Kakapo (Strigops habroptila)
The cute Kakapo (image from https://ebird.org/species/kakapo2)
Stocky, owl-like and a little bit dopey, the nocturnal Kakapo is the world’s heaviest parrot, and unlike its fellow feathered friends, it doesn’t fly, but rather spends its time running around on the forest floor. This isn’t the only thing that makes this New Zealand parrot unique; its appearance is distinctly un-parrot like, with a flat, owlish face lined by specially textured feathers, short stumpy legs, large blue feet and short wings and tail. There are also records of individuals living up to 100 years old, making the Kakapo possibly the longest-lived bird in the world. They are known to be very curious and will often interact with humans; the rangers who monitor these birds say they all have unique personalities and will often come right up to them to nosey at what they’re doing.
A uniquely un-parrot like parrot
Like so many of New Zealand’s species, the Kakapo has evolved to fit into a niche left behind by mammal species long gone from New Zealand; the only native, non-marine mammals left in New Zealand are just three species of bat. Although they can’t fly, Kakapos are excellent climbers, reaching the tops of the tallest trees, from which they can parachute down to the ground, using their short stubby wings to glide. Their flightless lifestyle means that they have very low metabolic demands so they can survive on very little food. Their beak is specially adapted for grinding seeds, leaves, fruits, plants and pollen, and they have a particularly short gizzard as a result of this, as unlike other birds they don’t need this hind stomach structure to grind their food. Kakapos are well known for leaving so called ‘browse signs’ behind them as they forage; these are balls of indigestible fibre left behind when the parrot strips the most nutritious parts of the plant out.
The kakapo has evolved into an almost entirely nocturnal lifestyle. Studies of their anatomy have shown they have a similar eye shape to other nocturnal birds like nightjars and owls, but still with some similarities to other parrots. Structures in their brains related to vision are significantly smaller than they are in other parrots. Their retinas have morphology somewhere between a diurnal and nocturnal bird, suggesting the kakapos have evolved to fit into a crepuscular niche (this means active at dawn and dusk).
Kakapos are unique in yet another sense, in that they are the only flightless bird to use a lek breeding system. This involves a large group of males coming together to engage in competitive courtship rituals to entice females who come to watch and pick the best males out for breeding. Like a form of bird speed dating! Male Kakapos will spend a great deal of time excavating bowls, shallow depressions in the ground that are linked together by tracks that the birds will maintain. Males will sit in these bowls and let out loud booming noises, handily amplified by their carefully dug bowls. These ‘booms’ can be so loud that on a windy night, the sound can be carried as far as 5km away! That’s one way to grab a lady’s attention! Once a female has trundled her way to her noisy potential partner, the male will perform a courtship ritual where he will rock from side to side, click his beak and spread his wings and stomp back towards the female. If this little performance is successful, the female Kakapo will eventually lay 1-4 eggs, nesting on the ground with plant cover or inside the trunk of a hollow tree. The female unfortunately has to leave the eggs every night to forage for food, and this leaves the eggs vulnerable to predation, especially from invasive species like feral cats. After 30 days, the eggs will hatch, but the fledglings are still incredibly vulnerable in their ground dwelling nests. This reproductive biology is one of the reasons why Kakapos were almost driven to extinction and why they are still struggling back from that brink today.
A kakapo mother feeding her fledgling chicks (image from https://www.smithsonianmag.com/science-nature/going-to-extremes-69362142/
Cute, curious and critically endangered
Kakapo are classed as critically endangered by the IUCN redlist, with the most recent update on New Zealands’ Department of Conservation website putting the population at 197 individuals.
Unfortunately, Kakapos were doomed from the moment they came into contact with humans, firstly with Polynesian colonisation in the 1300’s, followed by European colonisation in the 1800’s. Due to their flight-lessness, curious nature and ground nesting the Kakapo was an easy target for Māori hunters and their dogs. The clearance of forests for settlements destroyed large areas of Kakapo habitat, and stowaway rats, those destructive invasive species, that came on board Polynesian ships preyed upon the eggs and chicks as they lay on the forest floor. This led to local extinction of Kakapos in the Tararua and Aorangi Mountain ranges, although the quirky little bird still thrived in the forested parts of the North and South Islands.
