Hedgehogs wiped out from coastal area with sniffer dog

Hedgehogs have been wiped out on a chunk of Canterbury's coast, thanks to a community conservation project and a dog with a great nose.

Hedgehogs have been removed from a 45 hectare containment zone on Kaitōrete Spit by Pest Free Banks Peninsula, a community-led group made up of councils, agencies and iwi.

The impressive milestone was thought to be the first time this had happened on mainland New Zealand without a pest fence.

Kaitōrete - a sliver of land between Te Waihora Lake Ellesmere and the Pacific Ocean - is a windswept home to a range of resilient native plants and animals.

But Tim Sjoberg from Pest Free Banks Peninsula (PFBP) said hedgehogs pose a big threat.

"Everyone puts the old milk and bread out for hedgehogs, I certainly did as a youngster."

"But the more that we know about hedgehogs, the more we find out the devastating impacts they have, not just on invertebrates, but eggs, chicks and adult manu (birds)," he said.

"[They] consume seed and seedlings, changing the structure of ecosystems."

Other species were also being targeted, including weasels, stoats, ferrets, possums and feral cats.

So what is the group's answer?

"We are using a lot of traps to tell us if there are animals there. But we're also layering that with infrared cameras," Sjoberg said.

"And of course, we have Karin and Nightshade walking through these areas, actively looking to see if the static devices, like traps and cameras, haven't been picking up the last of the animals."

Nightshade, a three-and-a-half-year-old border terrier, sniffed out hedgehogs with handler Karin Bos.

She said Nightshade went through two years of training to hone her nose to their scent - and apparently appearance.

"I would definitely begin the day with a bit of play. So I'll throw a ball around or a pinecone," Bos said.

"She really likes pinecones, I wonder whether that is because they look so much like hedgehogs!"

Play time was followed by breakfast and a toilet stop before they set off on the hunt, with a backpack full of treats and water.

Bos also fitted Nightshade with a tracking device called a Garmin collar.

"We go to the area where we want to look, we get her Garmin collar on, and if it's not too hot, she might wear a little jacket as well," she said.

"And then I basically just tell her to go find the hog, and then off she goes!"

Bos tracked Nightshade's trail, using the collar.

And it was pretty hard to miss a find.

"She gets excited and then she will start to dig a little bit at the ground. Then I tell her to wait... and I find the hedgehog."

"She gets a very good reward after, we make a big fuss of her, she gets lots of treats and pats and I usually have to give her a drink because it's all very exciting," Bos said.

Nightshade and Bos would soon be joined by a second dog team.

Terry, a Welsh Springer Spaniel, had just arrived.

His pest of choice was feral cats.

Canterbury Regional Council biodiversity leader Shaun Burkett said while it was important to celebrate the project's success clearing 45 hectares, there was still a lot of work ahead.

"The whole [of] Kaitōrete, I think we're looking at quite a few thousand hectares," he said.

"And of course Banks Peninsula itself, I think the area is somewhere in the 100,000 hectare range. So, given this success, we would look at how we can replicate it across the whole peninsula."

The programme's goal was to make the peninsula pest-free by 2050.