A flightless, ground-dwelling parrot (Strigops habroptilus), native to New Zealand, also known as an owl parrot; face with owl-like array of radiating feathers; nocturnal; inhabits mountain forest; eats fruit, shoots, moss, and fungi; seriously endangered, they numbered just 86 in March 2005. (Family: Psittacidae.)
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?Kakapo Conservation status: Critical |
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Strigops habroptilus Gray, 1845 |
The Kakapo (Māori: kākāpō, meaning night parrot), Strigops habroptilus (from the Greek strix, genitive strigos: owl and ops: face; It is the only species in the genus Strigops and the tribe Strigopini, which is placed in the subfamily Psittacinae, or alternatively the kakapo forms a subfamily of its own, Strigopinae.
Kakapo are critically endangered, with only 86 living individuals known, all of whom are named. Prehistorically, the ancestral Kakapo migrated to the islands of New Zealand and, in the absence of mammalian predators, it lost the ability to fly. With Polynesian and European colonisation and the introduction of predators such as cats, rats, and stoats, almost all the Kakapo were wiped out. Conservation efforts began in the 1890s, but they were not very successful until the implementation of the Kakapo Recovery Plan in the 1980s. All surviving Kakapo are kept on two predator-free islands, Chalky Island in southwest Fiordland and Codfish Island/Whenuahou near Stewart Island/Rakiura, where they are closely monitored.
Physical description
Kakapo are large, rotund parrots: males measure up to 60 centimetres (24 in) and weigh between 3 and 4 kilograms (7–9 lb) at maturity. Kakapo are unable to fly, having short wings for their size and lacking the pronounced keel bone (sternum) that anchors the flight muscles of other birds. Unlike other land birds, Kakapo can accumulate large amounts of body fat to store energy.
Kakapo have moss-green feathers barred with black on the back, blending well with native vegetation. Kakapo have a facial disc of fine feathers, resembling the face of an owl;
The beak of the Kakapo is specially adapted for grinding food very finely. For this reason, Kakapo have very small gizzards compared to other birds of their size. Kakapo feet are large, scaly and, as in all parrots, zygodactyl (two toes face forward and two backward).
Kakapo have a well-developed sense of smell which complements their nocturnal lifestyle (Hagelin 2004). Kakapo can also discriminate among odours while foraging; One of the most striking characteristics of Kakapo is their pleasant and powerful odour, which has been variously described as like flowers and honey, an air freshener, or the inside of an antique violin case. Given the Kakapo's well-developed sense of smell this scent may be a social chemosignal. The smell has often led predators right to the relatively defenseless Kakapo.
Reproduction
Kakapo are the only parrots in the world that have a lek breeding system.
During the courting season, males leave their usual territories for hilltops and ridges where they each establish their own mating courts. These leks can be up to 7 kilometres (4 mi) from a Kakapo's usual territory and are an average of 50 metres (160 ft) apart within the lek arena.
Each court consists of a series of bowl-like depressions dug in the ground by the male, up to 10 centimetres (4 in) deep and long enough to fit the half-meter length of the bird.
To attract females, males make loud, low-frequency booming calls from their bowls by inflating a thoracic sac. The male Kakapo then stands up for a short while before again lowering his head, inflating his chest and starting another sequence of booms.
Females are attracted by the booms of the competing males; When in the presence of a female, males apparently become sexually excited, and may attempt to copulate with objects other than female Kakapo.
Female Kakapo lay between one and four eggs per breeding cycle. Kakapo eggs usually hatch within 30 days, bearing fluffy gray chicks that are quite helpless.
Since Kakapo are quite long-lived, they tend to enjoy an adolescence before beginning breeding. Although this is quite a long delay before they start to reproduce, Kakapo are thought to live at least 60 years, leaving plenty of time to perpetuate the species. Kakapo do not breed every year and have one of the lowest rates of reproduction among birds. Rimu mast occurs only every three to five years, so in rimu-dominant forest such as on Codfish Island, Kakapo breeding occurs as infrequently.
Ecology and behaviour
The ancestors of the Kakapo migrated to the islands of New Zealand millions of years ago. Before the arrival of humans, Kakapo were wildly successful;
Kakapo once ranged throughout the three main islands of New Zealand. In Fiordland, areas of avalanche and slip debris with regenerating and heavily fruiting vegetation such as five finger, wineberry, bush lawyer, tutu, hebes, and coprosmas became known as "Kakapo gardens".
Kakapo are primarily nocturnal, roosting under cover in trees or on the ground during the day and roving their territories at night. Though the Kakapo cannot fly, they are excellent climbers, ascending to the crowns of the tallest trees. Having lost the ability to fly, Kakapo have developed very strong legs. Kakapo are able to run at a fair speed, but cannot sustain their speed for long distances.
