Kākā

The New Zealand kākā (Nestor meridionalis) is a large species of parrot of the family Strigopidae found in native forests of New Zealand. The species is often known by the abbreviated name kākā, although it shares this name with the Norfolk kākā and Chatham kākā, both recently extinct. Two subspecies of New Zealand kākā are recognised. 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 lives in lowland and mid-altitude native forest. They tend to inhabit mature native forests with a more complex canopy. 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. Its strongholds are currently the offshore reserves of Kapiti Island, Codfish Island / Whenua Hou and Little Barrier Island. As of 2021, less than 50% of the kākā population was found on the mainland. It is breeding rapidly in the mainland island sanctuary at Zealandia with over 800 birds banded since their reintroduction in 2002. 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.

The New Zealand kākā lives in lowland and mid-altitude native forest. They tend to inhabit mature native forests with a more complex canopy. 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. Its strongholds are currently the offshore reserves of Kapiti Island, Codfish Island / Whenua Hou and Little Barrier Island. As of 2021, less than 50% of the kākā population was found on the mainland. It is breeding rapidly in the mainland island sanctuary at Zealandia with over 800 birds banded since their reintroduction in 2002. 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.

New Zealand kākā typically feed on varieties of fruits, berries, seeds, flowers, buds, nectar, sap, plants and invertebrates. They use their strong beaks to shred cones of kauri trees to obtain the seeds. It has a brush tongue with which it uses to feeds on nectar, and it uses its strong beak to dig out the grubs of the huhu beetle and to remove bark to feed on sap. They consume nectar from plant species such as kōwhai, flax, rātā, and pōhutukawa. Kākā, while feeding, often stand on one foot and use the other foot to manipulate food, like stripping the husk off of a fruit. This is a behaviour demonstrated in many other parrot species. Kākā feeding behaviour often varies depending on the season, with kākā switching to different resources based on seasonal availability. 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 ==== A common feeding behaviour frequently observed in kākā is sap feeding behaviour. 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. This behaviour is evident by the removal of bark from trees in areas populated by kākā. There are two types of bark removal strategies used by kākā. Firstly, there are transverse gouges made by the kākā's beak and are intended to break through the bark layer in a deep gouge, allowing the kākā to access the tree sap by lapping at the cut in the tree. These often appear on trees as small, long linear gouges wrapping around the branch or trunk of the tree. The second strategy is the removal of bark patches by scraping away layers of bark rather than gouging at it to reach the sap. This is evident on trees with larger damage and flatter, more broad bark removal compared to the sharp linear cuts of transverse gouges. Kākā have also been observed pulling bark from invasive pine trees (Pinus radiata) and native tree species like kauri. Sap feeding behaviour appears to be an important resource for kākā in many regions across New Zealand and for all individuals in kākā populations. It is likely a supplementary food for females before breeding but is also an important supplement to male kākā and kākā of all ages. Tree sap is a high-energy food source that can help kākā meet their energy requirements. Feeding observations were recorded in six kākā in a study of North Island kākā in pine tree (Pinus radiata) plantations, where it was found that 24% of their diet was made up of tree sap. This is an example of a specific North Island population that relied more on tree sap than other kākā populations. However, with reintroduced populations of kākā in Wellington, tree damage from kākā accessing tree sap has become more commonplace throughout the city. The behaviour also shows the kākā's high intelligence as often kākā, before sap feeding, test various points of a tree, looking for ideal locations like weak spots to begin removing bark. ==== Honeydew and nectar-feeding ==== Like tree sap, kākā feed on honeydew and nectar to access high-energy food sources to meet their energy requirements. Kākā have evolved a narrow and fimbriated tongue to lap up sap, honeydew and nectar. This specialised brush tongue seen in kākā helps kākā more efficiently consume sap, nectar and honeydew by allowing them to lap up these resources more easily. This adaptation of having a tongue covered in small hair-like structures help kākā utilise sap, honeydew and nectar; it is most pronounced in kākā compared to kea and kākāpō. Flower nectar makes up a large proportion of kākā's diet during the summer months when more flowers are in bloom. They use their bristle tongues to access the nectar within flowers and often use their foot to pull the flower closer or pull it off to access the nectar. Kākā also frequently utilise honeydew. This is another high-en…

New Zealand kākā are mainly arboreal and occupy mid-to-high canopy. They are often seen flying across valleys or calling from the top of emergent trees. They are very gregarious and move in large flocks that often include kea, where they are present. They are not obligate social animals and go between living in groups and being solitary, where they vocalise less. Their behaviour in group environments shows their high cognition by demonstrating their complex interactions through social play and communication. They are highly active at dawn and dusk and can sometimes be heard calling loudly. Kākā usually can be seen in groups of 3-5 and often forage alone but can form large groups around food sources like flowering or fruiting trees.

