The terrier is trained to confirm the presence or absence of possums in hard-to-access areas on the Otago Peninsula. Photo / Supplied
He’s small enough to slip under gorse, quiet enough to work through penguin colonies, and trained to detect what humans can’t see – and now he may have helped finish one of Otago’s longest battles.
His name is Scout, and he’s a 4-year-old border terrier that has become one of the most powerful tools in the push to rid the Otago Peninsula of possums – a mission that may already be over.
As a certified conservation dog, Scout is trained to detect possum scat (droppings), working alongside his handler Jonah Kitto-Verhoef through the Halo Project, one of Predator Free Dunedin’s delivery partners.
Together, they have spent months traversing steep coastal cliffs, dense bush and farmland, searching for the last traces of possum presence.
“At this point, we’re fairly confident we’ve got them all,” Kitto-Verhoef said.
“Now it becomes a game of statistics and probability when you’re at those really, really low numbers.”
Years of coordinated work by the Otago Peninsula Biodiversity Group (OPBG), Predator Free Dunedin and partner organisations have driven possum numbers to near-zero.
OPBG chair Hoani Langsbury said possum control on the peninsula began 17 years ago as a grassroots effort by local landowners and volunteers.
“This has predominantly been a community project, just under 25,000 possums have been removed,” Langsbury said.
“Funding from Predator Free 2050 allowed us to speed up elimination in the last five years, but the first 12 years were entirely community-driven.”
Kitto-Verhoef said the project had been in a “mop-up phase” for about a year, with Scout central to confirming possum absence rather than active removal.
He is certified through the Department of Conservation’s conservation dogs programme, which includes formal training, assessment and regular re-certification.
Dogs must demonstrate they are safe around non-target species (critical in areas with wildlife such as hoiho and other native birds) and that their detection work is accurate.
Unlike trail cameras or traps, which often need weeks in one location, Scout allows teams to move quickly through large areas and get near-immediate answers.
“With the dog, we can go in and really quickly work out presence or absence of the target,” Kitto-Verhoef said.
“That’s a massive game changer, especially when you’re trying to confirm eradication.”
Scout doesn’t chase animals, but locates possum scat and indicates when he finds it by lying down and wagging his tail.
His reward is a squeaky pink ball, which Kitto-Verhoef said is all the motivation he needs.
Once Scout indicates, Kitto-Verhoef then confirms the find and grades it for freshness, helping build a picture of potential home ranges and whether possums may still be active in an area.
The final stage of eradication has proven more complex than earlier modelling suggested.
Kitto-Verhoef said earlier assumptions that possum home ranges would expand as density dropped had not always held true.
“What we’re seeing is that females often stay quite tightly clustered in prime habitat and don’t move much at all,” he said.
“Males roam more, but a lone male can’t establish a population. A single female can.”
The peninsula operation includes AI-enabled traps equipped with cameras that provide near real-time information about what species are moving through an area, helping teams decide where to focus effort.
Thermal drone surveys are also used in areas that are difficult or unsafe to search on foot.
Drones detect possums while they are out feeding and mark locations, which are later followed up on by ground teams.
Some of the peninsula terrain can be challenging, with Scout often kept on a rope in steep areas to prevent accidents, Kitto-Verhoef said.
Behind Scout is a broader collaboration involving staff from the Halo Project, City Sanctuary and the Otago Peninsula Biodiversity Group working together as Predator Free Dunedin, with additional support from specialist teams.
Langsbury said the benefits were already visible, with forest birds returning and improved success for ground-nesting species.
“We’re seeing bellbirds, tūī, and even kākā recorded back across the peninsula,” he said.
Despite the serious goal, Scout himself remains an unlikely conservation hero.
“He’s a pretty small border terrier ... People are always surprised this little dog is doing such important work,” Kitto-Verhoef said.
Ben Tomsett is a multimedia journalist based in Dunedin. He joined the Herald in 2023.