However, it was European colonisation that almost consigned this species to the history books, along with the dodo and the thylacine. Already fragmented and beginning to suffer the effects of genetic drift and inbreeding due to Polynesian hunting, the introduction of more invasive mammals and further destruction of habitat by Europeans pushed the Kakapo closer towards extinction. In the 1880’s this dire situation was worsened by the introduction of several species of mustelid, including stoats, ferrets, and weasels, to tackle the rabbit overpopulation New Zealand was suffering from. They preyed on the Kakapo and their eggs just as Polynesian introduced rats had done previously and by the 1890’s, the sharp decline was impossible to ignore, and the government stepped in, putting aside Resolution Island as a nature reserve in 1891. Richard Henry, a keen naturalist, was assigned as a caretaker of the rugged, remote island, and he soon realised the threats ground dwelling birds faced. He spent the next 14 years of his life catching and then transporting thousands of ground dwelling birds, like rheas and kakapos, across the choppy waters to Resolution Island, away from the jaws of furry predators and into the safety of the isolated reserve. It wasn’t especially hard; he found the rather dopey Kakapos could simply be picked up and stuffed in a sack without much protest or chasing. He was one of the first people to truly understand the breeding ecology of the Kakapo, and his studies laid the foundation for the conservation actions we see today. Unfortunately, his little Kakapo paradise came crumbling down when in 1900, boating tourists reported seeing a stoat on the beach of Resolution Island. Henry spent much of the next year attempting to catch the wily little mammal, all to no avail. The stoat was never caught, and it soon transpired a few stoats had swum across the water from the mainland and established a thriving population. Within 6 years, Henrys’ hard work was wiped out, and none of the Kakapos he saved were seen again.
Dedicated bird conservationist, Richard Henry, looking out from his Resolution Island home, probably thinking about how many more Kakapos he has to save. (image from https://www.atlasobscura.com/articles/richard-henry-kakapo-conservation)
Despite the precipitous declines elsewhere, the Kakapo kept a stronghold in Fiordland in the South of New Zealand until the 1930’s, when reports of the birds being seen or heard booming became scarcer and scarcer. By the 1950’s, the introduction of ship rats to the area had crippled the population and left just a few scattered, isolated populations in the most remote and inaccessible valleys. In 1970’s, conservation breeding programmes were initiated, but soon abandoned when it was discovered the lek breeding system of the kakapo. Instead, conservationists decided to establish a healthy population on a predator free island.
In 1989, the New Zealand Department of Conservation developed the Kakapo Recovery Programme, with the first job being to select several isolated islands on which to translocate the remaining kakapo that could be caught. Four offshore islands were chosen: Maud, Little Barrier, Codfish and Mana. All of the islands needed intensive management before the kakapo could be translocated there, to improve the vegetation on the island and eradicate any mammalian predators.
A map of New Zealand showing the key places in the conservation history of the Kakapo (Image from Powlesland et al, 2006)
Despite the Conservation Department keeping a close eye on the islands, in 1998 the continued presence of rats meant that Little Barrier Island and Mana Island had to be evacuated of birds, and they were moved to two new sanctuaries: Chalky Island and Anchor Island. Today, the kakapo only exist on these few islands, closely guarded.
Conservation Optimism
Kakapo are listed on appendix one of CITES, protecting them from all trade and they are legally protected in New Zealand and treated as a flagship animal, representative of their diverse bird life. Kakapos are watched closely; individuals are tracked with radio telemetry tags and during breeding season, infra-red cameras are placed by every nest to monitor them. As many as 61% of Kakapo eggs fail to hatch, and researchers are studying the reproductive biology of these endangered birds to understand why. A study from 2021 found that artificially inseminating Kakapo results in more breeding success, and this has been trialled a few times to improve hatching success and secure a safer future. When a Kakapo mother is struggling to successfully care for all her chicks, the caretakers will remove the eggs, incubate them and then hand rear them, which requires round the clock specialist care. The chicks are kept with their Kakapo brethren to prevent them imprinting on their human mothers. The hand reared chicks have a 100% survival rate, testament to the amazing skills of the conservationists that protect them. Like the ultimate form of couples matching, Kakapo are genetically sequenced and carefully paired to ensure maximum genetic diversity, as the birds have suffered significant genetic bottlenecks in the past as their numbers dropped so low and the populations became so isolated. However, there is some surprising positivity here; when researchers sequenced the entire Kakapo genome and compared this to historical mainland and current island populations, they found that overall, the island Kakapos are not as inbred as first thought and have fewer damaging mutations than expected. This is likely because the island populations suffered such dramatic drops in numbers that over time that inbreeding led to more serious, even fatal mutations that were gradually weeded out of the population. This is an encouraging sign for many endangered species; even long isolated, small island populations can recover genetically from populations crashes.
