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How Decades Of Effort Brought Kōkako Song Back To The Forests
There were just 458 known pairs of kōkako 25 years ago, now their numbers have increased five-fold.
Manaaki Whenua - Landcare Research senior scientist John Innes had been part of the drive to turn those numbers around.
He devoted the last 44 years to protecting native birds and retires this week.
The call of kōkako still delighted him, he told Summer Weekends.
"I say, well, it doesn't matter really if you don't see one, but if you've never heard one, you will die poor."
As far back as the 1940s people were aware kōkako were slipping away, he said. But little was known about the bird.
"The modern era of research picked up, then people studied the bird and found that it spends its entire existence inside little territories where it has to find all of its food, and its nesting success was terrible."
Subsequent research showed 85 percent of nesting attempts failed, he said.
Ship rats, possums, stoats and harriers were the culprits.
What followed was 20 years of predator control, he said.
"And we were very gratified to see quite strong responses to that."
There are now 26 places around the North Island with kōkako populations.
There are 11 relic ones, but 12 of them are new and have been established by translocation. Three are on offshore islands - Little Barrier, Tiritiri Matangi and Kapati, Innes said.
Before the restoration efforts kicked in - because predation took place at night - the science was literally in the dark.
"The birds were disappearing in front of their faces because the bad stuff was happening at night, and it looked as if the birds were co-existing with their agents of decline."
Predation of eggs and chicks wasn't the only threat, he said.
"They need plenty of food to breed. They have big breeding years if there's a lot of food and not such good ones if there's not.
"They need excellent food availability. And if you want to maximise prospects for this bird and many others, then those two things have to happen together, lots of kai and safe passage through nesting."
In the early days, primitive time-lapse video revealed what was going on, he said.
"We initially built our own systems. The very first one I saw was in Hawaii, actually an American project, but we came back and built one at Forest Research Institute at Rotorua. We had to carry around big 12-volt batteries and it was all done with video.
"When we look back at this, the quality of the outputs is not so good, but the very first night we used it, it famously filmed a possum turning up at a nest. And it was extraordinary sort of unscripted television to watch and so that was the re-discovery, as it turned out, of possums as predators of bird eggs and chicks in New Zealand."
Kōkako needed good healthy forests and predator control had helped too, he said.
"Forests need to be in good condition. Ship rats and possums, they're not just predators they're also tree climbing. Possums eat leaves and fruit, and ship rats eat fruit and insects, and kōkako feed their chicks insects.
"So, you have to improve the condition of the forest, and a combination of predator control of browsing mammals will do it."
With good food supply, kōkako would make up to three breeding attempts a year, Innes said.
Drops of 1080 in inaccessible areas had proven a vital tool in reviving kōkako populations, he said, which was now much more targeted.
"We did a lot of work, five years' worth really, to verify that kōkako survived aerial 1080 operations, fine. And in fact, it helps all aspects of their little lives."
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