Shaela Smith with the first wētā from the weekend's search. Photo supplied
Hours spent scratching around in gorse were rewarded on the weekend with the capture of 10 Māhoenui giant wētā for the captive breeding programme at the Ōtorohanga Kiwi House and Native Bird Park.
The first one was discovered by volunteer Shaela Smith, kiwi house manager Jo Russell said.
“Isn’t the look on her face amazing. It took hours of searching around in gorse to find just the right wētā. She was absolutely terrified of it, but by the end of the day, she was a wētā professional. She was really awesome.”
Department of Conservation staff, Mōkau ki Runga representatives, volunteers, and staff from the kiwi house found and safely translocated 10 Māhoenui giant wētā from the Māhoenui Giant Wētā Scientific Reserve to the Ōtorohanga kiwi house.
The scientific reserve is a gorse-covered hillside.
Wētā experts said the Mahoenui wētā chose the gorse habitat because it protected them from predators, but the gorse was now being pushed aside by regenerating native bush.
In February, DOC revised the wētā’s status to nationally critical – one step from extinction – because of its declining population at the reserve.
Additional genetic material for the two-year-old captive breeding programme was required because wētā live about two years, and the programme pioneers have died off, Jo said.
It leaves the kiwi house with eggs in the ground, but they won’t know they are viable until they hatch, perhaps in spring.
“The eggs, we believe, are fertile, so that’s great considering we didn’t know a lot about this wētā at all when we first started.
“It’s pretty exciting to get to that point. The eggs themselves take anywhere from 10 months to two years to hatch. So, we are not wasting any time,” she said.
With the support of Mōkau ki Runga, the hapū that is kaitiaki, the kiwi house has brought five females and five males into the programme as a second group.
They have been selected from as distant a part of the reserve as possible, in hopes of obtaining the best genetics
“We are not doing it on our own, we’ve had tremendous support from the DOC technical advisory group,” Jo said.
“Those are the real wētā experts and we have had incredible support from Butterfly Creek, who instigated the captive breeding programme for Wētāpunga, and Auckland Zoo, who are also working on wētāpunga.”
Wētāpunga were once found on the mainland throughout Auckland and Northland. Due to habitat loss and predation, they became restricted to Little Barrier Island, where Butterfly Creek established the Wētāpunga Captive Rear and Release Programme in 2009.
“This [Māhoenui] is quite a different species. It is still a giant wētā but it has got its own behaviour. It’s subsisting in gorse rather than its natural pre-human habitat. So, there are some challenges. They are really fussy on what soil they like to lay their eggs in,” Jo said. “That took us a wee while to work out.”
It took a while to realise a dirty ovipositer did not mean eggs were being laid. The wētā was testing the soil for egg-laying suitability.
“We know they don’t like the same style of soil that wētāpunga like. They like good old-fashioned soil from the top of the Waitomo catchment. We haven’t used soil from the reserve itself because we don’t want to accidentally bring in any eggs from the reserve,” Jo said.
The soil had to be wet but not too wet. PH was not as much a factor as structure.
“She’s really sensible because she’s looking for a position to lay that won’t get waterlogged in winter, and will stay damp enough in summer. So, she’s looking for quite a specific soil structure. And we saw that at the reserve.
“We found more wētā along the ridge line where it gets a little bit drier in the middle of winter than in summer.
“It’s been an interesting two years finding out about them and working towards being able to get this animal to breed and lay eggs.
“Our next test is to get those eggs to hatch, and to raise the young nymphs through their nine nymph stages until they become adults.
“We are hoping as much as we can that we have got it right. We had lots of experts check and double check. It’s such an unknown game.”
With Māhoenui giant wētā nearing extinction, Jo said the kiwi house was grateful to the Ōtorohanga District Council and the Infrastructure Reference Group for providing funding to enable construction of the bespoke wētā breeding facility.
DOC’s work at the reserve was keeping it predator free.
At the weekend they found two dead wētā that had died of old age, and not been eaten by predators.
“DOC is doing some amazing work out there controlling the pests,” she said.
Mōkau ki Runga had also been fundamental in protecting the species.
“Their representative was with us over the weekend and they have come with us to Auckland Zoo. They have been incredible caretakers for that species.”
