It is endangered and has disappeared from much of its former range, though the re-introduction of North Island kākā at Zealandia in Wellington has led to an increasing population of the birds across the city.

The New Zealand kākā was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[4] Gmelin based his description on the "Southern brown parrot" from New Zealand that had been described in 1781 by the English ornithologist John Latham in his book A General Synopsis of Birds.

[7] The Māori language name kākā means "parrot", possibly related to kā, 'to screech'.

[7] The New Zealand kākā is a medium-sized parrot, measuring 45 cm (18 in) in length and weighing from 390 to 560 g (14 to 20 oz), with an average of 452 g (0.996 lb).

There is some evidence of sexual dimorphism in the North Island Kākā, with males tending to have larger bills than females.

[18]Therefore, a larger culmen is needed to access food sources such as wood-boring larvae which only males tend to seek out.

[20] The Kākā was once widespread throughout most of New Zealand; however, due to habitat modification, predation and resource competition from introduced animals, its distribution has now significantly decreased.

[21] From their reintroduction in 2002, North Island kākā continue to recolonise Wellington and a 2015 report showed a significant increase in their numbers over the preceding 12 years.

[22] New Zealand kākā are still considered common and easy to find in certain large forested areas of the South Island.

Kākā can be found in Rotoiti Nature Recovery Project, along the Milford Track and in the Eglinton Valley in Fiordland National Park.

[25] Their behaviour in group environments shows their high cognition by demonstrating their complex interactions through social play and communication.

[28] Large wood chips on the cavity floor can be further chewed and broken down to create a consistent base for the nestlings.

Before mating, the male kākā gently pushes the female with his foot, forehead and beak, then moves away.

[26] Play behaviour within parrots demonstrates complex cognition and an evolutionary history of living in social groups.

[26] This behaviour in kākā can be recognised as a distinctive hopping approach to a potential play partner as well as head cocking.

[26] New Zealand kākā typically feed on varieties of fruits, berries, seeds, flowers, buds, nectar, sap, plants and invertebrates.

[34][19] Kākā tend to consume more seeds, berries, and fruit when nectar and honeydew are low in winter, with their diet varying throughout the year and shifting focus during different seasons.

Sap feeding behaviour occurs most in mid to late winter and spring when there is a scarcity of flowers and other food sources which are prevalent during the summer months.

[34] This is evident on trees with larger damage and flatter, more broad bark removal compared to the sharp linear cuts of transverse gouges.

[34] Like tree sap, Kākā feed on Honeydew and nectar to access high-energy food sources to meet their energy requirements.

This is another high-energy resource created by scale insects that Kākā utilise in a similar way to sap and nectar using their bristle tongues to lap up the honeydew.

[19] The behaviour also tends to occur more often in males, potentially due to their larger beak size compared to females.

[19] New Zealand kākā are considered vulnerable, having greatly declined across their traditional range as a result of habitat loss, predation by introduced predators such as cats, rats, possums and stoats, and competition from wasps and bees for the honeydew excreted by scale insects.

A closely related species, Nestor productus, the Norfolk kākā, became extinct in 1851 for similar reasons.

[40][41] As cavity nesters with a long incubation period that requires the mother to stay on the nest for at least 90 days, New Zealand kākā are particularly vulnerable to predation.

[42] There is strong evidence that predation of chicks and females has led to a serious age and sex imbalance, even amongst ostensibly healthy populations.

[19] This includes threat displays such as raising the wings and facing the other bird while performing a loud call.

The Kākā plays a significant part in Māori mythology, with it often being seen as a symbol of power, authority, and prestige.

[45] Re-introduction of North Island kākā at Zealandia in Wellington, combined with conservation efforts, has led to a large increase in the population of the birds in the city.