A high tech predator control entity says it has eradicated all pests from a remote valley in South Westland and - what's more - is keeping them out.
Zero Invasive Predators - or ZIP - did the trial in a 12,000 hectare block within the Perth River valley near Whataroa last year.
After carrying out a 1080 predator removal operation in 2019, ZIP established a network of 700 traps for rats and possums, all connected by radio and satellite to rangers' phones and laptops, along with 142 cameras to detect predators.
ZIP CEO Al Bramley tells Kathryn Ryan the technology is bringing New Zealand closer to achieving predator-free status.
ZIP was established five years ago as a partnership between the philanthropic Next Foundation and the Department of Conservation.
Technology is effective maintaining an area after a 1080 drop, he says.
“People often get a bit confused here because they think on the mainland we can achieve predator freedom, we kind of can, but in actual fact they're always nibbling away at the boundaries.
“For us the important thing is detecting them quickly and not allowing large populations to establish. So, we're continually snuffing them out at the edges, and maintaining predator freedom at the core.”
In the Perth Valley they worked with the area’s topography to help get on top of stoats, rats and possums.
“There's Southern Alps, which means the back door’s effectively closed and there are big river systems and those big river systems are proving really effective at preventing predator reinvasion.
“They're not fool-proof, we do get some leakage, but it's very low because the rainfall so high, which means if we pick those rivers as boundaries, reinforce them, we can maintain control between the rivers.”
And a tasty egg-based treat along with some smart tech is proving highly effective he says.
“When we started this game [it was]peanut butter for our rats and rodents, and we tended to use meat-based lures for stoats.
“But we're largely using just one lure and it's an egg-based mayonnaise, and that seems to appeal to all pests.
“And the beautiful thing about mayonnaise is you can squirt it out of a syringe, which means you can attach it to an automatic lure dispenser which means that now the ranger doesn't need to turn up and continually refresh the lures.”
Bramley says the ZIP approach is increasingly surgical.
“We tend to lay detection networks that are now predominantly camera-based. And we don’t look for individual rat arrival, because if it's an old male - who cares, he's going to die out.
But if it's a pregnant female, and she has a litter, then what we do is we lay our predator detection networks, so that you detect that emerging population, before it gets out of control - so then you can snuff it out.”
They may use very targeted 1080 drops to nip a problem in the bud.
“Right now, we're planning to do our first spot treatment in the Perth Valley and it's about 4 percent of the area we're currently trying to maintain.
“We think of it as surgical now, that's where we want to get to, we want to be able to target the emerging family.”
He says ZIP is entirely focussed on one job.
“We don't get distracted by every other conservation problem of the day, we just focus on cracking rats, stoats and possums in remote places.”