In 1995, the entire population of kakapo, a flightless, moss-green parrot native to New Zealand, numbered just 51 birds. The species was on the brink of extinction. In a final effort to save it, conservation authorities gathered the remaining survivors and moved them to remote, predator-free islands. The relocation was a desperate measure, and its long-term success was uncertain.
The kakapo is an unusual bird. It is the heaviest parrot in the world, with some males weighing nearly four kilograms. It cannot fly, navigating the forest at night on strong legs and climbing trees with its beak and claws. It has an exceptionally long lifespan, potentially reaching 90 years, and carries a faint, sweet scent. For millions of years, it lived without natural ground predators in New Zealand, so it developed no instinct to flee from danger. When frightened, it freezes in place, an instinct that was effective against aerial threats but proved fatal when new predators arrived.
The decline began around 700 years ago with the arrival of Polynesian settlers, who hunted the birds and introduced the Polynesian dog and Pacific rat. European settlement in the 1800s intensified the pressure through habitat clearance and the introduction of new predators, including cats, stoats, and additional rat species. The bird’s instinct to freeze made it an easy target. By the late 1800s, it was clear the kakapo was disappearing.
In 1894, Richard Henry led the government’s first attempt to save the species by moving several hundred birds to Resolution Island. It was one of the earliest organized wildlife rescues, but it failed. Stoats, which could swim, reached the island within about six years and destroyed the relocated population.
By the middle of the 20th century, the kakapo was presumed nearly extinct. Between 1949 and 1973, more than 60 expeditions found only six birds, all male, in Fiordland. Most died within months. A species cannot recover from males alone, and the kakapo seemed destined to fade away. In 1975, a male was found in the mountains above the sea and named Richard Henry, after the earlier conservationist. He was the last known survivor of the Fiordland population, distinguished by a different dialect and brighter green feathers. Still, he was male, and without females, the species had no future.
The turning point came in 1977 on Stewart Island, known as Rakiura, where searchers heard the deep booming calls of many males. Around 200 birds were living there, and in 1980, females were discovered. For the first time in a century, the kakapo had a potential future. But feral cats were already killing the birds quickly. Conservationists chose to move the survivors to safer islands, carrying them out one at a time between 1980 and 1997 to sanctuaries such as Codfish Island, Maud Island, and Little Barrier Island. The remaining Fiordland males, including Richard Henry, were relocated as well.
Relocating the birds did not solve all their problems. Even where safe from cats and stoats, the kakapo struggled to breed, and rats on some islands killed chicks in their nests. By 1995, only 51 birds remained, including just 20 breeding-age females. Decades of effort had failed to produce enough chicks to sustain the species.
New Zealand then overhauled its approach, launching one of the most intensive conservation programs ever attempted. Every kakapo was tracked by name, and the team made a commitment to prevent the species’ extinction. A long-standing mystery was central to the effort: the kakapo would not breed on demand. It breeds only once every two to four years, and for years, no one understood why.
The answer was tied to the rimu, a native conifer. In years when the rimu produced a heavy crop of fruit, a phenomenon called a mast, the kakapo bred. Extra food offered in non-masting years rarely worked. In 2015, researchers at Massey University identified the missing link: rimu fruit is unusually rich in calcium and vitamin D, nutrients essential for producing healthy eggs and chicks. Because the nocturnal kakapo gets little sunlight, it cannot produce vitamin D the way most animals do. It had evolved to obtain these nutrients from the rimu instead.
Understanding this biological connection allowed the program to align its efforts with the rimu’s natural cycle. Modern techniques were applied, including radio transmitters on every bird, incubators for eggs, and the use of sensor-equipped fake eggs to keep mothers nesting while their real eggs were cared for. Some birds received artificial insemination, and weak chicks were hand-reared before being returned to the wild.
The program began to show results in the late 2010s, with the population slowly increasing. Then, in 2019, a respiratory fungal disease called aspergillosis swept through the birds on Codfish Island. Twenty-one birds fell ill and nine died, including nesting females and chicks. The population dropped to 211. In response, more than 50 high-risk birds were flown to veterinary hospitals on the mainland, where they received full-body scans and treatment. The outbreak was contained, and by 2022, the population had reached 252 birds, the highest number in half a century.
The recovery program achieved its largest recorded breeding season in 2026, when the rimu produced an unusually heavy mast. Across the breeding islands, 80 nests held more than 250 eggs, and at least 95 chicks hatched. It was the biggest breeding season in the history of the recovery program. A species that had been reduced to 51 survivors produced one of its largest generations in living memory.
The program’s long-term goal is to reduce human intervention and allow the kakapo to live more independently. The hope is that, with enough birds and enough protected land, the species may eventually return to the wild without the need for backpacks, incubators, or round-the-clock care. Some conservationists even envision a day when kakapo return to the mainland, their booming calls once again heard in the New Zealand night.
