Ducks Unlimited

Displaying items by tag: Pest Control

Monday, 19 March 2018 06:59

Wicked wasps

Wasps are one of the most damaging invertebrate pests in New Zealand; they harm our native birds and insects and compete for food with our native species. If you put together all the wasps in honeydew beech forests they would weigh more than the weight of birds, rodents and stoats combined. 
This new study has found that wasps also have a major financial impact on primary industries and the health sector. This includes: 
  • More than $60 million a year in costs to pastoral farming from wasps disrupting bee pollination activities, reducing the amount of clover in pastures and increasing fertiliser costs.
  • Almost $9 million a year cost to beekeepers from wasps attacking honey bees, robbing their honey and destroying hives.
  • Wasp-related traffic accidents estimated to cost $1.4 million a year.
  • Over $1 million each year spent on health costs from wasp stings.
  • On top of the direct costs, almost $60 million a year is lost in unrealised honey production from beech forest honeydew which is currently being monopolised by wasps. Honeydew is also a valuable energy source for kaka, tui and bellbirds.
DOC Scientist Eric Edwards said these numbers are conservative. The actual cost of wasps is much higher especially if you take into account the impact on tourism and our love of the outdoors, which this study wasn’t  able to measure in full. 
“It’s hard to put a dollar value on people’s  attitudes to wasps and to what extent wasps prevent them from visiting conservation land or taking part in outdoor tourism activities,” he said.
“Wasps are a massive annoyance and their multiple stings can cause a lifetime effect of making young people reluctant to return to forests and parks.” 
The Ministry for Primary Industries (MPI) Dr Erik van Eyndhoven said that reducing wasp abundance would produce major flow on benefits to pastoral farming and horticulture through increased bee pollination services.
“This study shows it makes economic sense,  as well as environmental sense, to invest in research to control wasps,” he said.
“MPI is working with DOC to encourage the science community, and their funders, to further explore a range of tools needed to control wasps in the long term,” Dr van Eyndhoven said. The MPI Sustainable Farming Fund has recently supported investigations into the bio control potential of a new mite discovered in wasp nests. And DOC has been actively working on a programme to better control wasps and has been piloting a targeted bait station method on conservation land.
An evaluation of the cost of pest wasps (Vespula species) in New Zealand, by the Sapere Research Group, was jointly funded by the Department of Conservation and the Ministry for Primary Industries. 


Published in Issue 164
Sunday, 25 February 2018 09:58

Ferret lured by sardine juice

This trapped ferret is located in a fenced area adjacent to part of the wetland, note the sprayed access to the trap.

The ferret must have liked the smell of the juice from the ‘Sardines in Springwater’. Note the colour of the ferret, mostly white.

Another hedgehog trap used, DO 200 (pic right). Blackbirds use the top of the trap to crack the snail shells on. It is awash of snail ‘juice’, for the want of a better word, and the trap is surrounded by empty snail shells, sometimes this activity sets the trap off.
Published in Issue 165
Friday, 23 February 2018 08:12

Running the trap line…

Predators and pests - battle continues
and that includes rats and mice…

Not an exact science – but  getting better.

It never ceases to amaze me a the continuing number of predators/pests that are dispatched on a yearly basis at “The Patch”, a western coastal wetland an dune property, southern North Island where I have lived for 27 years.

For a number of years we did not record the numbers dispatched, albeit with one Tims trap early on we did account for around 35 ferrets over three years.

However in February of 2008, a record was started. To date that list, which is compiled from mainly pests that my dogs find with others like the hares that keen hunters dispatch and me on a wasp run over the summers read like this: 301 hedgehogs, 131 hares, 37 possums, 40 wasp nests, 4 stoats/weasels, 1 ferret and 10 “others” mice, rats etc. I also run five bait stations for rats/mice.

In May 2009, with the appreciated assistance of Greater Wellington Regional Council, a number of DoC 200 traps were provided to me  and other adjacent wetland owners. I have six of the traps here, located mainly around the wetland areas of the property. In the time since they have accounted for an additional 75 hedgehogs, 80 stoats/weasels, with weasels being the predominate catch, 2 ferrets, 46 rats, 15 mice, a grand total since February 2008 of 742 ‘items’.

Of note, we have not found/shot a possum for over three years, albeit recently during an ‘agency’ initiative three were accounted for on a neighbouring property. What we have found though is that after a run of catching mustelids, the rat numbers go up for a bit an lately the hare count has been high, 17 in four weeks and eight on the run sighted on afternoon. We do consider that bird number, particularly pheasants have increased over recent years. With the ducks it is harder to make a comparison as water levels also pay a very important part in their survival due to hawks and pukeko.