The New Zealand kākā nests in cavities in hollow trees. These trees are often mataī, rimu, tōtara, miro, hīnau and sometimes dead trees. The entrance hole is often three to six metres above the ground, but can be as low as ground level on predator-free offshore islands. The nest floor is lined with small wood chips and powder. This is intentionally created by the mother stripping wood and chewing wood chips from the cavity walls. Large wood chips on the cavity floor can be further chewed and broken down to create a consistent base for the nestlings. They lay eggs any time between September (late winter) and March (summer). Occasionally, in a good fruiting year, a pair can double clutch, often utilising the same nest hole for the second clutch and extending breeding into winter. They typically lay four eggs, though it can be up to eight, with two chicks fledging. Kākā eggs are white, slightly oval and have a rough surface. Only the female incubates the eggs, for about 24 days, and cares for the nestlings, but she is regularly fed by the male throughout breeding. Males feed the incubating female 8-12 times a day. Kākā nestlings leave the nest when approximately 70 days old, with nestlings as old as 11–20 days being left unattended for 20–70% of the night and 50–85% of the day. Both parents feed the chicks after they have fledged.

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. He placed it with the parrots in the genus Psittacus and coined the binomial name Psittacus meridionalis. The specific epithet meridionalis is Latin meaning "southern". 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. Latham had examined a preserved specimen in the Leverian Museum in London. The New Zealand kākā is now placed in the genus Nestor that was introduced in 1830 by René Lesson. There are two subspecies: the North Island kākā (Nestor meridionalis septentrionalis) and the South Island kākā (N. m. meridionalis), although more recent research has ruled out allopatric subspeciation. The Māori language name kākā means "parrot", possibly related to kā, 'to screech'. The genus Nestor contains four species, two of which are extinct: the New Zealand kākā (Nestor meridionalis), the kea (N. notabilis), the extinct Norfolk kākā (N. productus), and the extinct Chatham kākā (N. chathamensis). All four are thought to stem from a "proto-kākā", dwelling in the forests of New Zealand five million years ago. The closest living relative to the genus Nestor is the kākāpō or owl-parrot (Strigops habroptilus). Together, they form the parrot superfamily Strigopoidea, an ancient group that split off from all other Psittaciformes before their radiation. The New Zealand kākā's closest living relative is the kea; the kea and the New Zealand kākā became separate species 1.72 million years ago due to ecological divergence. This likely occurred due to changes in the climate during the Pleistocene that drove the New Zealand kākā to specialise in more forested environments and the kea to specialise in alpine and other habitats. This is why New Zealand kākā are found in more forested areas with complex canopies compared to the kea. There is also more genetic diversity within the New Zealand kākā when compared to both the kea and the kākāpō. 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). It is closely related to the kea, but has darker plumage and is more arboreal. The forehead and crown are greyish-white and the nape is greyish brown. The neck and abdomen are more reddish, while the wings are more brownish. Both sub-species have a strongly patterned brown/green/grey plumage with orange and scarlet flashes under the wings; colour variants that show red to yellow colouration especially on the breast are sometimes found. The calls include a harsh ka-aa and a whistling u-wiia. Kākā beak morphology also differs slightly from its closest relatives, the kea and kākāpō. The rhinotheca (upper part of the beak) of the kākā is narrower than the kākāpō and slightly longer. However, it is not as long and sharp as the rhinotheca seen in kea. Therefore, the kākā's bill is between the kea and kākāpō in length, sharpness, and width. There is some evidence of sexual dimorphism in the North Island kākā, with males tending to have larger bills than females. Male culmen lengths tended to be, on average, 13.6% and 12.4% larger than female culmen lengths. This is suggested to have evolved in male kākā due to the high proportion of provisioning the male kākā have to do for female kākā and hatchlings during the breeding season. Therefore, a larger culmen is needed to access food sources such as wood-boring larvae which only males tend to seek out.

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. New Zealand kākā are absolutely protected under New Zealand's Wildlife Act 1953. The species is also listed under Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) meaning international export/import (including parts and derivatives) is regulated. Under the New Zealand Threat Classification System (NZTCS), the North Island kaka is considered to be "At Risk", but with an increasing population, while the South Island kaka is considered "Threatened" and "Nationally Vulnerable".

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. He placed it with the parrots in the genus Psittacus and coined the binomial name Psittacus meridionalis. The specific epithet meridionalis is Latin meaning "southern". 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. Latham had examined a preserved specimen in the Leverian Museum in London. The New Zealand kākā is now placed in the genus Nestor that was introduced in 1830 by René Lesson. There are two subspecies: the North Island kākā (Nestor meridionalis septentrionalis) and the South Island kākā (N. m. meridionalis), although more recent research has ruled out allopatric subspeciation. The Māori language name kākā means "parrot", possibly related to kā, 'to screech'. The genus Nestor contains four species, two of which are extinct: the New Zealand kākā (Nestor meridionalis), the kea (N. notabilis), the extinct Norfolk kākā (N. productus), and the extinct Chatham kākā (N. chathamensis). All four are thought to stem from a "proto-kākā", dwelling in the forests of New Zealand five million years ago. The closest living relative to the genus Nestor is the kākāpō or owl-parrot (Strigops habroptilus). Together, they form the parrot superfamily Strigopoidea, an ancient group that split off from all other Psittaciformes before their radiation. The New Zealand kākā's closest living relative is the kea; the kea and the New Zealand kākā became separate species 1.72 million years ago due to ecological divergence. This likely occurred due to changes in the climate during the Pleistocene that drove the New Zealand kākā to specialise in more forested environments and the kea to specialise in alpine and other habitats. This is why New Zealand kākā are found in more forested areas with complex canopies compared to the kea. There is also more genetic diversity within the New Zealand kākā when compared to both the kea and the kākāpō.