbled at along the edges and bottom. — The project uses chew cards to identify pests in the area, and sometimes to learn that kākā are around! Photo: RNZ / Charlie Dreaver

It can be a little frustrating, but it’s a sign of Predator Free Wellington’s success with its work to rid the capital of every rat, possum, stoat and weasel.

“We have so many kākā now because of the eradication project that the kākā are just eating all of our chew cards, which is great. So we love them. We’re not mad at them for it,” she said.

After Zara is done at each station, she uploads the information she has collected to an app, which is collated with data from Trap NZ and is loaded onto a map.

A map of the Hataitai area of Wellington with different coloured markers scattered on it - some red camera-like squares, some blue circles and green triangles. Each represent part of the PFW effort. They are clustered in the green space in the centre. — To coordinate the effort Predator Free Wellington makes use of apps and maps. Here a red camera means a rat sighting, and a green triangle indicates a rat-nibbled chew card. Photo: Predator Free Wellington

Each symbol on the map means something different. For example, a red camera means a rat seen on camera, and a green triangle indicates a rat-nibbled chew card.

This area is part of Phase Two, which covers about 1300 hectares from west of Rongotai, down to Ōwhiro Bay and up to the CBD, and is home to about 60,000 people.

So far more than 7500 households have signed up to have traps or bait stations in their backyard.

And project director James Wilcocks says they’ve learnt a lot from Phase One - eradicating the rats on the Miramar Peninsula.

A portrait shot of James Wilcocks at the top of Mount Victoria with a view of some of Wellington city behind him. James is smiling, with his hands in his jean pockets, and is wearing a brown zip jumper. — James Wilcocks, Project Director of Predator Free Wellington Photo: RNZ / Charlie Dreaver

” Miramar was all about kind of developing the model to get this work done. It’s never been done anywhere in the world before as far as we’re aware.

“So that was around testing, getting our methods right, and now it’s around really making those as efficient as we can,” he said.

But this new phase comes with challenging new locations, for example; Wellington Zoo, Government House, Massey University and Wellington Regional Hospital.

Te Nukuao Wellington Zoo director of safety, assets & sustainability Chris Jerram said that the eradication of the zoo’s rat population has been an “ongoing process” for many years.

And added that Predator Free Wellington has been working on the site since October.

During Our Changing World’s visit to the zoo’s Asia Precinct, Chris stops by the tiger exhibit where there’s lots of vegetation, which is not just great for tigers, but for rats too.

He said that the enclosure had been a hot-spot for the rodents.

Chris Jerram is Director of Safety Assets and Sustainability at Wellington Zoo Photo: RNZ / Charlie Dreaver

“So it was kind of like a multi-pronged approach to try and reduce the numbers down, which, Predator Free have shown through the data collection, that’s been quite effective.

“[It was] a combination of trapping and actually a bit of managing the habitat vegetation helped, clearing some of the edges as well.”

Chris said making some changes to feeding also helped keep the rats at bay.

Another difficult area is Monkey Island, because regular bait stations can’t be used.

“So that was one of the more tricky habitats to try and address because spider monkey hands are very long and they’re super curious,” Chris said.

Since Predator Free Wellington has been working with the zoo, the animals have also had detection dogs on site.

It was a learning experience for everyone and rat detection dog handler Sally Bain said the dogs weren’t a fan of the sun bear.

” They could smell it. And you could see them like, okay, I know I’m supposed to be here to look for rats, but I’m really scared right now!”

Sally is wearing a high-visibility orange vest, green jacket and baseball cap. She’s bent over in dense green vegetation with her hand down in front of Rapu, a small brown dog, also in a matching orange vest. — Sally Bain and rat detection dog Rapu at work Photo: RNZ / Charlie Dreaver

They were, however, much more at ease while looking for rats at Charles Plimmer park, and it’s there where 6-year-old terrier Rapu quickly found a dead rat near a bait station.

Kimi the fox-terrier has been trained to focus on live rats and just minutes later, both she and Rapu find not one, but two live rats in an area thick with ivy.

“Cape Ivy is our worst weed, English Ivy[..] the South American Pampus is another one that rats absolutely love,” she said.

These are just a few examples of some of the work that’s happening as part of the world-leading project and Predator Free Wellington is already seeing the fruits of their labour on the Miramar peninsula.

In its 2025 annual report, the group said the number of kōtare observed had increased by 550 percent, pīwakawaka by 400 percent and tūi by 210 percent.

James Wilcocks said there will be a new generation who will grow up in a city that may never see a rat, stoat or weasel.

“But they will see kākāriki and kākā and kererū because they’re part of their everyday lives now, and that’s gotta be a future that’s worth fighting for, right?”