New data reveals that hundreds of pests are using Wellington's Transmission Gully road to enter the region, threatening to undermine the capital's huge and expensive efforts to eradicate predators and protect native birds.
The 27km motorway opened two years ago - since then kiwi have been released into the hills surrounding the city, and they could now be at risk.
Data obtained by Greater Wellington Regional Council from Waka Kotahi show that 226 pests have been trapped or found dead on the road between November 2022 and January 2024, including stoats, rats, weasels and ferrets.
Council chair Daran Ponter said that's because of the vegetation and beautification along the roadsides.
"What that is doing is attracting pests into the road corridor, and they are using it just like we are using it - to travel up and down," said Ponter.
That's putting Wellington's goal of becoming the first predator-free capital in the world, at risk. Over the past few years conservation groups have eradicated all rats, stoats and weasels from the urban area of Miramar Peninsula, and reintroduced wild kiwi to the hills behind the city.
"Despite those efforts we have these corridors that are going to invite and continue to invite these pests in," said Ponter.
James Willcocks from Predator Free Wellington shares his concern.
"Stoats have single-handedly made a number of our native species extinct, and ferrets are capable of taking out an adult kiwi," he said.
"We've just got them back in our city for first time in well over 100 years, so the stakes are pretty high."
Currently $16,400 a year is spent on pest control along Transmission Gully, but the regional council and Predator Free Wellington want to see more funding and better collaboration between agencies.
"One of the things that NZTA is going to have to consider is doubling down on the budget they already have," said Ponter.
"Considering we don't have ferrets in Wellington City, it's going to be a lot cheaper to keep them out than it is to deal with any issue once they arrive in the city. Prevention is far far better, far far cheaper than the ambulance at the bottom of the cliff," said Willcocks.
Waka Kotahi told Newshub it will meet with the council to discuss the issue, but at this stage it's too soon to speculate on what the solution might be.
"As part of the development of SH1 Transmission Gully, work was undertaken with a range of specialists to understand and manage the potential impacts of the motorway on its surroundings. Pest control efforts were carried out throughout its construction, and this has continued since this section of SH1 opened to the public just over two years ago," said a NZTA spokesperson.
The regional council is urging NZTA to take its learnings from Transmission Gully and apply them to the Kāpiti Expressway immediately.
"Businesses and landowners have more than enough trouble with rabbits and can do without the additional fear of a Kāpiti Mustelid Express Pest-way on their doorsteps," said Penny Gaylor, chair of Greater Wellington's Environment Committee.
