Before Operation Nest Egg, rowi chicks made a tasty morsel for stoats. Photo:
A long-standing rescue mission for the country's rarest kiwi species is being rewarded.
The rowi population in South Westland dropped to an estimated 160 birds in the 1990s, but considerable mahi has brought them back from the brink.
Without intervention, only five percent of rowi chicks would survive to their first birthday, due to eggs not hatching, predators killing them or natural causes.
A short boat ride across Lake Mapourika is the the rowi kiwi sanctuary in the South Ōkārito Forest.
Department of Conservation South Westland operations manager Wayne Costello said rowi chicks were walking morsels for stoats.
"Just about every kiwi that was hatched in this forest back when there was no protection would have been killed," he said. "The only way you could get around that is by taking the eggs and raising the chicks to 1200 grams off-site, and bringing them back."
Operation Nest Egg - a nationwide kiwi recovery programme - boosted the survival rate to about 50 rowi per season and has since wrapped up in Ōkārito.
By 2015, the population was about 450 rowi.
DOC South Westland operations manager Wayne Costello Photo: RNZ/Tess Brunton
The rowi have also benefited from a Predator Free South Westland mission that has nearly eliminated stoats, possums and rats from more than 100,000 hectares.
Costello said it was promising progress.
"Rowi were a species that were on the brink of extinction and we brought them back from that, using Operation Nest Egg over a period of time, but I guess the goal for ourselves and our partners, Kāti Māhaki, has always been about seeing them survive in place, in situ, and providing the environment for them to be able to do that."
West Coast Wildlife Centre has a purpose-built hatching and incubation facility.
"There was a huge conservation need," director Richard Benton said. "Gosh, over the last 15 years, we've hatched and incubated over 353 rowi eggs."
The work has paid off - the population is now about 700, eggs have been left in the wild in recent years, rowi are spreading further out and some are being moved to new areas.
DOC team lead supervisor Anya Kruszewski was gearing up to search for a juvenile rowi in North Ōkārito that was ready for a new home.
Transmitters were attached to rowi soon after they hatched to monitor them and for regular health checks.
"It's been great to see higher survival and that we can leave the eggs to hatch naturally," she said. "It also gives us the chance to handpick the genetics that we want to go to the Omoeroa ranges, but it's also more natural for the kiwi."
DOC team lead supervisor ranger Anya Kruszewski searches for a juvenile rowi in North Ōkārito. Photo: RNZ/Tess Brunton
Kruszewski used a transceiver to pick up the juvenile's transmitter frequency and an aerial to work out where it was. She began walking along the dirt track next to the bush, trying to hone into its location.
After enough promising beeps, we headed into the bush, pushing past ferns and mossy trees. They had to prepare for all types of terrain as they sought out rowi, she said.
"It could be swampy, it could be mānuka forest. It could be really large rimu trees with a bit of an undercanopy.
"It could be a bit steeper, there would be some slips that you have to walk across, some gullies, also creeks and rivers we have to cross. It's pretty much anything."
She found the rowi juvenile deep within a long, moss-covered, hollow log and then the problem-solving began, as she tried to work out how to reach it. That involved blocking exits and using the transmitter to work out exactly where in the log it was.
After a while, the transmitter showed it had managed to silently escape. The ground got swampier the further we trekked into the bush, following the beeps from her transceiver.
Eventually, the beeps led to a moss-covered mound. Kruszewski blocked the exits, before reaching in and pulling out a rowi.
West Coast Wildlife Centre director Richard Benton said rowi needed a helping hand when he opened doors. Photo: RNZ/Tess Brunton
"This is the juvenile we're looking for," she said. "You can see here it's got a transmitter on.
"What we'll do before we translocate, we'll just check weight, check it's all healthy and it's good to move, but really pleased."
The juvenile passed the health check with flying colours, before it was taken to Franz Josef, joining others flown into the Omoeroa Ranges, where they were released into a suitable burrow area, and headed off to explore their new home.
DOC would continue in situ monitoring for the next couple of years, keeping an eye on their survival rates, alongside the predator free work.
"We might look into moving them to newer areas, where they're already existing or we expect them to move naturally, but with our plans, we do want to increase numbers. We want to get to at least 900 by 2030."
Okarito Kayaks co-director Barry Hughes said partner Gemma used to work as part of Operation Nest Egg.
"I've been fortunate enough to spend time in the bush here and had kiwi run through my legs, trying to capture them to try to provide the support that they need through Operation Nest Egg," he said. "It's a key part of the stories that we tell to our visitors.
"These projects and the ingenuity behind them are absolutely incredible. For me, Operation Nest Egg makes a great story to educate people about the lengths and the work that we go through, as a country, to support nature."
He welcomed the predator-free work in the region, saying it dealt with the problem, not just the symptoms, and looked at entire forest health.
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