Kākāpō

Name and taxonomy

George Robert Gray described and illustrated the bird in 1845. He made a new genus for it and named it Strigops habroptilus. Strigops joins the Greek words for owl and face. Habroptilus joins the words for soft and feather. The type locality was later fixed at Dusky Sound in the South Island.

The Māori name joins kākā, a parrot, and pō, the night. The word is the same in the singular and the plural. New Zealand English now writes it with macrons over the long vowels. Ornithologists argued for decades over the ending of the scientific name. The main checklists returned to habroptilus in 2024.

Evolution and relatives

The kākāpō sits in the family Strigopidae with the kea and the kākā. All three birds are found only in New Zealand. That family branched off before the other parrot families did. The split happened 33 to 44 million years ago. The kākāpō and the two Nestor parrots parted 27 to 40 million years ago.

Older writers linked the bird to the ground parrots of Australia. Molecular work rejected that idea. The similar colour probably evolved twice in two ground-living lines. Island life gave the bird a heavy trunk and tiny wing muscles. The keel on the breastbone shrank, since no flight muscles pull on it.

Appearance

The upper feathers are moss green, barred and mottled with black and dark grey. The breast and flanks are yellowish green streaked with yellow. The belly and face are mostly yellowish with pale green streaks. The pattern hides the bird well in native vegetation. The feathers are exceptionally soft, because they never need flight stiffness.

Adults measure 58 to 64 cm long, with a wingspan of about 82 cm. Males average 2 kg and females about 1.5 kg. A kākāpō outweighs the hyacinth macaw by roughly 400 grams on average. The feet are large and scaly, with two toes forward and two back. Pronounced claws make this heavy bird a good climber.

Fine feathers ring the beak like whiskers. The facial disc is the feature that earned the name owl parrot. Females have a narrower head and a proportionally longer beak and tail. Chicks wear greyish white down and are fully feathered at about 70 days. Young birds look duller, with more even black barring and shorter tails.

Habitat and range

Before people arrived, the kākāpō lived across both main islands. Tussockland, scrub, coast and several kinds of forest all held birds. It survived hot North Island summers and cold Fiordland winters. Researchers therefore call it a habitat generalist. It seems to have preferred broadleaf, beech and tōtara forest.

Fossils suggest it was once the third most common bird in the country. Slip and avalanche ground in Fiordland grew thick fruiting shrubs. Those patches became known as kākāpō gardens. The bird had gone from the North Island by about 1930. The final Fiordland population died out towards the end of the 1980s.

Every kākāpō alive now lives on managed ground. Whenua Hou and Anchor Island hold most of them. Four males went to Sanctuary Mountain Maungatautari in 2023. That was the first mainland population in almost 40 years. Resolution Island has been cleared of stoats for a future release.

Diet and feeding

The kākāpō eats only plants. Shoots, leaf buds, roots, rhizomes and tubers all appear in the diet. It also takes seeds, nuts, berries, fruit, pollen, moss and fungi. A study in 1984 listed 25 plant species as food. Work on preserved droppings added 67 more native plant genera.

Rimu fruit is the favourite. In a heavy rimu year the bird will eat almost nothing else. The beak grinds food finely, so the gizzard stayed small. Bacteria in the fore-gut are thought to help ferment plant matter. The bird leaves crescent-shaped wads of chewed fibre behind it.

Those wads are called browse signs, and they show where a bird has fed. A kākāpō can store large amounts of body fat, which few land birds do. Flightlessness keeps its energy demand low. It survives on very little food when it has to.

Behaviour and social life

The kākāpō is solitary and active at night. It roosts by day in trees or in shallow burrows among roots. It walks with a jog-like gait and can cover several kilometres. A nesting female may make two return trips a night to food 1 km away. A male may walk 5 kilometres from his range to a mating arena.

It climbs well and reaches the crowns of the tallest trees. It uses the wings for balance and to break a fall. It can parachute down at an angle of less than 45 degrees. Lighter females glide across gaps of 3 to 4 metres. Only 3.3 per cent of its mass is chest muscle.

A resident bird warns an intruder off with a loud skraak. Young birds play-fight and lock one another's necks under the chin. Rangers report that individual birds have distinct personalities. The species is curious and has often approached people.

Communication and senses

A male booms to draw a female to his court. The call sits below 100 hertz, which carries a long way. He inflates a sac in the chest and starts with low grunts. After about 20 booms he gives a high metallic ching. The sound reaches a kilometre on a still night, and 5 kilometres in wind.

Both sexes also give a loud high skraak. Booming can run for six to eight hours a night. A male may keep that up for more than four months in a breeding year. No other parrot has an inflatable chest sac of this kind.

