DOC Operations Director southern South Island Aaron Fleming says the primary purpose of this operation was to protect vulnerable kiwi chicks which have been suffering from heavy stoat predation. “Through the Save Our Iconic Kiwi programme, we’ve been monitoring kiwi chick survival at Shy Lake, in the northern peninsula, for the past three breeding seasons and every year it’s the same story. Chicks are hatching, but not making it to adulthood.
Based on that data, the future for kiwi at that site was looking increasingly grim, Aaron says.
“We know the adult population is relatively stable – an adult kiwi is a pretty solid match against a stoat. Chicks on the other hand are extremely vulnerable and if we can’t get a healthy number of them making it through to adulthood to contribute to the population, then we are faced with the reality of one day losing them here forever.”
Wet Jacket, in the heart of the Te Wahipounamu World Heritage Area has never had any type of predator control in the past. Because of this, it’s proving to be a valuable site for further research on outcomes from predator control. Additionally, it’s also providing some data to go towards DOC’s kea management and kea Code of Practice for aerial 1080 operations.
Nationally, DOC is working with Ngāi Tahu and stakeholders on how to improve and build upon years of research into a strategic approach to kea recovery that encompasses the risks and benefits to kea from 1080 predator control, to inform our Code of Practice and other risk mitigation measures.
“At Wet Jacket, we have been monitoring 21 kea since 2019 in the lead up to this operation. However, prior to the predator control operation, only six transmitters were still active. This could be due to predation – ground nesting kea are very vulnerable to stoat predation, or some transmitters may have fallen off or malfunctioned.”
Sadly, following the operation three kea were found dead. Toxicology reports confirmed the cause was 1080.
“The loss of any kea is always upsetting. At a population level, we know kea do better with 1080 predator control than without it. Following a beech mast, when we get stoat plagues, nesting success in places without 1080 predator control is only about 10%. In places with 1080 operations it’s much higher – about 70%.
“However, it doesn’t make it any easier on the team when we do lose individuals, despite the bigger picture.”
While the sample size of six tagged kea through the operation is not big enough to be representative of the population in the area – and it was never intended to do so – it will still provide valuable insights for long-term management and refining our predator control operations.
Aaron Fleming says DOC’s current focus is around threat mitigation and adaptive management for kea, but will also use these findings for further research into understanding kea behaviour too.
Ultimately, we want to protect as many birds as possible during an aerial 1080 operation, Aaron says.
“Kea conservation is extraordinarily complex.”
“You’ve got these gregarious, intelligent, curious parrots who will take off with anything that isn’t nailed down, and sometimes even nails are no match for them.
“They tamper and get caught in traps, get lead poisoning from eating nails and flashings off buildings, and play in traffic in high-visitation sites. But the number one risk for them is predation from stoats so we need to everything we can to strike that balance between protection at a population and individual level.”
DOC continues to invest significantly to improve our strategy for kea risks from human-led activities, and the results from Wet Jacket will help inform our ongoing approach.
In the meantime, rodent and stoat tracking results from the Wet Jacket operation are expected in August/September, while kiwi chick numbers will be available early next year following this year’s breeding season.
“1080 remains our best chance to protect these tokoeka chicks – along with many other vulnerable species in the area. A population turnaround won’t happen overnight, but this is a first step into securing their future in Fiordland.”
Read further background information here.