Nineteen of New Zealand's most highly trained noses have spent the past week sniffing out invaders in the Bay of Islands.
The elite team of pest detection dogs — ranging from a ridiculously cute jack russell to a one-eyed heading dog and a floppy-eared springer spaniel — have been staying at a Russell holiday park and going on daily missions to wharves, pest-free islands and bush reserves.
Each pooch is trained to detect one type of pest. There are rodent dogs, mustelid dogs, feral cat dogs, even a skink dog and an Argentine ant dog.
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Since Monday their noses have been twitching furiously as they scour the islands of the Ipipiri group between Russell and Cape Brett, where an ambitious wildlife restoration plan called Project Island Song is underway.
Introduced pests, especially rats and mice, were eradicated in 2009 but the price of the islands' popularity and proximity to the mainland is eternal vigilance.
Today the crack canines and their 18 handlers will wrap up their work and head back to their homes as far away as Stewart Island and even the Chathams.
Fin Buchanan, a senior advisor for DOC's Conservation Dog Programme, said the purpose of the annual get-together was two-fold.
''It's an opportunity for all our dog handlers to do a job together because they're scattered right through the country, from Stewart Island to Paihia, and learn from each other. We've got some very new handlers here and some who've been doing it for a long time,'' he said.
The other purpose was to give the host area — this year the Bay of Islands, last year the Mercury Islands off Coromandel — a thorough pest surveillance operation.
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Between forays to the islands the dogs had carried out mainland work and biosecurity checks at every wharf and marina around the Bay of Islands, guarding against the threat of rodents stowing away in boats or luggage.
Yesterday they searched the Bay's many lesser islands and rock stacks as well as the area around Marsden Cross on the Purerua Peninsula.
As of last night no pests had been detected on the islands, a result Buchanan described as ''very reassuring''.
''Urupukapuka Island has suffered a number of rat incursions this year, but they've obviously got on top of that.''
On the mainland the picture was not quite as rosy, however. Feral cat detector dogs found 30 cat scats — that's a polite world for poo — deep in Opua State Forest, in an area where conservation group Bay Bush Action is about to expand its pest trapping operations, while mustelid dogs caught a whiff of stoat or weasel on the shoreline at Waitangi Golf Club, a stone's throw from the Treaty Grounds.
Buchanan said the dogs were always muzzled when threatened wildlife was present. Their job was not to kill pests but to raise the alarm if they were detected.
Then it was up to local DOC staff or contractors to lay traps or, in the worst case, poison baits.
Before the annual get-togethers started pest checks targeted a single species with one dog and handler sweeping an island at a time.
"In those days, a rodent dog could have told us there's no rats on the island but left a stoat undetected and feasting on native birds for maybe months until a mustelid detection dog made its visit."
That changed three years ago when Kiwibank came on board as sponsor of the Conservation Dog Programme. The bank has just signed up for another three years.
The extra funding had ''raised the game'' with the programme now boasting a full-time manager, two senior advisors and four full-time handler teams within DOC, an in-schools education programme and the ability to bring people and dogs together for on-the-job learning.
Five years ago, the dog handlers were a passionate but loose-knit group, offering conservation services where and when we could, Buchanan said.
Now the programme had 91 four-legged staff and 74 human handlers. Some worked directly for DOC while others were private contractors or employed by local authorities.
Some dogs, like those in the Bay of Islands this week, were trained to detect pests while others located threatened species such as kiwi and kakapō.
Kiwibank chief marketing officer Simon Hofmann said the government had only just announced its Predator Free 2050 target when the bank partnered with DOC in 2016.
''Since then, we've seen the Conservation Dog Programme go from strength to strength. Exercises like this are critical, as they allow our threatened species the chance to thrive.''
If New Zealand is to have any chance to become predator-free by 2050, every one of those 91 highly-trained noses — and more — will be needed.
New Zealand's pest detection dogs are trained to sniff out a wide range of alien invaders threatening our unique native wildlife.
Rats will eat anything: Birds, snails, lizards, weta, eggs, chicks and larvae. They also munch on fruit and seeds that would otherwise be food for native wildlife.
Mustelids are carnivorous killing machines, hunting anywhere and anytime. Stoats are the single biggest threat to kiwi chicks.
Feral cats can range over large distances — up to 6km in a night — eating birds and bird eggs, rats, bats, lizards, mice, weta and other insects.
These highly aggressive ants form huge super-colonies, pushing out other ant species and eating anything they can get their mandibles onto — even birds.
These fast-breeding Australian invaders, also called rainbow skinks, outcompete native skinks and lizards in the fight for food and habitat.
While most detection dogs are trained to find animal pests, a few can sniff out pest plants such as spartina. This invasive grass takes over estuaries, robbing native fish and plants of habitat.