Kakapo

## Description

The kākāpō (Strigops habroptilus) is a species of large, flightless, nocturnal parrot found only in New Zealand. It is the world's only flightless parrot, the world's heaviest parrot, and also is nocturnal, herbivorous, visibly sexually dimorphic in body size, has a low basal metabolic rate, and does not have male parental care. It is the only parrot to have a polygynous lek breeding system. It is also possibly one of the world's longest-living birds, with a reported lifespan of up to 100 years. Like many other New Zealand bird species, the kākāpō was historically important to Māori, the indigenous people of New Zealand. It appeared in many of their traditional legends and folklore. It was also heavily hunted and was used as a resource by Māori (both for its meat and for its feathers, which were used to make highly-valued pieces of clothing). Rarely, Kākāpō were kept as pets.

## Appearance

The kākāpō cannot fly, having relatively short wings for its size and lacking the keel on the sternum (breastbone), where the flight muscles of other birds attach. It uses its wings for balance and to break its fall when leaping from trees. The upper parts of the kākāpō have yellowish moss-green feathers barred or mottled with black or dark brownish grey, blending well with native vegetation. The breast and flank are yellowish-green streaked with yellow. The belly, undertail, neck, and face are predominantly yellowish streaked with pale green, and weakly mottled with brownish-grey. Because the feathers do not need the strength and stiffness required for flight, they are exceptionally soft, giving rise to the specific epithet habroptilus. The kākāpō has a conspicuous facial disc of fine feathers resembling the face of an owl; thus, early European settlers called it the "owl parrot". The beak is surrounded by delicate feathers which resemble vibrissae or "whiskers"; it is possible kākāpō use these to sense the ground as they walk with its head lowered, but there is no evidence for this. The mandible is variable in color, mostly ivory, with the upper part often bluish-grey. The eyes are dark brown. Kākāpō feet are large, scaly, and, as in all parrots, zygodactyl (two toes face forward and two backward). The pronounced claws are particularly useful for climbing. The ends of the tail feathers often become worn from being continually dragged on the ground. Females are easily distinguished from males as they have a narrower and less domed head, narrower and proportionally longer beak, smaller cere and nostrils, more slender and pinkish grey legs and feet, and a proportionally longer tail. While their plumage color is not very different from that of the male, the toning is more subtle, with less yellow and mottling. Nesting females also have a brood patch of bare skin on the belly.

## Distribution

Before the arrival of humans, the kakapo was distributed throughout both main islands of New Zealand. Today they can be found only on islands free of predation; these are Codfish, Anchor, and Little Barrier Islands. Kakapo lived in a variety of habitats, including tussocklands, scrublands, and coastal areas. They also inhabited forests dominated by podocarps, beeches, tawa, and rata. These birds seem to have preferred broadleaf or mountain beech and Hall's tōtara forest with mild winters and high rainfall, but they were not exclusively forest-dwelling. Kakapos are now confined to islands free of predation. All birds that were transferred to predator-free islands have adapted well to any changes in the environment and food plants.

## Behavior

Kakapos are primarily nocturnal; they roost undercover in trees or on the ground during the day and move around their territories at night. Though kakapos cannot fly, they are excellent climbers, ascending to the crowns of the tallest trees. They can also "parachute" - descending by leaping and spreading their wings. In this way, they may travel a few meters at an angle of less than 45 degrees. On the ground, they move with a rapid "jog-like" gait by which they can move several kilometers. Kakapos are curious by nature and have been known to interact with humans; however, they are not social birds. When they feel threatened, kakapos freeze so that they are more effectively camouflaged in the vegetation their plumage resembles. Like many other parrots, kakapos have a variety of calls. As well as the 'booms' and 'chings' of their mating calls, they will often loudly 'skraark'.

## Diet

Kakapos are herbivores (frugivores, granivores, folivores). They eat native plants, seeds, fruits, pollen, and even the sapwood of trees.

## Reproduction

Kakapos are polygynous and don't form pairs; males and females meet only to mate. These birds are the only flightless birds that have a lek breeding system. Males loosely gather in an arena and compete with each other to attract females. During the courting season, males leave their home ranges for hilltops and ridges where they establish their own mating courts and remain there throughout the courting season. At the start of the breeding season, males will fight to try to secure the best courts. They confront each other with raised feathers, spread wings, open beaks, raised claws, and loud screeching and growling. Females listen to the males as they display, or "lek". They choose a mate based on the quality of his display; they are not pursued by the males in any overt way. Once a female enters the court of one of the males, the male performs a display in which he rocks from side to side and makes clicking noises with his beak. After mating, the female returns to her home territory to lay eggs and raise the chicks. The male continues booming in the hope of attracting another female. Kakapos do not breed every year, but usually every 2-4 years. Breeding occurs only in years when trees mast (fruit heavily), providing a plentiful food supply. The female lays 1-4 eggs per breeding cycle. She nests on the ground under the cover of plants or in cavities such as hollow tree trunks. The female incubates the eggs faithfully but is forced to leave them every night in search of food. The eggs usually hatch within 30 days, bearing fluffy grey chicks that are quite helpless. After the eggs hatch, the female feeds the chicks for 3 months, and the chicks remain with the female for some months after fledging. Chicks leave the nest at approximately 10 to 12 weeks of age. As they gain greater independence, their mother may feed them sporadically for up to 6 months. Female kakapos usually reach reproductive maturity at 9 years of age.

## Population

### Population threats

Kakapos were once New Zealand's third most common bird and they were widespread on all three main islands. The first factor in the decline of the species was the arrival of humans. Maori hunted the kakapo for food and for their skins and feathers. Its eggs and chicks were also preyed upon by the Polynesian rat or kiore, which the Māori brought to New Zealand as a stowaway. Furthermore, the deliberate clearing of vegetation by Māori reduced the habitable range for kakapo. Although these birds were reduced by Māori settlement, they declined much more rapidly after European colonization. Beginning in the 1840s, Pākehā settlers cleared vast tracts of land for farming and grazing, further reducing kakapo habitat. They brought more dogs and other mammalian predators, including domestic cats, black rats, and stoats. Early European explorers and their dogs also ate kakapo. In the late 19th century, these birds became well-known as a scientific curiosity, and thousands were captured or killed for zoos, museums, and collectors. From at least the 1870s, collectors knew the kakapo population was declining and their prime concern was to collect as many as possible before the bird became extinct.

### Population number

According to the IUCN Red List, in 2018 the total Kakapo population size was 149 individuals. Currently, this species is classified as Critically Endangered (CR) on the IUCN Red List but its numbers today are increasing.

## Fun Facts

The common English name "kakapo" comes from the Māori "kākāpō" where "kākā" is "parrot" and "pō" - "night".

Kakapo feet are large, scaly, and, as in all parrots, zygodactyl; it means two toes face forward and two backward. Their claws are also pronounced which is particularly useful for climbing.

The kakapo has a well-developed sense of smell, which complements its nocturnal lifestyle. It can distinguish between odors while foraging, and it does, indeed, have a more developed sense of smell than other parrots.

One of the most striking characteristics of the kakapo is its distinct musty-sweet odor. This smell often alerts predators to the presence of the bird.

When foraging, kakapos tend to leave crescent-shaped wads of fiber in the vegetation behind them, called "browse signs".

Kakapo chicks are very playful. They like to play fighting in which one bird will often lock the neck of another under its chin.

The kakapo was a very successful species in pre-human New Zealand and was well adapted to avoid the birds of prey which were their only predators. As well as the New Zealand falcon, there were two other birds of prey in pre-human New Zealand: Haast's eagle and Eyles' harrier. All these raptors soared overhead searching for prey in daylight, and to avoid them the kakapo evolved camouflaged plumage and became nocturnal.

The kakapo was regarded as an affectionate pet by the Māori. This was corroborated by European settlers in New Zealand in the 19th century, among them George Edward Grey. He once wrote in a letter to an associate that his pet kakapo's behavior towards him and his friends was "more like that of a dog than a bird".