Photo: SUPPLIED / DEPARTMENT OF CONSERVATION / SONJA MURRAY
Photo: SUPPLIED / DEPARTMENT OF CONSERVATION
- Critically endangered Alborn skink has declined to 30 from "50-60 in 2023"
- The Department of Conservation says a mouse plague has caused havoc for the rare species
- A pest control operation on the West Coast's Victoria Forest Park will seek to control the burgeoning mice numbers by placing a toxin in bait stations
- Surrounding areas will be restricted to hunters for three years due to the risk of pig and deer consuming the toxin
A critically endangered lizard on the West Coast is facing extinction because of a "mouse eruption", the Department of Conservation (DOC) says.
The number of Alborn skink has halved in less than two years with only 30 lizards remaining.
The lizard was discovered in the 1990s and has been rarely detected since.
Increased mice numbers have been pinpointed as the reason, forcing the department to take "emergency interim measures" to save the dwindling lizard species.
DOC senior science advisor James Reardon said for such a rare species to decline at this rate, the situation was "an emergency" for the department.
"We've been monitoring mice in this area for quite a few years now," he said.
"This is the highest number we've seen in five years."
Mice were small enough to enter the small holes and burrows where the skinks live and eat them alive.
A pest control operation is set to be carried out on a 10-hectare section of Victoria Forest Park near Reefton, where toxin brodifacoum will be placed in bait stations.
Typically, the department prefers other schemes, including relocating animals to "pest-free offshore islands" or mammal proof fencing.
Reardon said it was a short-term solution until a predator proof fence can be built later this year.
"There is one in the pipeline for Alborn skink," he said.
"There's just a bit of a process of securing resources and lining up engineers and contractors.
"Of course, nature doesn't wait for our plans and we have a mouse eruption right now and that's why we have to respond immediately."
As brodifacoum "persists" in the environment, surrounding areas of the operation will be off limits to hunters for three years.
This is due to the risk of game animals consuming sub-lethal amounts of the toxin, including the poisoned mice, that could enter the food chain.
The "caution zone" includes a 5 kilometre radius zone for pigs, and 2km radius for deer.
Both DOC and the New Zealand Nature Fund were attempting to raise more than $1.5 million as part of efforts to save the lizard.
The sum included more than $940,000 for 855 metres of predator proof fencing.
"We're still learning about the ecological interactions of our threatened lizards and pest dynamics," Reardon said.
"Everything we learn points to them being more and more sensitive and we're losing these populations faster and faster.
"We really are in dire straits."
More than 90 percent of the country's 126 endemic lizard species are considered "threatened".
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