The kākāpō has a strong sense of smell, which is rare among parrots. Its olfactory bulb is large in proportion to the brain. It can tell odours apart while it is feeding. The bird itself has a musty-sweet smell that predators follow. Its eyes suit twilight, with good light sensitivity and poor sharpness.

Reproduction and life cycle

The kākāpō is the only flightless bird with a lek breeding system. Males gather on hilltops and ridges and compete for the best courts. Rivals face off with feathers raised, beaks open, claws up and loud screeching. A fight can injure a bird or even kill it. Courts sit about 50 metres apart inside the arena.

Each male digs saucer-shaped bowls up to 10 centimetres deep. He places them beside rocks, banks or trunks, which reflect the sound. Tracks connect the bowls and may run 50 metres along a ridge. He clears every bowl and track of loose debris. Very few birds anywhere build their own lek in this way.

A female walks in, listens, and chooses on the strength of the display. The male rocks from side to side and clicks his beak. He spreads his wings and backs towards her. Mating can last 40 minutes or more, and then the two part. He forms no bond and gives no help with the young.

The female lays 1 to 4 eggs in a burrow or a hollow trunk. They hatch in about 30 days, and the chicks are helpless. She must leave every night to feed, which exposes the nest. Chicks leave the nest at about 10 to 12 weeks. Breeding follows a heavy rimu year, so it happens every two to four years.

Predators and threats

Before people came, only birds of prey hunted the kākāpō. Haast's eagle, Eyles' harrier and the New Zealand falcon all hunted by day. The bird answered with camouflage, night habits and freezing when alarmed. The laughing owl still caught some of them at night. Bones in owl deposits on Canterbury cliffs prove it.

Mammals hunt by scent, so freezing became useless. The strong smell of a kākāpō leads a stoat or a cat straight to it. Polynesian rats took eggs and chicks from the earliest settlement onwards. Cats on Stewart Island were killing 56 per cent of the birds a year. Intensive cat control began there in 1982.

Disease is now a serious risk in so small a population. An outbreak of aspergillosis on Whenua Hou in 2019 infected 21 birds. Nine of them died, and over 50 birds went to veterinary centres. Inbreeding is the other problem, and 61 per cent of eggs fail to hatch. The species passed through a bottleneck of 49 birds.

Population and conservation

The species was down to 51 birds in 1995. The Kākāpō Recovery Programme started that year and still runs. Every bird was moved to islands cleared of predators. Maud, Little Barrier, Codfish and Mana were the first four chosen. Anchor Island and Chalky Island later replaced two of them.

Rangers give the females extra food in a rimu year. Diet shifts the sex ratio of the chicks, so feeding is measured carefully. Eggs are often taken from a nest for artificial incubation. Cameras and data loggers watch every nest. Chicks are moved between nests when a mother cannot cope.

The population passed 100 for the first time in 2009. A record season in 2019 fledged 72 chicks. Numbers reached 252 in 2022 and slipped to 243 by 2024. Ninety chicks fledged in 2026, which lifted the total to 325. The programme aims for 150 breeding females.

Relationship with humans

Māori hunted the kākāpō for meat, skins and feathers. Hunters used snares, pitfall traps and dogs, mostly after dark. Booming males were easy to find in a breeding year. The meat was cooked in a hāngī or in gourds of hot oil. Ngāi Tahu hunters packed the preserved flesh in tōtara bark or in kelp.

Feathers went into cloaks that needed up to 11,000 of them. The garments were warm and beautiful, and people treated them as taonga. One complete kākāpō feather cloak survives, in a museum in Scotland. An old saying mocked anyone who felt cold while wearing such a cloak. Feathers also decorated the heads of taiaha, but came off before a fight.

Europeans killed thousands for zoos, museums and private collections. Most captured birds died within months. Collectors knew the species was failing, and raced to take more. Richard Henry moved over 200 birds to Resolution Island from 1894. Stoats swam across and wiped out that population within six years.

In culture and myth

Māori tradition holds a rich body of kākāpō belief. The bird breeds only in a heavy fruiting year, which looked like foresight. Stories say it dropped hinau and tawa berries into pools to keep them. The practice of storing food in water is credited to the bird.

Māori also kept the kākāpō as an affectionate pet. George Edward Grey wrote that his bird behaved more like a dog. Ngāi Tahu treat the species as a taonga, a treasure.

Television and radio made the bird famous well beyond New Zealand. Gerald Durrell filmed it for the BBC in 1962. Douglas Adams and Mark Carwardine sought it for Last Chance to See. Stephen Fry returned to Codfish Island with Carwardine in 2009. A male called Sirocco then tried to mate with Carwardine's head on camera.

That clip reached millions and made Sirocco a conservation spokes-bird in 2010. Sirocco also inspired the party parrot animation used in chat apps. New Zealand voted the kākāpō bird of the year in 2008 and again in 2020. A mobile game later raised support for the recovery work.