takahē

The South Island takahē (''Porphyrio hochstetteri'') is a flightless swamphen indigenous to New Zealand and the largest living member of the rail family. It is often known by the abbreviated name takahē, which it shares with the recently extinct North Island takahē. The two takahē species are also known as notornis.

Takahē were hunted extensively by Māori but was not named and described by Europeans until 1847, and then only from fossil bones. In 1850 a living bird was captured, and three more collected in the 19th century. After another bird was captured in 1898, and no more were to be found, the species was presumed extinct. Fifty years later, however, after a carefully planned search, South Island takahē were dramatically rediscovered in 1948 by Geoffrey Orbell in an isolated valley in the South Island's Murchison Mountains. The species is now managed by the New Zealand Department of Conservation, whose Takahē Recovery Programme maintains populations on several offshore islands as well as Takahē Valley. It has now been reintroduced to a second mainland site in Kahurangi National Park. Although South Island takahē are still a threatened species, their NZTCS status was downgraded in 2016 from Nationally Critical to Nationally Vulnerable. The population is 440 (as of October 2021) and is growing by 10 percent per year.

Discovery and naming

Anatomist Richard Owen was sent fossil bird bones found in 1847 in South Taranaki on the North Island by collector Walter Mantell, and in 1848 he coined the genus ''Notornis'' ("southern bird") for them, naming the new species ''Notornis mantelli''. The bird was presumed by Western science to be another extinct species like the moa.

Two years later, a group of sealers in Tamatea / Dusky Sound, Fiordland, encountered a large bird which they chased with their dogs. "It ran with great speed, and upon being captured uttered loud screams, and fought and struggled violently; it was kept alive three or four days on board the schooner and then killed, and the body roasted and ate by the crew, each partaking of the dainty, which was declared to be delicious." Walter Mantell happened to meet the sealers, and secured the bird's skin from them. He sent it to his father, palaeontologist Gideon Mantell, who realised this was ''Notornis'', a living bird known only from fossil bones, and presented it in 1850 to a meeting of the Zoological Society of London. A second specimen was sent to Gideon Mantell in 1851, caught by Māori on Secretary Island, Fiordland. (Takahē were well known to Māori, who travelled long distances to hunt them. The bird's name comes from the Māori verb ''takahi'', to stamp or trample.)

Only two more South Island takahē were collected by Europeans in the 19th century. One was caught by a rabbiter's dog on the eastern side of Lake Te Anau in 1879. It was bought by what is now the State Museum of Zoology, Dresden, for £105, and destroyed during the bombing of Dresden in World War II. Another takahē was caught by another dog, also on the shore of Lake Te Anau, on 7 August 1898; the dog, named 'Rough', was owned by musterer Jack Ross. Ross tried to revive the female takahē, but it died, and he delivered it to curator William Benham at Otago Museum. In excellent condition, it was purchased by the New Zealand government for £250 and was put on display; for many years it was the only mounted specimen in New Zealand, and the only takahē on display anywhere in the world.

After 1898, hunters and settlers continued to report sightings of large blue-and-green birds, described as "giant pukakis" (pūkeko or Australasian swamphens); one group chased but couldn't catch a bird "the size of a goose, with blue-green feathers and the speed of a racehorse". None of the sightings were authenticated, and the only specimens collected were fossil bones. The takahē was considered extinct.

Taxonomy and systematics

The third takahē collected went to the Königlich Zoologisches und Anthropologisch-Ethnographisches Museum in Dresden, and the Director Adolf Bernhard Meyer examined the skeleton while preparing his classification of the museum's birds, ''Abbildungen von Vogelskeletten'' (1879–95). He decided the skeletal differences between the Fiordland bird and Owen's North Island specimen were sufficient to make it a separate species, which he called ''Notornis hochstetteri'', after the Austrian geologist Ferdinand von Hochstetter.

Over the second half of the 20th century, the two ''Notornis'' species were gradually relegated to subspecies: ''Notornis mantelli mantelli'' in the North Island, and ''Notornis mantelli hochstetteri'' in the South. They were then incorporated into the same genus as the closely related Australasian swamphen or pūkeko (''Porphyrio porphyrio''), becoming a subspecies of ''Porphyrio mantelli''. Pūkeko are members of a widespread species of swamphen, but based on fossil evidence have only been in New Zealand for a few hundred years, arriving from Australia after the islands were first settled by Polynesians.

