Park pest battle heads for the hills
Toby Reid is hovering 40 metres above the former Hadfield farm at the back of the Awaroa estuary.
Below his Robinson 44 helicopter. a 40-metre cable is swinging in the wind. His ground crewmate, Mike Standish-White, grabs the big hook at its end and slips it under a loop of No 8 wire that is wrapped around a bundle of 12 double stoat traps.
After he gives the pilot a thumbs-up, the helicopter rises, the cable goes taut, and soon the 120-kilogram payload is sailing up a ridgeline, on its way to being placed in one of the most remote parts of Abel Tasman National Park.
The load is part of about 2000 traps that are being distributed over 15,000 hectares of the park, or 70 per cent of the park's 22,000ha.
The trapping effort is one of the most significant initiatives undertaken by Project Janszoon, the $25 million, 30-year private effort to combat pests and restore the park's native plants, birds and animals, and represents the largest stoat trapping network undertaken by a private trust in New Zealand.
Project Janszoon director Devon McLean says it is an important milestone for the trust, which was launched two years ago.
"This is a permanent commitment to lowering stoat numbers in the park over the long term. Bringing stoat numbers down significantly will make a big impact on birdlife and allow us to prepare for reintroduction of ground-nesting birds like pateke (brown teal), which are particularly vulnerable to stoat predation."
Mr Reid designed the simple hook system specifically for the loads of stoat traps. It means they can be placed at sites without needing anybody on the ground to unhook the load, saving valuable time and resources.
From Awaroa, Mr Reid flies the boxes into the bush and returns in an average of about five minutes, compared to what would be a three-hour tramp.
Although it takes a lot of skill to navigate to precise GPs coordinates and weave his way between kahikatea trees that can be higher than the cable is long, in some ways Mr Reid's part of the job is the easy one.
Four men are camping out in the bush for a week at a time to retrieve the bundles of traps and then hump them along new tracks, placing a trap every 100m along trap lines a kilometre apart.
"It's hard work. It's tiger country," says Department of Conservation ranger Jake Goonan as he demonstrates how the men will fit two of the 10kg traps on to a pack frame and carry a third in their arms as they climb through the steep gullies and ridges in the inhospitable interior of the park.
Contractors had to cut tracks into the are to service the trap lines, and the teams will set them up by March 1. They will be checked every month after that.
Mr McLean says that in the first block of new stoat traps, which were laid last summer through 5000ha of the highest reaches of the park around Canaan and Wainui, initial counts of stoats were high, but they quickly dropped to about 10 per trap line.
"We know we've got a lot of pressure on the stoat population, which is what we need."
Pest numbers could explode in the park later this year as conditions look set for a beech seed "mast". Mr McLean says Project Janszoon and DOC are monitoring the seed drop and the rat population and, if necessary, will supplement the trapping operation by using 1080 as a "knockdown tool".
He says the project began in the higher parts of the park because that is where the most diverse bird life is.
About 1500ha on the coast of the park near Torrent Bay and Bark Bay will be laid with traps at 10 times the density of the current project, in an effort to bring more birds to where most of the visitors to the park are.
Mr McLean declines to give a cost for the trapping operation but says the plan has always been to "front-load" the spending of the $25m, because Project Janszoon's success depends on installing infrastructure such as the tracks for trap lines.
"It's great to see it coming together. There's still plenty to do but it's good to get some of these big jobs carved out."
The Nelson Mail