For my traps I use the juice from Sardines in spring water. I have a small sealed container kept in the fridge, when I have about three to  four lots combined it is enough to do a round, once every three months is enough. It is easy  to drip into the trap box. I aim for under the  treadle plate or down the side of the box past the treadle plate, no need to open the trap as it can be tilted up.

The lead into the traps is bare, I have found that keeping this sprayed is best, and also the area around the trap as I consider it allows the breeze to whisk the smell away over the wider area. Note the trap with the hedgehog is has been used extensively by blackbirds to crack snail shells on. Snail juice stains the trap top and snail shells litter the surrounds. One negative of this is that activity by the blackbirds sometimes sets the trap off.

While we now trap very few ferrets, one - an albino is in the photo, also had another earlier in the year. I keep the traps located just inside a fenced margin, firstly just far enough in so that inquisitive  stock don’t set it off, but I also consider that the mustelids do run the margins so the traps are located in that zone. I did widen out the mesh openings to the traps from 3 x 3 squares to 4 x 4 as I found we were not catching big hedgehogs – which we do now.

Ian Jensen

Published in Issue 166
Friday, 23 February 2018 07:12

Pukaha Mt Bruce ups the anti on Predators

New self re-setting traps for Pukaha

Pukaha has been looking at a wider range of options for predator control in the reserve and the surrounding buffer zone. Then thanks to a generous donation from Pub Charity, they were able to purchase a number of A24 self resetting stoat and rat traps.

You can check them out at

The initial consignment of traps are for their buffer zone provided by the Greater Wellington Regional Council and are also near the aviaries at the Visitor Centre. This February they will be rolling out these devices into their ‘front face’ to supplement the current DoC 250 traps.

The total number of rats caught in the 12 month period September 2014 - September 2015 in both the reserve and buffer zone was 1530. The number of mustelids (weasels, stoats and ferrets) was 104.

Pukaha are continuing to look at innovative predator control techniques and will keep supporters updated on progress.


Concrete, concrete and more concrete was the order of the day when the footing was laid for the  new free flight aviary. The construction was underway thanks to the teams at Rigg-Zschokke Ltd and Higgins Contractors, The team at Puckaha Mt Bruce were hoping that all going to plan they are aiming for an opening date in late February 2016.

Published in Issue 166
Thursday, 22 February 2018 07:55

Keep alert – invaders are everywhere

Keep alert – invaders are everywhere

No 1: Velvertleaf.

As of Wednesday April 20, Velvetleaf had  been confirmed on 196 properties in 11 regions of New Zealand. This number is expected to increase as the Ministry for Primary Industries (MPI) continue to visit properties in Otago and Southland known to have planted the Kyros or Bangor fodder beet varieties. 

More and more unwanted problems and pests are invading out lovely country. We need to be alert and make sure caring people like Ducks Unlimited members keep a look out for problems.

Velvetleaf is one of the world’s worst cropping weeds and it is just about everywhere fodder beet has been planted this season.

Velvertleaf is an annual board leafed herb that grows up to 2.5m tall. It has large heart shaped leaves, velverty to the touch. It flowers from  spring through to autumn with yellow flowers  about 3cm across.

It crows in crops, if you think it might be  on your place contact Ministry for Primary Industries (MPI) 0800 08 99 66. Advice it not to pull up the plants but contact MPI.

No 2: Honeybees.

Our little helpers are in danger of memory deficits and learning. Even low levels of pesticide can harm the bees. It means they lose the ability to recall odours and worse they lose their odour-learning abilities.

Bees rely on memory to target flowers, but exposure to various sprays appears to be stunting their effectiveness as nectar foragers and pollinators.

Researchers at Otago University tested bees from 51 hives at 17 sites in Otago and tested their pesticide chlorphyrifos levels. Low levels of the pesticide were found in bees at three ofthe sites.

In 2013 the team from Otago’s Department of Chemistry showed chlorpyrifos was detectable in air, water and plant samples, and even in non-sprayed areas as it had a high ability to volatilise and travel great distances.

Most uses of the chemical have been banned in Britain since April 1 this year.

No 3: Blackgrass.

Now there is Blackgrass. It was detected  during routine sampling of rye grass seed in Canterbury in February.

It seems to be an isolated incident, but farmers should stay alert and are urged that a thorough investigation should be undertaken to trace all potentially contaminated material.

Blackgrass is an invasive plant that is difficult to contain once it spreads. It competes with winter crops for light, nutrients, space and water, resulting in yield loss and increased cultivation costs that could be potentially devastating to the New Zealand Arable Industry.

Published in Issue 167