A morphological and genetic study of living and extinct ''Porphyrio'' revealed that North and South Island takahē were, as originally proposed by Meyer, separate species. The North Island species (''P. mantelli'', as described by Owen) was known to Māori as ''mōho''; it is extinct and only known from skeletal remains and one possible specimen. Mōho were taller and more slender than takahē, and share a common ancestor with living pūkeko. Takahē living in the South Island trace their ancestry back to a different lineage of ''Porphyrio porphyrio'', possibly from Africa, and represent a separate and earlier invasion of New Zealand by swamphens which subsequently evolved large size and flightlessness.

Rediscovery

Living South Island takahē were rediscovered in an expedition led by Invercargill-based physician Geoffrey Orbell near Lake Te Anau in the Murchison Mountains, on 20 November 1948. The expedition started when footprints of an unknown bird were found near Lake Te Anau. Two takahē were caught but returned to the wild after photos were taken of the rediscovered bird.

Description

The South Island takahē is the largest living member of the family Rallidae. Its overall length averages and its average weight is about in males and in females, ranging from . The lifespan of a takahē can range from 18 years in the wild or 22 in animal sanctuaries. Its standing height is around . It is a stocky, powerful bird, with short strong legs and a massive bill which can deliver a painful bite to the unwary. Although a flightless bird, the takahē sometimes uses its reduced wings to help it clamber up slopes.

South Island takahē plumage, beaks, and legs show typical gallinule colours. Adult takahē plumage is silky, iridescent, and mostly dark-blue or navy-blue on the head, neck, and underside, peacock blue on the wings. The back and inner wings are teal and green, becoming olive-green at the tail, which is white underneath. Takahe have a bright scarlet frontal shield and "carmine beaks marbled with shades of red". Their scarlet legs were described as "crayfish-red" by one of the early rediscoverers.

Sexes are similar; the females are slightly smaller, and may display frayed tail feathers when nesting. Chicks are covered with jet-black fluffy down when hatched, and have very large brown legs, with a dark white-tipped bill. Immature takahe have a duller version of adult colouring, with a dark bill that turns red as they mature.

South Island takahē are noisy. They have a non-directional warning ' call, which was described by the rediscoverers of takahē as someone "whistling to them over a .303 cartridge case", and a loud ' call. The contact call is easily confused with that of the weka (''Gallirallus australis''), but is generally more resonant and deeper.

Behaviour and ecology

The South Island takahē is a sedentary and flightless bird currently found in alpine grasslands habitats. It is territorial and remains in the grassland until the arrival of snow, when it descends to the forest or scrub. It eats grass, shoots, and insects, but predominantly leaves of '' Chionochloa'' tussocks and other alpine grass species. The South Island takahē can often be seen plucking a snow grass (''Danthonia flavescens'') stalk, taking it into one claw, and eating only the soft lower parts, which appears to be its favourite food, while the rest is discarded.

A South Island takahē has been recorded feeding on a paradise duckling at Zealandia. Although this behaviour was previously unknown, the related Australasian swamphen or pūkeko occasionally feeds on eggs and nestlings of other birds as well.

Breeding

The South Island takahē is monogamous, with pairs remaining together from 12 years to, probably, their entire lives. It builds a bulky nest under bushes and scrub, and lays one to three buff eggs. The chick survival rate is between 25% and 80%, depending on location.

Distribution and habitat

Although it is indigenous to swamps, humans have turned its swampland habitats into farmland, and the South Island takahē was forced to move upland into the grasslands. The species is still present in the location where it was rediscovered in the Murchison Mountains. Small numbers have also been successfully translocated to five predator-free offshore islands, Tiritiri Matangi, Kapiti, Maud, Mana and Motutapu, where they can be viewed by the public. Additionally, captive takahē can be viewed at Te Anau and Pukaha / Mount Bruce National wildlife centres. In June 2006 a pair of takahē were relocated to the Maungatautari Restoration Project. In September 2010 a pair of takahē (Hamilton and Guy) were released at Willowbank Wildlife Reserve – the first non-Department of Conservation institution to hold this species. In January 2011 two takahē were released in Zealandia, Wellington, and in mid-2015, two more takahē were released on Rotoroa Island in the Hauraki Gulf

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