Auckland's island-hopping stoat: Inside the bid to outsmart an 'expert killer'

Saturday, 25 July 2020

Nine weeks after first being spotted, an elusive stoat is still on the run from the Department of Conservation on Auckland's Motutapu and Rangitoto islands (video first published July 25, 2020).

An island-hopping stoat continues to outsmart Auckland authorities – and the window to catch it is about to close.

Stoat footprints were spotted by a ranger on Motutapu Island in Auckland’s Hauraki Gulf on May 20, just a few weeks after a stoat was confirmed on the neighbouring Motukorea/Browns Island in mid-March.

Stoats pose a significant risk to threatened native birds and lizards – the stoat on Motutapu Island killed a kākāriki, a New Zealand parakeet, in May.

DOC’s Kata Tamaki, 26, checking one of about 350 traps spread across Rangitoto and Motutapu islands.

Kata Tamaki, 26, is the biodiversity supervisor for the Auckland Inner Islands at the Department of Conservation (DOC).

**READ MORE:

A stoat has been running amok on Rangitoto and Motutapu islands for nine weeks despite trapping efforts.

* Island-hopping stoat: Fresh tracks detected on Motutapu and Rangitoto islands

* Stoat could be island hopping in Auckland's pest-free Hauraki Gulf

Most of the traps on Rangitoto and Motutapu contain the “classic rabbit and egg bait”.

* Hunt for stoat on pest-free Hauraki Gulf islands continues as parakeet found dead

* Stoat thought to be on Auckland’s Motutapu Island threatening native birds, lizards

Kata Tamaki, 26, DOC’s biodiversity supervisor for the Auckland Inner Islands.

But her role during the stoat incursion is as operations leader on Motutapu Island.

Extra monitoring of 17 endangered tūturuatu/shore plover and takahē has been happening with a stoat on Motutapu Island.

She said the stoat is “definitely being difficult”.

“It’s been quite hard to pinpoint where it is and try and lure it into a box.”

The job of dog handler Lois Clayton and 12-year-old border terrier Gecko is to keep track of where the stoat is and where it’s been.

Tamariki said winter is the hardest time to catch stoats as they go into their dens, not usually emerging until early spring.

Dens are well hidden and can be tree trunks or rabbit holes.

The stoat has been travelling between Motutapu and Rangitoto islands near the causeway.

Across Motutapu and Rangitoto islands there is a network of about 350 traps filled with a mix of lures, which are checked weekly.

There is the “classic rabbit and egg bait”, but there is also hay from chicken barns, nesting materials from other stoats and ferrets and a cork covered in salmon (apparently the stoats love it).

Traps dot a track on Rangitoto Island heading towards Motutapu Island, marking part of the stoat’s journey between the two.

When Tamaki drives Stuff along a track in a UTV from Rangitoto Island to Motutapu Island’s causeway, a seeming pathway of traps guides our way.

But so far the stoat has not taken the bait.

The job of 12-year-old border terrier Gecko is to sniff out mustelids – stoats, weasels and ferrets.

Tamaki described this as “super frustrating”, particularly after the stoat was seen climbing up a cliff on Motutapu on Monday morning.

“The week to trap it was this one.”

Motutapu Island provides a safe haven for threatened and at-risk native wildlife including kiwi, takahē, tūturuatu/shore plover, tīeke/saddleback, kākāriki/red-crowned parakeet, korimako/bellbird, and shore skink.

It was dog handler Lois Clayton and her 12-year-old border terrier Gecko who sniffed out – and saw – the stoat on Monday on their second trip to the island since May.

The plan was for Clayton and Gecko to spend the rest of the week between Motutapu and Rangitoto, from dawn until dusk, trying to track the stoat’s movements and find its den or dens.

A ranger first spotted the stoat’s tracks on the stretch of beach near the Motutapu Outdoor Education Camp on May 20.

Clayton said they’d found evidence of prints and birds the stoat has killed, which was a good starting point.

But figuring out how far and where it is travelling, where it is hunting and killing is next.

The stoat may continue to evade capture for several months.

“Those are very good places to put traps, where it’s going to be looking for food.”

It was Clayton in May who found some of its kills – the kākāriki and brown quail.

“Fresh is best, so they’ll kill when they want to eat. If they don’t eat all of it, they’ll stash it to come back later in case they don’t find anything fresh,” she said.

“An island like this, it’s got so much beautiful native birds out there, it’s like a smorgasbord for a stoat.”

DOC strongly suspects the stoat’s first smorgasbord was on Motukorea/Browns Island in mid-March.

Miranda Bennett, Auckland Council’s southern regional parks senior ranger, said council teams had also faced the “challenge of outsmarting the stoat”.

Clayton and Gecko detected the stoat during routine checks and it was not long before scent trails were picked up, footprints were found in the sand and the carcasses of birds such as rock pigeons and sparrows were uncovered.

But Bennett said it was always a concern the stoat would get bored and go elsewhere. At 60 hectares, Motukorea has plenty of food, but more grassland than green cover compared to other islands in the Hauraki Gulf: “Stoats don’t tend to like that.”

But it was also always a hope the council and DOC would get the stoat before it moved to the likes of Motutapu and Rangitoto islands and their more vulnerable species.

“They’re expert killers – their number one priority is eating,” Bennett said.

“We ran our operation through into June but towards the end of May we were starting to get an idea it had moved on – we weren’t getting any fresh signs.”

Bennett said there is “high suspicion” the stoat on Motukorea, Motutapu and Rangitoto is one and the same, but there is a possibility it isn’t as several meat baits with toxin in them were taken on Motukorea.

“There is the possibility it consumed that and died on the island.”

Nine weeks down on Motutapu and Rangitoto islands and four months on from the first stoat incursion, will the island-hopping stoat ever be caught?

Bennett said the “crafty little beggars” can take a long time to catch if they are “trap shy”.

This situation isn’t out of the ordinary, she said.

Kāpiti Island was believed to be stoat free in 2012 after a two-year, $600,000 trapping and monitoring campaign saw three stoats caught after the first was sighted in late 2010.

“It’s not unusual for these operations to take several months. Every one is different – one trapping won’t always work,” Bennett said.

“But we use all of the tools in our tool box when we’re fighting these situations.”