T HE KAKAPO , a cuddly bird that lives in New Zealand, is not designed for survival. Weighing up to 4kg, it is the world’s fattest and least flighty parrot. It mates only when the rimu tree is in fruit, which happens every few years. Like other weird and wonderful creatures of the antipodes, it evolved in the absence of land-based predators, so instead of soaring above the trees it waddles haplessly across the dry forest floor below. When it stumbles across something that might kill it, it has the lamentable habit of standing still.

Such oddities turned the kakapo into fast food for human settlers—and for the cats, rats and possums they brought with them. It seemed extinct by the 1970s, until scientists stumbled on two undiscovered populations in the country’s south. These survivors were eventually moved to small predator-free islands, where the Department of Conservation has spent decades trying to get them to breed.

Its patience may finally be rewarded. The rimu was in fruit this year, and more than 80 chicks hatched after a bumper crop, making this the best breeding season on record. Many have survived into adolescence, increasing the number of adult kakapos by a third, to 200 birds.

But another threat to the kakapo is a lack of genetic diversity, because of low numbers and inbreeding. This is one reason why fewer than half of kakapo eggs hatch. By sequencing the genome of every living bird, scientists can identify closely related individuals and prevent more inbreeding by putting them on different islands. Well-matched birds cannot be forced to mate, but artificial insemination is also proving effective. Every bird is fitted with a transmitter to track its slightest movement. If a female mates with an “unsuitable” male, the process can be “overridden” with another bird’s semen. Time is of the essence, so drones are being used to whizz kakapo sperm to the right place.

This helps the males whose advances are rejected by fussy females, so would not otherwise procreate. It also allows researchers to identify useful genetic traits. One male, Gulliver, was found to haveunique disease-resistant genes. Andrew Digby, the programme’s scientist, thinks it “could hold the survival of the species”.

A bias towards male chicks has been corrected with a blunter tool: dieting. Fat females seem to produce more male offspring, so each bird’s transmitter is used to unlock hoppers that dish out strictly calorie-controlled meals. Once laid, some eggs are sent away for incubation and replaced by smart fakes, which wiggle and cheep so that the mother is primed for her hatchling’s return. Sickly babies are reared for months by hand.