Kakapo are generally herbivorous, eating a wide variety of native plants, seeds, fruits, pollens and even the sapwood of trees. Kakapo have a distinctive habit of grabbing a leaf or frond with a foot and stripping the nutritious parts of the plant out with their beaks, leaving a ball of indigestible fiber, similar to the way humans eat only the tender parts of artichokes. The little clumps of plant fibers are a distinctive sign of the presence of Kakapo. Kakapo have also been observed to occasionally eat insects and other invertebrates.
Kakapo are naturally curious, and though they live solitary lives in remote places, they have been known to enjoy the occasional company of humans.
Like many parrots, Kakapo have a wide range of calls used for various purposes.
One behaviour that has not recently served the Kakapo well is their reaction to a predator or threat. When Kakapo feel threatened, they simply freeze, hoping to blend in with the vegetation that they so resemble.
Conservation
The population of Kakapo in New Zealand has been significantly reduced since human habitation of the country. The most successful scheme has been the Kakapo Recovery Plan which was implemented in 1989.
Human impact
The first factor in the decline of the Kakapo was the arrival of humans about a thousand years ago. Māori settlers from Polynesia hunted the Kakapo for food and for their skins and feathers, which were made into luxurious capes. With its flightlessness, strong scent and habit of freezing in the face of danger, the Kakapo was easy prey for Māori and the dogs they brought to the islands. Furthermore, the deliberate clearing of vegetation by Māori reduced the habitable range for Kakapo. Kakapo were extinct in many parts of the islands by the time Europeans arrived.
From the 1840s, European settlers cleared huge amounts of land for farming and grazing, further jeopardising the Kakapo and their habitat. They also brought more mammalian predators including cats, bigger species of rats and more dogs, all of which killed either adult or young Kakapo. Europeans knew little of the Kakapo until George Gray of the British Museum described it from a skin in 1845. Like Māori, early European explorers and their dogs fed on Kakapo. In the late 1800s, Kakapo 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 that Kakapo were declining and possibly on the way to extinction. They also preyed heavily on many native species including the Kakapo. Other browsing animals, such as introduced deer, also compete with Kakapo for food, and have caused the extinction of some preferred plant species.
Early protection efforts
In 1891, the New Zealand government set aside Resolution Island in Fiordland as a nature reserve and in 1894 appointed Richard Henry as caretaker. Seeing the value of a predator-free island such as Resolution Island, he began catching and moving Kakapo and kiwi from the mainland to Resolution. In six years, he moved over 200 Kakapo to Resolution Island. Sadly, by 1900 stoats had swum to Resolution Island, colonised it, and killed all the Kakapo there within 6 years.
In 1903, three Kakapo were moved from Resolution Island to the nature reserve of Hauturu/Little Barrier Island north-east of Auckland, but feral cats were present on the island and the Kakapo were never seen again. In 1912, three Kakapo were moved to another reserve, Kapiti Island north-west of Wellington. While most people's attention was understandably elsewhere, the Kakapo population continued to decline. By the 1920s, Kakapo were extinct on the North Island and their range and numbers on the South Island greatly reduced. By the 1940s, reports of Kakapo were becoming scarce.
New Zealand Wildlife Service
In the 1950s, the New Zealand Wildlife Service was established and began making regular expeditions to search for Kakapo, mostly in Fiordland and what is now the Kahurangi National Park in the northwest of the South Island. Finally, in 1958 a Kakapo was caught and released in the Milford Sound catchment area in Fiordland. In 1961 six Kakapo were captured, one being released and the other five transferred to the aviaries of the Mount Bruce Native Bird Reserve near Masterton in the North Island. In the next 12 years regular expeditions found few signs of Kakapo, indicating that numbers were continuing to decline. It was captured in 1967 and, despite optimism about improved techniques for keeping Kakapo in captivity, died the following year.
By the early 1970s, it was uncertain whether Kakapo had survived. In early 1974, two Kakapo were captured in the Milford Sound catchment and moved to Maud Island in the Marlborough Sounds at the north of the South Island.
At the end of 1974, searchers located several more male birds and made the first scientific observations of Kakapo booming. The observations led Don Merton to speculate for the first time that Kakapo had a lek breeding system. In 1976, four male Kakapo were discovered in the Transit Valley, the next catchment south of Milford Sound.
From 1974 to 1976, 14 Kakapo were discovered but all appeared to be males. However, even here, stoats were present and by 1976 Kakapo were gone from the valley floors and only a few males survived high on the most inaccessible parts of the cliffs.
