Meet New Zealand’s ‘Moss Chicken’ - Could the Flightless Kākāpō Be Making a Flying Comeback?
- Bethany Akhtar
- Jul 10
- 5 min read
The beginning of this year marked a record-high breeding season for the Critically Endangered kākāpō, with over 100 eggs successfully hatched. But with chick survival still uncertain, does this milestone truly signal their recovery, or simply a fragile step forward?
A kākāpō being hand-fed on Anchor Island, New Zealand. Image Credit: Kimberley Collins on Flickr, licensed under CC by 2.0
Once widespread and thriving across New Zealand, the curious kākāpō is now at a low of just 235 individuals, fighting for their survival centuries after initial decline. Fortunately, their numbers are set to increase, thanks to the record-high success of the 2026 breeding season.
However, their comeback so far brings a genetic cost and worries about habitat space, making it easy to question whether this milestone is truly worth celebrating. So, what do we know about their decline so far, and what do the facts really suggest about their long-term recovery?
Firstly, let’s discuss the kākāpō
The kākāpō is the world’s only flightless parrot, endemic to a few, managed islands off the coast of New Zealand and mainland refuges. It is also the world’s heaviest parrot, where breeding males can weigh roughly the amount of a small, domestic cat or a large chicken. This, alongside their mottled, green plumage, has given rise to their nickname ‘the moss chicken’ - a fitting name for such an endearing bird!
Kākāpō are well-known for their friendly and curious demeanour. Historically, some were even kept as beloved pets (although they are strictly protected today!). Like pets, they are known to have unique personalities, with some more shy and others more noisy than the rest.
As ground foragers and tree climbers (of which they are excellent!), kākāpō play an important ecological role in seed dispersal on the forest floor, due to their diet of fruits and seeds from native plants like rimu trees. During breeding seasons, rimu trees become critical sources of food for the kākāpō, since the species only breed when these trees produce a heavy fruit crop, known as a “mast year”. This event usually occurs every two to five years, making kākāpō breeding a somewhat unpredictable but exciting event.
Sadly, this comprises one of the many factors which have led to their decline, and they have ultimately become ‘Critically Endangered’ on the IUCN Red List.
A New Zealand rimu tree (Dacrydium cupressinum). Image Credit: KimEdoll on Flickr, licensed under CC by NC-ND 2.0
Decline of the kākāpō
During their early evolution, kākāpō lived in isolation from mammalian predators and experienced very little competition from herbivores. This meant that they evolved with very few defence mechanisms other than their mossy, green plumage to camouflage themselves from birds. At the time, this was simply the only defence necessary.
Consequently, the arrival of Polynesians in the thirteenth century came as a shock to the species when they brought mammalian predators like Polynesian rats (Rattus exulans) and domestic dogs (Canis domesticus), which were able to spot the kakapo much more easily from the ground. Due to the kākāpō ground nesting process, where females often leave the nest to forage without the male to guard, their eggs soon became a favoured food source for invasive predators.
European arrival in 1769 then caused their population to decline further through the introduction of predators like stoats (Mustela erminea) and ship rats (Rattus rattus), as well as via human hunting for food and scientific collections. These settlers also accelerated forest clearance for agriculture, leading to significant habitat loss.
After the kākāpō population plummeted to 51 individuals in 1995, their genetic diversity reached a severe low and was worsened due to inbreeding within the small, leftover population. Ultimately, this limited the species’ ability to adapt to environmental changes.
Kākāpō conservation
As a result of their severe genetic and geographical decline, the Kākāpō Recovery Programme was created by New Zealand’s Department of Conservation to ensure kākāpō survival. Amazingly, the programme manages and monitors the entire population on the predator-free islands of Pukenui and Whenua Hou.
In February of this year, the programme celebrated its largest breeding season yet, welcoming the birth of 106 kākāpō chicks to the islands. But whilst this season brings fresh hope for the kākāpō, the species’ limited genetic diversity and few natural defences present significant obstacles to its full recovery.
5 day old kākāpō chicks (cropped image). Image Credit: Jake Osbourne on Flickr, licensed under CC BY-NC-SA 2.0.
Kākāpō recovery challenges
One of the biggest threats to the kākāpō, as a consequence of their low genetic diversity, is their susceptibility to diseases like Aspergillosis. Alongside natural chick mortality, an outbreak of disease within the growing, juvenile population could devastate much of the population, leaving them waiting 2-4 years for another breeding season to arrive. For example, during the 2019 nesting season, a single strain of aspergillosis killed 9 individuals and left 21 others affected.
However, the Kākāpō Recovery Programme enforces regular health and biosecurity checks, involving rapid medical responses when needed and strict quarantine measures. Therefore, the kākāpō is likely to be well-shielded from a catastrophic event, particularly during a significant period of chick-rearing.
On the other hand, preventing disease alone doesn’t fix the root cause of the problem. As such, the Kākāpō Recovery Programme is currently using gene sequencing to identify rare genes in the existing males. Once males with a more diverse gene pool are identified, artificial insemination of female kākāpō is carried out to improve the genetic diversity of offspring.
While these interventions are heavily resource-intensive and can be stressful for the individuals involved, it is clear that they are some of the most effective tools for improving disease resilience in birds. Plus, along with increasing disease resilience, these techniques will also reduce kākāpō infertility, which has affected 40% of their eggs since 1985 - another big win for their conservation!
Ecologically-speaking, another key problem being identified is the issue of sufficient, predator-free island space to support the expanding population. Luckily, New Zealand is already working towards becoming predator-free by 2050. While this sounds ideal for kākāpō safety, this poses significant ethical issues surrounding the killing of large numbers of mammalian predators.
Arguably, a balance could be struck to resolve the issue. Keeping kākāpō within large, robust sanctuaries could allow expansion onto predator-populated islands like the Sanctuary Mountain Maungatautari on New Zealand’s main, North Island. Either way, however, the odds already appear to be in the bird’s favour, with New Zealand already managing their invasive predator problem.
Therefore, it is likely that current conservation efforts and the recent breeding season is a sign of a slow, but sure recovery for the kākāpō. And it doesn’t stop there - you too can make a real difference by donating to the programme or ‘adopting’ a kākāpō via their website, where your contribution goes towards an individual’s care, feeding and veterinary costs. Equally, raising awareness about their conservation can help to foster a culture of stewardship and encourage others to donate for those who cannot.
Comments