Takahe in a natural setting in Dunedin! Who would ever have thought it possible?
Two of these endangered birds - flightless giant rails - will soon make themselves at home at Orokonui Ecosanctuary. The species disappeared from around the Dunedin area well before Europeans arrived, and was probably waning in the time of early Maori settlement.
Large and slow-breeding, takahe (Porphyrio hochstetteri) look similar to pukeko, the common native swamp hen, which can still fly when pushed.
Ancestors of takahe lost the power of flight in a land without mammalian predators, and evolved to more than double the size and weight of pukeko.
Takahe weigh in at 2kg to 3.5kg (males are heavier), they stand about 12cm taller than pukeko, and their bill, legs and feet are much sturdier.
The takahe colour scheme resembles that of pukeko - an indigo head, neck and breast, a metallic green back and red bill, legs and feet - but more colourful. The size of the bill is remarkable.
Whereas pukeko thrive, takahe are classified as "nationally critical", with only about 260 remaining. Like many of New Zealand's ancient endemic birds, takahe are notoriously slow breeders. They breed only once a year and raise only one or two chicks from up to three eggs laid. Pukeko lay four to six eggs and they can have two or three broods a year.
Takahe, however, live longer - up to about 20 years.
In prehistoric times, they were distributed widely across mainland New Zealand but most live now in remote mountain valleys in Fiordland, their last stronghold. They were hailed as a species brought back from the dead when "rediscovered" in the Murchison Mountains in 1948.
Takahe love feeding on snow tussocks, being equipped with a stout bill that is well adapted to strip the tussock's fine fronds.
At Orokonui, snow tussocks newly planted near the open grassy spaces of the upper areas of the ecosanctuary should provide them with a good habitat. They will be confined to a temporary enclosure initially, to get them used to Orokonui conditions.
The two birds are from Maud Island in the Marlborough Sounds, which has been a refuge for small numbers of takahe transferred from the Fiordland area. Their role at Orokonui will be as ambassadors for the species. It is hoped they will raise awareness of the plight of takahe and public support for recovery efforts. Since 2005, Mitre 10 has been the main sponsor of the takahe recovery programme.
We hope they will feel at home in the upper reaches of Orokonui, close to 300m above sea level. Through winter they will have lush bush bordering the open areas for shelter and food, such as fern rhizomes.
The takahe are going to be a big attraction for visitors once they have settled in. Their calls are similar to those of weka but deeper and more piercing. The contact call is "coo-eet" and pairs may duet. When alarmed they utter a deep "oomf".
In the past 200 years, takahe have declined in number and range, virtually to the brink of extinction.
In 1981, the population was estimated at 112. Predation by stoats and competition with red deer for food are thought to be the main factors in their decline in modern times.
During the 1980s, a captive rearing unit was established for takahe at Burwood Bush near Te Anau, using eggs and chicks from Fiordland. About half of the population lives in the Murchison Mountains of Fiordland, with the remaining birds in a fenced reserve at Burwood Bush and in small numbers on island sanctuaries such as Kapiti, Tiritiri Matangi, Maud and Mana. There is also a pair of takahe at each of the mainland sanctuaries of Zealandia (Wellington) and Maungatautari (south Waikato), where there has been at least one successful breeding attempt.
University of Otago zoologist Dr Ian Jamieson, who has studied the species and is a member of the Takahe Recovery Group, says the takahe is one of our native species most at risk because it is extremely difficult to manage its threats.
While many of our threatened forest species of birds can be secured on "predator-free" island sanctuaries, takahe require large grassland areas, not typically abundant on our forested offshore islands.
Takahe require relatively large home ranges and breeding territories and the islands are often too small to sustain large numbers. For this reason Orokonui Ecosanctuary can host only a few birds.
Nevertheless, Dr Jamieson says Orokonui can play a vital role as an advocacy site, since the opportunity to see takahe in their remaining native habitat in alpine Fiordland is very limited.
Unlike many of our threatened species, the main hope for a large, viable population of takahe is on the mainland, where there are still large areas of native grasslands.
The key to success for that plan is the ability to limit introduced predators, such as stoats, to low densities over large areas of the landscape. Orokonui's new takahe can play an important role in setting the stage to educate the public about that crucial conservation message.
• Neville Peat is a Dunedin writer. He chairs Orokonui Ecosanctuary's trust board.
