Kiwi calls fill night air at Whinray reserve

Thrilled at species recovery: Ecoworks’ Steve Sawyer has been working in conservation at Whinray Reserve. File picture by Liam Clayton

The Whinray Scenic Reserve at Motu is home to native brown kiwi which have been returned from the brink thanks to conservation efforts over the past 30 years, but the area is also home to other native creatures who are also benefiting from conservation work. Ecowork’s Steve Sawyer explains . . .

The Tairāwhiti brown kiwi population is making a return after almost a quarter of a century of conservation effort.

During the late 1990s only eight kiwi could be found within the stunning Whinray Scenic Reserve. Low numbers of kiwi were scattered across the Motu area; however, most were being killed by ferrets and stoats. Since the late 1990s and after 24 years of pest control, kiwi can again be heard calling at night at Motu, where the Whinray Eco Trust, the Motu community and Ecoworks NZ manage the pest control and wildlife recovery within Whinray Reserve.

“Our Raukūmara-Tairāwhiti kiwi were on the brink of extinction and now the Motu area holds over 100 kiwi,” Ecoworks’  Steve Sawyer said.

Mr Sawyer has coordinated the pest control and fundraising for the last 24 years to make this possible and has received strong support for this from the Department of Conservation, the Williams family trusts, Save the Kiwi and many other groups.

“Over 40 small kiwi chicks have been successfully raised within the Motu kiwi kōhanga — a predator-proof fenced enclosure full of worms, weta, beetles and other insects perfect for growing healthy kiwi chicks. After just three months our kiwi chicks weigh one kilogram and are ready to go back into the forest where they originated.  A small radio transmitter is attached to their leg and they are released.

“Over 1000 hectares of Motu forest, QEII covenant, farmland and roadside is trapped for stoats and other pests which ensures both the adult and young kiwi are safe. Over 1000 traps are operational within the treatment area and this has recently grown to almost 2000 hectares with support from John and Lucy Larsen and their Pakihi property.

“We have recently located six more adult kiwi pairs living on Pakihi and these birds are now protected with pest trapping. Dan and Jane Griffin and the Fisher family also provide habitat and invaluable support for the project in the area. Without great landowner support this would not have been possible.

“The kiwi are the iconic flagship species for this project and this has enabled us to raise funding for pest control. However, many other less known but just as important species have benefited.  We have also discovered new species which were not previously recorded within Tairāwhiti, small cryptic and well-hidden species whose populations have recovered due to 24 years of pest control. This includes species such as the tree climbing striped skink. Skinks do not normally climb trees and this species was previously not recorded within Tairāwhiti.”

Three separate populations of the 400-million-year-old Hochstetter’s frog have been discovered within Whinray Reserve and have benefited from the intensive control of ship rats.

Long-tailed bats are in healthy abundance and are considered as critically rare by the Department of Conservation. Bats depart from large hollow trees 30 minutes after dusk each night at Motu and feed on small moths and the insects such as mayflies which hatch from clean freshwater streams and rivers.

“This rare bat is being severely affected by the slash damage to our stream beds and is likely to be lost in many areas due to predators, forest loss and stream bed vandalism.

“The North Island bush robin was once found right across the Tairāwhiti region but has lost over 80 percent of its habitat. It is doing well at Whinray Reserve thanks to intensive rat, cat, possum, and stoat control.

“The robins spend a lot of time feeding on grubs on the ground which makes them vulnerable to feral cats. Possums and rats eat the eggs and kill chicks in the nest.

“Unfortunately, the bush robin is regionally extinct across most of Tairāwhiti now and the Whinray population probably has limited genetic variety and could be easily lost as well.

“The robin is an iconic forest bird with a stunning morning song.

“Rifleman, whitehead, tomtit, kererū, korimako and weka are also doing well within Whinray and join the dawn chorus over summer.

“Other rare species are found at Whinray now. Particularly at night we have an abundance of velvet worms — a 500-million-year-old species which shoot jets of sticky glue at its prey before it consumes it.

“We have an abundance of cave weta, tree weta and ground weta which would normally be eaten by the introduced ship rat. We have also recently identified native snails of which there are over 500 endemic species within New Zealand. For us this is very exciting as it means our massive pest control effort is working.

“Technology is helping us with our pest control.

“The new auto traps built in Whakatāne are removing possums and rats and have an in-built wifi connection so we can download the catch data onto our phones. It is then stored on Trap.NZ , a national pest database app which allows us to report and analyse trap catch data, produce heat maps for high pest catch zones and compare bait preferences and analyse our trapping effort. It is also great for funding organisations as they can log in and see that traps are being maintained and how many pests are being removed within their project.

“We are also using the goodnature A24 gas powered trap alongside bird safe poison baits to control the climbing ship rats which do incredible damage. Each hectare of podocarp forest at Motu can sustain 20 rats. This means the Whinray area could hold 12,000 rats. They eat all birds’ eggs, tawa, miro and rimu fruit, forest flowers, native frogs, native bats, weta and the insects which are so valuable for ecosystem function.

“We are beginning to use AI technology with cameras which identify the pest species present and send photos to your smart phone. This is a huge benefit for sites such as predator-free enclosures where no pest is welcome, even mice.

“We also use camera traps to measure deer populations, digital spectral recorders to monitor long-tailed bats and kiwi, and thermal equipment to control pests such as possum and deer. We will soon be monitoring the forest canopy using thermal drone cameras.”

Mr Sawyer says the key to this project at Motu is good pest control to protect a high- value forest habitat from the small forest seedlings to the top of the rimu canopy.

“Intact, high-quality forest environments within Tairāwhiti are extremely rare, particularly those with strong populations of native species,” he said.

“Tairāwhiti has only 18 percent of its original forests remaining and most of these are full of pests.

“It is vital that we protect these remnant forests. These sites are acting as the ‘lungs of the planet’. They help us humans survive by literally sucking in and storing carbon and producing the oxygen that we all need to survive — us and the birds.

“Recent research and common sense indicate that huge volumes of carbon are being stored within our old-age temperate native forests such as Whinray which contain huge 1000-year-old matai and kahikatea trees as well as beneath the ground within the millions of kilometres of fungal mycelium networks both storing carbon and distributing nutrients throughout the forests — the building blocks of these incredible forest ecosystems found only within Aotearoa.

“At Whinray we have shown that we can successfully protect these incredibly valuable and rare forest sites, these ‘lungs of our planet’. Protection of these sites allows native forest to sequester carbon and at the same time protect multiple native and often rare taonga species.

“We need to achieve this on a much larger scale, however, for a multitude of reasons, particularly for ourselves, our kiwi and those species yet to be discovered.”