A tiny Kakapo chick being hand fed by a caretaker (Image from Jake Osborne, https://www.doc.govt.nz/our-work/kakapo-recovery/what-we-do/current-conservation/)
Supplementary feeding is also part of the conservation plan, and Kakapo are regularly given health checks including a weighing, blood test, parasite and injury check and replacement of the radio transmitter, with all the information being loaded into a national database that helps researchers track the history of each Kakapo and build more knowledge about the species.
There is intensive predator control around the Kakapo inhabited islands, with anti-predator controls like humane traps in place. Anything that goes onto the island, people, gear, food, boats and helicopters are quarantined and checked by well trained staff to ensure there is nothing that could threaten the delicate ecosystem on the islands.
The New Zealand Department of Conservation runs a Kakapo specific conservation department that works with scientists, conservationists and dedicated volunteers to enact the Kakapo Recovery Plan. Learn more about the history of the Kakapo and their plan for the future of this weird and truly fabulous bird on their website above. You can donate to support the programme and even adopt one of the Kakapos.
Awesome Videos
References
Atkinson, I.A.E. and Merton, D. (2006) ‘Habitat and diet of Kakapo in the Esperance Valley, New Zealand.’
Bergner, L.M. Dussex, N. Jamieson, I.G. and Robertson, B.C. (2016) ‘European colonisation, not Polynesian arrival, impacted population size and genetic diversity in the Critically Endangered New Zealand Kakapo.’ Journal of Heredity, 107(7).
Clout, M.N. and Merton, D.V. (1998) ‘Saving the kakapo: the conservation of the world’s most peculiar parrot.’ Bird Conservation International.
Cockrem, J.F. (2002) ‘Reproductive biology and conservation of the endangered kakapo in New Zealand.’ Avian and Poultry Biology Reviews
Corfield, J.R. Gsell, A.C. Brunton, D. Heesy, C.P. Hall, M.I. Acosta, M.L. and Iwaniuk, A.N. (2011) ‘Anatomical specialisations for nocturnality in a critically endangered parrot, the Kakapo.’ PLoS ONE, 6(8)
Eason, D.K. Elliott, G.P. Merton, D.V. Jansen, P.W. Harper, G.A. and Moorhouse, R.J. (2006) ‘Breeding Biology of Kakapo on offshore island sanctuaries.’ The Ornithological Society of New Zealand.’
Elliott, G.P. Merton, D.V. and Jansen, P.W. (2001) ‘Intensive management of a critically endangered species: the Kakapo.’ Biological Conservation, 99(1)
https://www.iucnredlist.org/species/22685245/129751169
https://www.doc.govt.nz/kakapo-recovery
Lloyd, B.D. and Powlesland, R.G. (1994) ‘The decline of the kakapo and attempts at conservation by translocation.’ Biological Conservation, 69(1)
Merton, D.V. Morris, R.B. and Atkinson, I.A.E (1984) ‘Lek behaviour in a parrot: the Kakapo of New Zealand.’ IBIS.
Powlesland, R. Merton, D. and Cockrem, J. (2006) ‘A parrot apart: the natural history of the Kakapo and the context of its conservation management.’ Environmental Science.
Savage, J.L. Crane, J.M.S. Kakapo Recovery Team and Hemmings, N. (2021) ‘Low hatching success in the critically endangered Kakapo is driven by early embryo mortality not infertility.’ Animal Conservation.
von Seth J, Foster Y, Kutschera VE, Guschanski K, Rhie A, Phillippy AM, Korlach J, Howe K, Chow W, Pelan S, Damas JD. (2021) ‘Population genomics of the critically endangered kakapo.’ Cell.
