Orokonui Ecosanctuary is preparing to receive a spectacular new species, as Neville Peat reports.
Rarest, largest and most attractive - the superlative Otago skink is a star among the New Zealand native lizard community.
And next month Orokonui Ecosanctuary will welcome a group of these amazing skinks into an enclosure inside the predator fence.
The Otago skink Oligosoma otagense, an ancient species found only in Otago, is listed as nationally critical, the same threat classification as kakapo.
Since European settlement, the species has been reduced to less than 10% of its former range. They were recorded as far west as Queenstown.
The catastrophic decline has occurred through habitat loss, in particular the conversion of shrubland and grassland to pasture across inland Otago's hills and valleys, and an invasion of predatory introduced species dating back to the 19th century.
Today, the main refuges for the Otago skink are in the Macraes and Nenthorn areas of inland Otago.
There are small numbers around southern Strath Taieri. The population at large is estimated at fewer than 2000 individuals.
A disjunct and critically endangered group lives in the Lindis and Hawea areas - fewer than 30 individuals. Genetic studies suggest these western Otago skinks diverged from the eastern populations 3.7 million years ago.
There is a protected small group near Alexandra at the Mokomoko Dryland Sanctuary, a relatively new predator-fenced reserve (3ha).
This project was developed by the Central Otago Ecological Trust. The Otago skink, closely related to the grand skink Oligosoma grande, is the larger of the two species, reaching 30cm in length, including tail, and 71g in weight.
They give birth to two or three live young in late summer or early autumn. In warmer countries, lizards usually lay eggs.
Live birth is thought to be a response to a cold climate. Both species have glossy metallic black skin with gold markings.
On the Otago skink, the gold splotches are larger and more conspicuous. Individuals of both species bask on schist outcrops on sunny days, waiting to catch passing flies, moths and other invertebrates.
They grab prey in their mouths. Crevices in the rocks provide hiding places and frost-free homes for the skinks in the winter months.
They are long-lived. In the wild they are known to live for up to 20 years and one individual in captivity in the North Island is more than 37 years old and still going strong.
But Otago skinks are also slow to mature, with breeding not starting until they are three or four years old. Like most skinks, the Otago and grand skinks are omnivores.
Their diet is thought to include a range of fruit from coprosma bushes and the porcupine shrub (Melicytus alpinus).
Lizards may well play a seed-dispersing role for the porcupine shrub, which produces its white berries on internal branches unavailable to birds.
Otago and grand skinks are known to move between rock outcrops. One marked Otago skink moved 70m in two weeks, and a grand skink was observed to move 139m.
Movement over pasture rather than through tussock grassland may make them more vulnerable to predators.
The Australasian harrier hawk and New Zealand falcon are natural predators but feral cats are probably the most dangerous introduced predator.
Magpies, ferrets, stoats and rats are also likely to prey on them. The Otago skink's plight is serious. The Department of Conservation has worked hard to give them protection in the Macraes area, their stronghold, in recent years.
Some 4500ha of Macraes habitat is protected by a trapping programme (873 traps), and within that zone are two areas of prime habitat (18ha and 19ha) with good concentrations of Otago skinks where predator-exclusion fences provide additional protection.
In one of the fenced areas, a monitored population of 60 has increased to 240 in six years, proving that with protection the species will thrive.
Orokonui Ecosanctuary, on the edge of the natural range for these large lizards, is going to play its part in conserving the species by providing a predator-free environment among schist slabs brought in from the Oceana Gold mine at Macraes and Waikouaiti farmer Andrew Noone's property.
The plan is to introduce up to 30 Otago skinks from Macraes, of varying ages, into Orokonui and hope they will breed.
But first they have to spend a month in quarantine at Wellington Zoo, which has facilities for them and where the veterinarians can monitor their condition.
During quarantine, they will be checked for ailments that could be transmitted to other lizards or tuatara at Orokonui. Then they will be flown to Dunedin and their new home.
Neville Peat, co-author of the award-winning book Wild Dunedin, chairs the trust board of Orokonui Ecosanctuary. Wild Ways appears in the Magazine Section on the first Saturday of the month.