Although Kakapo expeditions had been mounted in the South Island, and occasionally in the North Island, since 1951, no expedition went to Stewart Island/Rakiura until 1977. This was despite government workers seeing a Kakapo there and snatching feathers from it in 1949. In 1970, a deerhunter photographed a Kakapo there and reported it to a Forest Service officer who apparently ignored the report. The 1977 expedition found a track and bowl system on its first day and soon located several dozen Kakapo, raising hope that the population would include females.
It was realised at the same time that although Stewart Island/Rakiura was free of stoats and other mustelids, feral cats were killing Kakapo at an alarming rate. Over 1980 and 1981, three females and a male were moved to Maud Island to join Richard Henry, the only Fiordland bird still alive. Between 1977 and 1982, cats killed 50% of the Kakapo that had been identified on Stewart Island/Rakiura. They were joined there by Richard Henry and the three surviving Stewart Island birds from Maud Island.
Possums were eradicated from Codfish Island, off the north-west corner of Stewart Island/Rakiura, in 1987, and 10 females and 20 males were moved there from Stewart Island/Rakiura between 1987 and 1992. By 1995, the known world population of Kakapo had dropped to 50 individuals, of which just 19 were females.
Kakapo Recovery Plan
In 1989, a Kakapo Recovery Plan was developed and a Kakapo Recovery Group established to implement it. As no breeding had occurred on Hauturu/Little Barrier Island in the seven years birds had been there, supplementary feeding of some females there began.
It was five years before any more Kakapo fledged, when birds mated on Codfish Island in 1997. Richard Henry was returned from Hauturu/Little Barrier Island to Maud Island in 1996 and in 1998, he fathered three chicks, the first fledglings for many years with South Island genes.
While Codfish Island and Hauturu/Little Barrier Island were free of cats, mustelids, Black Rats and Brown Rats, both had the smaller Polynesian Rat. It was not initially known that Polynesian Rats too would predate Kakapo eggs and chicks, as well as competing with Kakapo for food. At the same time it was decided to move the Kakapo from Hauturu/Little Barrier Island to Maud Island, not only because of the rats but because only two young had fledged there, after supplementary feeding, and the rugged terrain made close management difficult. When birds were being captured on Hauturu/Little Barrier Island for removal in 1999, a female who had not been seen since 1984 was discovered incubating three eggs. In 1998, the Codfish Island population was moved to nearby Pearl Island for two years while rats were poisoned on Codfish Island.
In 2001, scientists predicted that rimu on Codfish Island would mast (fruit heavily) in the coming season, providing a stimulus to Kakapo breeding.
Rimu did not mast in the following two years and consequently Kakapo did not breed. In an attempt to get Kakapo breeding more frequently, a number of them have been moved to beech-dominant Chalky Island. Eighteen of the two-year-olds were moved from Codfish Island to Chalky Island in July 2004.
Current status
The surviving Kakapo population is intensively managed by the Kakapo Recovery Group in an attempt to preserve the species. The ongoing success of Kakapo conservation relies on the management of the reproduction of the remaining birds. He has a more yellow colouration than the other Kakapo and booms in a different "dialect" than the others. Early attempts used a fake female kakapo mounted on a radio-controlled toy car, which would approach a male in the midst of his lek display.
Females are given supplementary food at personal "feeding stations" in the hope that they will produce young every year, rather than just in mast years. Conservators employ many methods and devices to monitor Kakapo nests.
Though the future looks brighter with the increase in population since 1997 and the fledging of 24 chicks in 2002, Kakapo are still in an extremely perilous position as demonstrated by the sudden death in July 2004 of three of the 15 females hatched in 2002. Five chicks hatched, although one has since died, and one adult male Kakapo died in winter 2005. The Kakapo Recovery Group devised a more sophisticated feeding schedule;
If the birds continue to breed successfully, the next obstacle to future conservation efforts is the lack of a large predator-free island capable of holding more than 100 Kakapo, where the birds could look after themselves. In November 2005, plans were announced for a new wildlife sanctuary on the South Island mainland, to include many rare native species including Kakapo. The sanctuary, to be located at Orokonui, north of Dunedin, is scheduled for completion in 2007, and should create a large predator-free environment for the Kakapo.
Every known Kakapo has been given a name by Kakapo Recovery Programme officials. A detailed list of the individuals, and the parentage and age of the recently hatched chicks can be found at list of Kakapo.
The conservation of the Kakapo has made the species well known. Numerous books for adults and children and many documentaries detailing the plight of the Kakapo have been produced in recent years.
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