Rat Attack Workshop by Fenella Christian

Environmental News Issue 12

On the Sunday of Labour Weekend the Great Barrier Island Charitable Trust held a “Rat Attack” workshop for the Great Barrier Island community. There was a turnout of 25 people all interested in learning about the best ways to catch rats, and the reasons why it is important for us to try and catch them. I went as someone who thought she knew plenty about rats, especially considering the number of workshops I have attended over the last few years in my role as secretary for the Great Barrier Island Charitable Trust. I was very surprised to discover there was still more for me to learn.

After a welcome speech and short overview of the work of the GBI Trust John Ogden handed over to Jude Gilbert from Windy Hill/Rosalie Bay Catchment Trust who started the day with a talk entitled “Humans create rat heaven – what attracts rats to your property and where is best to manage them.” The slide of a rat trap in the top of the compost bin under the lid was pretty impressive. All the places rats like were talked about and we can be assured of finding rats anywhere — rock walls being the first thing to come to my mind. At lunch time Jude also demonstrated a range of rat traps and bait stations that are available to the public to use.

Jo Ritchie spoke on “Its hell in the Bush” — bush rats — what damage do they do? Of all the predators in the bush (cats, dogs, stoats, possums, ferrets) rats have by far the biggest single impact on plant and animal life. There is the obvious damage i.e. gnawing through pipes and cables, getting into pantries, eating chook food, clothes, putty, soap etc... but Jo told us of the damage done to the bush. Rats have a huge impact on the bush, feeding on all the seeds and fruits of trees to the detriment of our native bush. They decimate the small animals and the insects. She spoke of the distances they swim and that there is no place a Ship rat can’t get to. Thank goodness we don’t have Norwegian rats here. She said that some rats live only in the trees, and I recalled seeing rats running across the top of the Kanuka one day at dusk at our place.

After a lovely lunch provided by the local Department of Conservation office we heard Matt Maitland speak on the moral and ethical issues around the killing of cats and rats. Did you know that they have to die within 3 mins otherwise it is deemed cruel and is against the law. Traps and Baits are therefore required to kill rats quickly. I might add here that Matt showed a rather disturbing video of mice cannibalizing an Albatross in some islands near Antarctica. Mice can become a problem when rats are removed and there is plenty of research going on at the moment to find ways to deal with mice.

Jude spoke about the Pest project at Windy Hill Rosalie Bay area. This project started by Jude trapping only around her house. Now the area covered by this project is approx 450 hr and it takes in a number of properties in the Windy Hill Rosalie Bay Area. Originally they started using traps only because there were issues for them around the use of poisons. However because they were unable to get the numbers below a certain percentage they decided to pulse with baits. The results were phenomenal with some areas showing no rats after a bait pulse. Four workers walk the perimeter twice a week and there are 3000+ traps and a huge area of trapping lines to manage. In the summer they close up the cat traps as a way to control the rabbits and there has been a noticeable difference in rabbit numbers when this is done.

As well as the managed area they have a control area where there is no trapping or baiting happening. They have found that there is a big difference between the unmanaged and the managed area with regards to some of the species. In a survey of the unmanaged area they only found one weta, whereas in the managed area they have weta motels that have good numbers there most of the time.

My mind boggled when I considered trying to use the same methods for the whole of Great Barrier Island and it became clear that we need to find other ways to manage rats if we are to do it at all. There has to be other ways to do it and we could probably lead the world if we can find the way.

There was great feedback from the participants in the open discussion part of the programme. In the discussion at the end of the day someone suggested that we might be able to do a bait drop in the bush areas and perhaps look at putting poisons in bait stations or use traps around dwellings or water Catchment areas.

A concern that someone mentioned is the amounts of baits we are all constantly putting into the soil while we try and reduce the rat numbers, and that the poisons we buy are toxic and accumulative. I wonder what quantities the local hardware store is selling through a year?
There was a clear message that a rat eradication has never been done on an inhabited island the size of Great Barrier Island and that as a community we need to be innovative and lateral in our thinking to find a way. What a challenge!

Kevin Parsons from the Windy Hill team took a number of people around the traps that he had set up at Mulberry Grove School the week before so they could see the types of places to put traps to be more effective.

Each participant was given a fantastic pack with an enclosed, lockable bait station, a rat trap, cover and spike to hold it in place and information about rats and rat eradication around the home.

A big thank you to all the people who attended and thank you to Windy Hill Rosalie Bay Catchment Trust, Department of Conservation, Mulberry Grove School, Auckland Regional Council, Jo Ritchie, Matt Maitland, Jude Gilbert, Stonewall Store and anyone else I might have forgotten. The Trust has decided they will repeat the workshop in other areas if people are interested.