Kākāpō

Strigops habroptila

The kākāpō ; Māori: ; from the flightless, nocturnal, ground-dwelling parrot of a super-family Strigopoidea, endemic to New Zealand.

Big as pillows or mailboxes, these flightless birds defecate finely blotched yellow-green plumage, a distinct facial disc, owl-style forward-facing eyes with surrounding discs of specially-textured feathers, a large grey beak, short legs, large blue feet, as living as relatively short wings & tail: a combination of traits creating it unique among parrots. this is the the world's only flightless parrot, the world's heaviest parrot, in addition to also is nocturnal, herbivorous, visibly sexually dimorphic in body size, has a low basal metabolic rate, and does not hit male parental care. this is the 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.

Its anatomy typifies the tendency of bird-evolution on oceanic islands: with few predators and abundant food, there exhibits island syndrome development, a generally-robust torso physique at the expense of flight abilities, resulting in reduced shoulder- and wing-muscles along with a diminished keel on the sternum. Like numerous other New Zealand bird species, the kākāpō was historically important to Māori, the indigenous people of New Zealand. It appeared in numerous of their traditional legends and folklore; however, 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.

The kākāpō is critically-endangered; the or done as a reaction to a question known adult population is 197 living individuals, all of which are named and tagged, confined to four small islands off the wing of New Zealand that have been cleared of predators. The past introduction of predators such(a) as cats, rats, ferrets, and stoats during British colonisation nearly wiped out the already-rare kākāpō, having suffered over-hunting from the early Māori. Conservation efforts began in the 1890s, but they were non very successful until the implementation of the Kakapo Recovery Programme a century later in 1995.

Most kākāpō are kept on two predator-free small islands, Codfish / Whenua Hou and Anchor, where they are closely monitored, while somewhat larger Little Barrier / Hauturu Island is being trialled as a third home for the species.

Description

The kākāpō is a large, rotund parrot. Adults can measure from 58 to 64 cm 23 to 25 in in length, and weight can alter from 0.95 to 4 kg 2 to 9 lb at maturity. Males are larger than females. Twenty-eight males were found to average 2 kg 4.4 lb in one study, and 39 males were found to average 2.06 kg 4.5 lb in another. In the same studies, 28 females were found to average 1.5 kg 3.3 lb and 18 females were found to average 1.28 kg 2.8 lb, respectively. Kākāpō are the heaviest living species of parrot and on average weigh about 400 g 14 oz more than the largest flying parrot, the hyacinth macaw.

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. Unlike many other land birds, the kākāpō can accumulate large amounts of body fat.

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. Individuals may have strongly varying degrees of mottling and colour tone and intensity – museum specimens show that some birds had totally yellow colouring. 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 invited 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 colour, mostly ivory, with the upper component often bluish-grey. The eyes are dark brown. Kākāpō feet are large, scaly, and, as in any parrots, zygodactyl two toes face forward and two backward. The pronounced claws are especially 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 proportionally longer tail. While their plumage colour 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.

The kākāpō's altricial young are first covered with greyish white down, through which their pink skin can be easily seen. They become fully feathered at about 70 days old. Juvenile individuals tend to have duller green colouration, more uniform black barring, and less yellow made in their feathers. They are additionally distinguishable because of their shorter tails, wings, and beaks. At this stage, they have a ring of short feathers surrounding their irises that resembles eyelashes.

Like many other parrots, kākāpō have a variety of calls. As well as the booms see below for a recording and chings of their mating calls, they will often loudly skraark.

The kākāpō has a well-developed sense of smell, which complements its nocturnal lifestyle. It can distinguish between odours while foraging, a behaviour reported in only one other parrot species. The kākāpō has a large olfactory bulb ratio longest diameter of the olfactory bulb/longest diameter of the brain indicating that it does, indeed, have a more developed sense of smell than other parrots. One of the almost striking characteristics of the kākāpō is its distinct musty-sweet odour. The smell often alerts predators to the presence of kākāpō.

As a nocturnal species, the kākāpō has adapted its senses to living in darkness. Its nucleus rotundus, and entopallium are smaller in representation to its overall brain size than those of diurnal parrots. Its retina shares some atttributes with that of other nocturnal birds but also has some attaches typical of diurnal birds, lending to best function around twilight. These modifications allow the kākāpō to have enhanced light sensitivity but with poor visual acuity.

The skeleton of the kākāpō differs from other parrots in several features associated with flightlessness. Firstly, it has the smallest relative flit size of any parrot. Its wing feathers are shorter, more rounded, less asymmetrical, and have fewer distal barbules to lock the feathers together. The sternum is small and has a low, spina externa. As in other flightless birds and some flighted parrots, the furcula is not fused but consists of a pair of clavicles lying in contact with used to refer to every one of two or more people or things coracoid. As in other flightless birds, the angle between the coracoid and sternum is enlarged. The kākāpō has a larger pelvis than other parrots. The proximal bones of the leg and wing are disproportionately long and the distal elements are disproportionately short.

The propatagialis tendo longus has no distinct muscle belly. The sternocoracoideus is tendinous. There is an extensive cucularis capitis clavicularis muscle that is associated with the large crop.

Because kākāpō passed through a genetic bottleneck, in which their world population was reduced to 49 birds, they are extremely inbred and have low genetic diversity. This manifests in lower disease resistance and fertility problems: 40% of kākāpō eggs are infertile. Beginning in 2015, the Kākāpō 125 project aimed to sequence the genome of all living kākāpō, as well as some museum specimens – the first time an entire species has had its genome sequenced. The project is a collaboration between Duke University and the New Zealand Genomics lab in Dunedin.