Giant gecko returns to the mainland after a century
They're our biggest gecko but after being hammered by introduced pests Duvaucel's gecko haven't been seen in the wild on the New Zealand mainland for over a century.
Now eagle eyed visitors to the Tawharanui Open Sanctuary, part of Tawharanui Regional Park in north Auckland, have the chance to spot them, after 80 were successfully reintroduced behind the predator proof fence in November.
The 588 hectare Tāwharanui Open Sanctuary is predator free apart from mice and scientists led by Dr Manuela Barry from Massey University plan to monitor the impact these little beasties have on the native gecko population over a 10 year period.
Duvaucel's geckos are also found on Tiritiri Matangi Is off Whangaparaoa Peninsula after 19 were released in 2006, followed by a further 92. But Tiritiri Matangi has no mice and the Tawharanui release will help to understand what would happen if mice made it onto offshore reserve islands.
The mice are known to predate shore skinks in the sand dunes, Auckland Council Open Sanctuary Senior Ranger Matt Maitland says, although they have managed to maintain their numbers.
Growing up to 30 centimetres long, weighing 120 grams and living up to 50 years old the animals give birth to just two live young each year.
In early life they are vulnerable to predation but as they are fairly large when born Maitland is hopeful they will be big enough not to be predated by the mice. New Zealand gecko's - apart from one species - give birth to live young. Aside from some in New Caledonia all others lay eggs.
TOSSI volunteers had a chance to get up close to a couple of them on the 6 November at a public introduction before the big release. Volunteers have a big hand in the operation of the Sanctuary and the introduction of native wildlife.
"TOSSI volunteers are delighted to welcome these beautiful geckos back to a protected environment. This is a wonderful reward for years of hard work," says TOSSI Chair Alison Stanes.
"Massey University researchers and TOSSI volunteers will monitor these geckos' success in the presence of mice for the next decade. Results will inform the future release of this and similarly vulnerable species to other mainland sanctuaries," Dr Barry says.
Rather than coming from Tiritiri Matangi the gecko are from a captive population at Massey University's Albany campus, from animals that originally came from the Mercury Islands off the Coromandel.
The young gecko's were put into protective piping with sealed ends for their journey north to be released.
Removing mice remains one of the eradication plans for the park, Maitland says.
"Because they have a small home range it is possible to eradicate them in pockets. We have already started this in some areas of the park including at the gecko release site."
This is also the first stage of a reptile introduction programme at the park that will also nclude other skinks and gecko's, Mailand says.
It's another sign of confidence in the park as a part of national conservation efforts and is just one of several research projects currently underway at Tawharanui, he says.
Research often plays a part in the reintroduction of species at the park including kakariki and saddleback which were also part of research through Massey University.
The impacts of mice as predators saw a huge poison operation this year on sub-Antarctic Antipodes Island. It is hoped around 200,000 mice that had been predating native wildlife there including nesting sea birds have been eradicated.