The endangered rowi kiwi returned to its South Island home today in the largest ever release of the species.
The Department of Conservation released 35 of the kiwi into the northern region of the Okarito Forest.
About 20 of those birds were introduced into territory that kiwi had fled from more than 20 years ago.
Rowi project manager Jim Livingstone said the expansion of their home territory was a massive milestone for the critically endangered birds.
"The department is increasing the species' numbers pretty consistently, meaning we're now in a position to help these birds claim back old habitats," Mr Livingstone said.
The rowi is the rarest kiwi species in the world with a population of only 385. Numbers of the bird have plummeted due to predators, such as the stoat, and the loss of their habitat.
"Things have been bleak for the rowi. Birds were gradually pushed further and further south until they were backed up against the Waiho River, which they were unable to cross. It's just good luck that they were left with a last section of forest to prevent the species from dying out completely," Mr Livingtone said.
The kiwi were removed as eggs and were hatched at Willowbank Wildlife Reserve in Christchurch before being raised on a predator free island in the Marlborough Sounds.
The rowi was discovered to be an entirely new species of kiwi in 1994.
NZPA