Halo Project Predator Free project manager Jonah Kitto-Verhoef called it “a grim milestone”, but one worth acknowledging.
New Zealand’s introduced mustelids — ferrets, weasels and especially stoats — were public enemy No 1 for many native wildlife species.
And since January 1, 2018, 570 stoats, 325 weasels, and 136 ferrets had been trapped in the Halo project area.
Ferrets, which often preyed on rabbits, were less common in the area, but stoats and weasels, which often focused on smaller prey such as birds, insects and rodents were far more prevalent — and their presence was known to have devastating effects.
In 2015, a stoat incursion at Orokonui Ecosanctuary — which the project now encircles — nearly wiped out the resident saddleback (tīeke) population.
One den inside the predator-proof fence was reportedly responsible for the deaths of up to 60 of the endangered birds.
The project stoat network now extended across 12,500ha from Aramoana to Flagstaff around the West Harbour, Mt Cargill area, Mr Kitto-Verhoef said.
About one trap was set per 10ha, mostly on roadsides and public tracks.
The intelligent hunters with a high metabolism could cover a lot of ground and control efforts required large trapping networks.
Introduced in the 19th century with the aim of controlling rabbit populations, the mammals came from colder climates where they would kill and cache their prey.
In New Zealand where the adaptation was not required, they still cached their prey, except here they did not come back to feed on their kills.
“They kill a lot more than they actually consume.
“They are absolute killing machines, they are almost one of the best adapted killing machines out there.
“So, we try to everything as humanely as possible, but we really feel a strong responsibility for our patch, but also for biodiversity in New Zealand.”
The work was having an effect.
People in Ravensbourne were reporting seeing more morepork (ruru), robins were seen living outside the Orokonui predator fence and there were hopes the kākā population would expand.
This week he saw a kārearea (New Zealand falcon) at Heyward Point.
“It’s all these things that are the reason, we do it.
“And that is so exciting to see that we are now starting to see those biodiversity gains.”