A second kakapo has died this month, reducing the population of the endangered bird to 151.
The native parrot Jimmy was found dead on Codfish Island (Whenua Hou), kakapo recovery scientist Dr Andrew Digby said on Twitter.
Digby said it appeared the bird died from complications after an X-ray to investigate a wing injury two weeks ago.
The Kakapo Recovery team discovered Jimmy was dead last Tuesday and waited for the necropsy results to announce his death.
He was flown to Invercargill to get a full veterinary check-up with a suspected broken wing in November.
After being cleared of any broken bones Jimmy was declared well enough to return home.
When the team checked up on him two weeks later it was discovered he had died due to a complication with his wind-pipe following his anaesthetic procedure.
"It's always a very tough call to remove animals from the wild.
"We do it as little as possible for kakapo, but have to balance against risk of doing nothing.
"Many kakapo lives have been saved by veterinary intervention," Digby told his followers.
"We're all a bit gutted.
"We know all these birds individually and they all have their own personalities.
"There's not many of them left," Digby told the Herald.
Jimmy was first discovered by the team in 1983 as an adult and was one of the oldest birds known to the team.
"When it's one of the founders like Jimmy it's a harder blow to take because we have a bit more invested in them," Digby said.
Two weeks ago, young kakapo male Blake died following heat stress, a casualty of record-breaking dry weather in the South Island.
At the time the West Coast had been unusually dry with Greymouth and Westport breaking historical records for consecutive days without rain.
"Depending on what happens on Hauturu this summer, the population will likely go down before it increases again.
"Conservation gains for endangered species are hard-fought.
"We'll learn from this," Digby said.
• Following Jimmy's death there are only 151 left alive.
• They are are the world's only flightless parrot.
• Despite not being able to fly they have strong legs that help them run and climb trees.
• They are nocturnal.
• They are one of the longest-lived birds - they can live up to 90.