Archives For 30/11/1999

By Paul Jacques

2011-12 has been another successful season of rat trapping in Mason Bay, Stewart Island/Rakiura. Rat capture dropped steadily from 165 in August down to just 8 in December, providing a welcome break from rat predation for breeding birds such as red-crowned kakariki (pictured), bellbird, brown creeper and Stewart Island robin. By the end of the season the rat tracking rate was 0% within the trapped area compared to 30% in un-trapped forest nearby, good evidence that the 331 kills this season have again reduced the rat population significantly.

Red-crowned kakariki

NZDA trappers re-baiting a trap at Mason Bay

Between August and December each year five teams of keen NZDA volunteers head to the Bay to check, re-bait and maintain the network of over 300 traps. DOC helps out with travel costs and also provides technical assistance such as running tracking tunnels to measure rat abundance at the start and end of each season.The Mason Bay rat trap network is a co-operative project between the Southland Branch of the New Zealand Deerstalkers Association and DOC Stewart Island Field Centre. The traps are run during the bird breeding season with the aim of increasing the productivity of native birds by reducing rat numbers at this crucial time of the year.

The traps protect about 200 ha of coastal podocarp/broadleaf forest situated between the nationally important Mason Bay sand dunes and the freshwater swamp. While controlling rats in this spectacular environment the volunteers have the opportunity to hunt both red and white-tailed deer and also have an excellent chance of spotting a kiwi.

Looking South across the trapped area from the Big Sand Pass

This season’s trapping will begin again in August. This year we plan to trial a bird monitoring method used by other community groups around New Zealand, to measure changes in bird numbers over time in response to trapping. We will also be looking into options for feral cat control to run alongside the rat network.

For more information about the project please contact the Southland NZDA or DOC Stewart Island Field Centre.

Are we sitting comfortably? Good, then I’ll begin,

Today we’ve added some interesting videos to our website about our use of 1080 poison. The following is a bit of a background about why we undertake pest control, and how we do it. At the end of this post, you can find links to the new section, and all sorts of information about pest control.

Background

New Zealand has been here for around 80 million years, and as far as biodiversity goes, has been largely dominated by birds, reptiles, and invertebrates. Certainly there were no humans, and no terrestrial mammals (save a few small species of bat). The upshot of this is that we have some lovely avian species that occur nowhere else on the planet. The downside though, is that they evolved to believe that they’re ten feet tall and bulletproof. Many of our native birds (like kakapo or kiwi) make their nests on the ground, and have lost their ability or indeed need to fly.

Noted international conservationist David Bellamy once described New Zealand as ‘The land without teeth’, and the land without teeth we were. That is until we welcomed certain toothed creatures with open arms, into our toothless grin of a paradise.

Public enemy number one: Possums don’t just decimate our vegetation, they also regularly predate upon our birds’ chicks and eggs.

That’s when the trouble started

If you’re from around here, hopefully you’ll already know how these four-legged furries have completely run amok on our native wildlife and their habitats. Possums decimate forests on a nightly basis; rats and stoats raid nests full of eggs and chicks; and we even have unlikely enemies in such cuties as the hedgehog, who scarcely think twice about scoffing ground-nesting birds’ eggs or lizards while on their nocturnal missions.

To me it’s a no-brainer. We either have our unique dawn chorus (once described by Capt Cook as ‘deafening’), or we don’t. And when I say unique, I really do mean unique. There is nothing like our dawn chorus to be found anywhere else on this planet, and to me and the people I work with, that’s something special.

Our native species are national icons: From the kiwi emblazoned onto international rugby league jerseys, to our national Spokesbird who is surely the first parrot to represent a nation. Without these, what sort of icons are we left with?

National icon: Without protection 9 out of 10 kiwi chicks raised in the wild will perish. Photo: Ian Gill

Pest control

We use a bunch of different techniques to control pests here in Aotearoa. Last year for instance, we worked with the private firm Good Nature to develop and implement a self-setting trap to control stoats and possums. Relatively speaking, this innovation is highly cost effective, and we’re now working on one for possums too.

The self-setting trap in action. Photo: Dave Hansford.

Ground control – trapping, culling and using bait stations – is our most widely used method of pest control, but it just isn’t viable for some of our near-inaccessible terrain.

In these cases we use aerial drops of 1080 poison. It is indeed a poison, and it’s quite effective at killing mammals. This puts us in a relatively good place to use it, since we have no native mammals (save our species of bats). It’s quite a different story for us than in other countries, where there are native mammals running around all over the show.

The use of 1080 in New Zealand has been controversial to say the least, largely because as well as being extremely efficient at killing possums, rats and stoats – which devastate our wildlife and forests – it can also kill animals like deer and pigs, which are higly valued by the hunting community. Sadly, this controversy has resulted in misinformation and untruths about our use of the stuff. Sometimes a lot of the facts are missed, either through misleading statements by opponents to 1080 or simply because it’s difficult to understand the chemical nature of how this biodegradeable poison really works (it dilutes and breaks down in water, and the active ingredient in 1080 is found naturally in plants, including tea and puha).

Non-control area in the Karangarua Valley, rata forest decimated by possums. Photo courtesy Andris Apse.

1080 Control area near Fox glacier showing rata forest in bloom. Photo courtesy Andris Apse.

Our videos

That’s why it’s great to be able to provide you with some short videos produced by one of our many passionate staff members, which will hopefully answer some of the questions you may have about 1080.

The videos are made by ‘Trakabat’ (Ian Gill from our West Coast Conservancy office). Ian has a technical background in electronics, and is pretty handy with a camera. Ian reckoned that all the technical expertise and knowledge there is around the subject was being drowned out by ‘all the noise’, so he put together these videos.

The videos have been on his Youtube page for a while now, but we thought they spoke so much sense that we’d embed them on our website too, and tell you all about them. See the first link in the list below for the videos.

We’re the Department of Conservation, and our business is conservation. If we thought that the pest control techniques we currently employ were having a significant negative impact on what we’re trying to protect, then we would stop using them. What other agenda could we possibly have?

Thanks for reading. To read and see more about 1080, check out the following links: