The endangered kākāpō, New Zealand's heaviest parrots, are gearing up for a potential mating season like no other. With a bumper crop of berries from the native rimu trees, conservationists are optimistic about the prospects of a record-breaking number of chicks for these rare birds. But here's where it gets controversial: the success of this breeding season could also highlight the challenges of managing an expanding kākāpō population.
Kākāpō, the world's only nocturnal and flightless parrots, were once abundant across New Zealand. However, their population plummeted after the introduction of predators like cats and stoats, and by the 1900s, they were on the brink of extinction. A recovery program established in 1995 has since rebuilt the population to 236 birds, including 83 breeding-age females.
Kākāpō breed only every two to four years when the native rimu trees 'mast' and produce large numbers of berries. This slow repopulation is due to the birds' reliance on the abundant fruit for nutrition to raise chicks. This year, a 'mega-mast' is expected, resulting in a bountiful harvest of rimu berries, which could prompt the birds to produce more eggs.
Deidre Vercoe, the Department of Conservation’s operations manager for kākāpō recovery, said it was an exciting moment for her team. 'We’ve got a really big rimu crop developing on the trees and the birds haven’t bred for four years so we’re hoping that they will all get into the action this summer,' she said.
Kākāpō are thought to live between 60-80 years, can weigh up to 4kgs, and are famously entertaining. Their mating rituals are 'crazy', Vercoe said. Male birds gather in a 'lek' to produce a distinctive booming sound, emitted from air sacs in their chests while sitting in a dug-out bowl in the ground. The deep boom, which can travel up to 5km, sounds similar to a softly plucked cello string.
After choosing a partner and mating, females typically lay one to four eggs. The females become solely responsible for their eggs and hatched chicks for roughly six months. It's a mystery how kākāpō know when rimu are likely to mast, or why they rely on that particular tree. But the fruit is nutritious and, when plentiful, provides enough food for the birds to raise two to three chicks.
Kākāpō are extremely good climbers and can easily scale the 20-30 metre high rimu to access berries, she said. 'They are doing that over and over all night long for months – it’s really hard work, and quite amazing.'
Previous breeding seasons have on average led to the production of one chick per breeding female, and each season brings new challenges. This year, a higher number of younger females are ready to breed but they may not be as successful as older birds. 'I never like to count our chickens before they hatch, but we’re really hopeful that the majority of the females breed and we will get some good numbers of chicks through.'
As the population steadily grows, so too does the issue of where to put the birds. 'We are actually running out of space for kākāpō and predator-free, good-quality habitat,' Vercoe said. 'It’s an exciting turning point for the program – how do we keep growing the population, but how do we take steps back and where do we put them?' she said. 'It’s a challenge for New Zealand to grapple with.'
