Auckland's population of threatened kokako is soaring to new heights, with a massive drop in predator numbers.
Officials say most of that's down to the dropping of 1080 pellets, allowing the bird species, which is only found in New Zealand, to flourish.
Deep within Auckland's Hunua Ranges, the plan to help save the kokako is playing out. It's intensive and meticulously planned.
"For about 20 years we've been actively managing kokako in this area, since about 1994," says Auckland Council biodiversity manager Rachel Kelleher.
Back then, there were fewer than half a dozen breeding pairs in the area. Now, the number is closer to 60.
Ground trapping had helped, but officials say in the past two years, it wasn't enough, as predators were running rampant. So Auckland Council needed a different way to deal with the problem.
"We considered different bait types," says Ms Kelleher. "We looked at trapping, but at the end of the day the most effective methodology and one that would allow us to treat a substantially greater area, was the aerial application of 1080 baits."
The method is controversial, but one that so far appears to be working as planned.
Across nearly 22,000 hectares, the presence of rats in monitored tunnels has dropped from 91 percent to just 1 percent.
And inside the much smaller kokako management area, the number of rats and mice detected since the initial 1080 drop in August is zero.
"Certainly we can only usually achieve that for very short periods, so usually we all have some presence," says Auckland Council ecologist Su Sinclair. "So to have zero for quite a few months in a row is really great. It's quite new for us."
And, for the first time, a breeding pair has been spotted outside the intensively controlled kokako management area.
"Like a dream come true – when I first started here, it was the goal," says Department of Conservation ranger Hazel Speed. "But it's a lot of hard work and it takes a long time."
As the population increases, so does the need for vigilance. To monitor the newborn chicks teams need to set up ropes so they can scale trees to reach the nest.
Now they want to put bands on the chicks for research purposes, but there's limited time to do it. They need to be attached when the birds aren't too small, or too big.
With Mum and Dad watching on, the newborns are carefully lowered to the ground, where banding and measurement taking begins.
Dave Bryden's job is to spot and monitor Kokako. Last year he monitored six pairs, with disappointing results.
"In fact none of the nests even managed to get any chicks, because all of the eggs were eaten by predators within the first 18 days of incubation," says Mr Bryden.
The effects of 1080 poison won't last forever; predators will always come back.
But the hope is by boosting the number, the kokako's battle for survival will become much easier.
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