Kiwi numbers are growing for the first time ever in a remote part of Fiordland.
Its population at Fiordland's Shy Lake is growing about 2 percent year-on-year - reversing a previous decline.
The growth is the result of recent aerial predator control operations, the Department of Conservation (DoC) said.
Before the use of 1080, the department said predators were out of control and chicks had a "zero" chance of survival.
DoC project lead Chris Todd said it was a significant win.
"It means not only are chicks surviving long enough to replace the adults, enough are making it to adulthood to officially grow the population."
Todd said the population would be "on a downward slide to extinction" if action wasn't taken.
He said Fiordland kiwi live in harsh, rugged terrain.
"Even without the threat of predation, it can be an uphill battle surviving through to adulthood. We can't control the environment but we can do something about the stoats and give these chicks a better chance."
And it's hoped the population will grow further after another round of predator control planned for later this year.
"Despite the challenge ahead, we've made a great start," Todd said. "The purpose of the study was to find out how to protect these remote kiwi populations and we now know it's an effective method for protecting tokoeka kiwi."
