In the spotlight
Protecting kiwi when setting possum traps
Media release from DoC on 30 April 2013
Possum trapping increases during winter and with the season fast approaching it is timely to remind people that possum traps can endanger kiwi if they are not used correctly. Our area has a prevalence of kiwi and we need to keep them safe.
‘Leg hold’ traps are used by conservation organisations and private individuals for the ground control of possums or for the collection of possum fur. Conservation staff use simple methods that protect kiwi from the traps and strongly encourage private trappers to also follow these two simple methods:
1. Raise the trap above the ground
You can help protect kiwi in our region by raising the trap off the ground by 35 cm. This will prevent kiwi from walking over a trap and being caught. This will not impact on the efficiency of the trap as possums will still reach up and get caught in the trap. To raise the trap you can either use two nails to attach trap to a tree or use wooden boards to sit the trap on top of. In other regions where weka are present we advice raising traps to 70 cm.
2. Use only legal traps and check regularly
Some traps (including the commonly known ‘gin traps) are illegal following amendments to the Animal Welfare Act (1999). It is also an offence under the Act to set traps within 150 metres of any dwelling or to leave traps uninspected for more than 12 hours after sunrise on each day the trap remains set.
These traps are illegal to use:
Lanes Ace (commonly known as Gin trap)
Double-coil spring size 11/2 unpadded.
To protect kiwi from injury please ensure that you take these simple steps. For more information please contact your local DOC office.
Hearing is believing
Do you genuinely care about keeping New Zealand clean and green, but don't know who and what to believe when it comes to 1080? If you want to know the science-based facts about 1080 - what it is, why it's used and exactly what it does - take a moment to read these facts.
What is 1080?
1080 (sodium fluoroacetate) is a naturally-occurring toxin found in many plants throughout the world. Plants have developed it as a natural defence against browsing mammals. The active ingredient in 1080 is found naturally in tea and testing at one site showed it also appears to occur in puha.1 It is manufactured for use in various types of baits for pest control operations and is highly toxic to mammals in particular.
What does it do to the environment?
1080 is highly water soluble and breaks down in the environment into harmless substances.2 It does not accumulate in the food chain or in the soil.3 Any animal ingesting a sub-lethal dose of 1080 will metabolise and eliminate the substance within 10 days.4
Why is it used in New Zealand?
1080 has been used on a small scale in a number of countries, including Australia, the United States and the Galapagos Islands (Equador)5, but its use has been limited because of the need in these countries to protect native mammals. New Zealand, however, unlike almost all other countries, has no native land mammals (except bats)6, but a very large number of introduced, highly destructive mammalian pests, including possums, rabbits, rats, stoats, ferrets and feral cats.7
(Sources: AHB, Nga Manu Images, ORC, ARC, NRC)
Enemy number one
All of these pests have devastating effects on New Zealand's native plants, animals and ecosystems, so conservation is a major motive behind the country's pest control strategy. But enemy number one is also a threat to our pastoral farming, because the possum is the host and carrier of a lethal disease, bovine TB.
Possum and rat invade nest (Source: Nga Manu Images) Click to watch a video of these incredible IR-triggered images
Our natural environment: easy prey for predators
New Zealand's unique flora and fauna is highly vulnerable: it evolved over 80 million years with no browsing or predatory mammals. So it's hardly surprising that introduced mammalian pests - brought here either to be domesticated, by accident, for hunting, for the fur trade, or to control other introduced pests – have driven some of our most vulnerable species to the brink of extinction.
Rat invades nest (Source: Nga Manu Images)
Killers of the night
Possums, rats, ferrets, stoats and feral cats all kill both adult birds and chicks and raid nests for eggs.8 They also compete for, and wipe out, critical food sources for birds such as supplies of berries, flowers, fruits and invertebrates. Predators are blamed for an estimated 61% (26,628,940) of chick and egg losses every year.9
These predators prey on native species that are:
- in immediate danger of extinction: mohua, southern New Zealand dotteral and kakariki
- acutely threatened: rowi/okarito brown kiwi, kaka and North Island kokako
- nationally critical: several species of giant New Zealand snail, Powelliphanta, and
- common species: tui, bellbird, fantail and whitehead.10
Introduced pests have also devastated our forest canopy and stripped vast tracts of native bush. Rata, kamahi, pohutukawa, mistletoe and fuchsia are particularly badly affected.11
It is our unique lack of native land mammals than enables New Zealand to use 1080 aerially, and this has now become a vital tool in the battle to control introduced pests and protect New Zealand's native species. There have been numerous examples of highly successful operations involving the threatened species listed above (see the Case studies section for some examples).
The 'triple predator' benefit
Aerial 1080 operations involving pre-feeding of baits are also increasingly reliable in achieving high kills not only of possums but also rats and stoats via secondary poisioning. This 'triple hit' of the three major bird predators over a large area provides a breeding 'window' for the following season that is crucial to increasing female and chick survival.
Protecting our grasslands
1080 is also a key weapon in the ongoing battle against rabbits, which are now becoming resistant to rabbit hemorrhagic disease (RHD). Farmers and land managers are having to increase their use of 1080 to protect pastoral land from rabbits and preserve the gains made in recent years through the use of RHD.12
Bovine tuberculosis (TB)
Bovine tuberculosis (TB) is a serious, highly infectious disease found in cattle and deer herds, causing weight loss and death.
Possums are the main source and carrier of bovine TB in New Zealand, and the main self-sustaining reservoir of the disease in the wild. In the early 1970s, it was discovered that possums were the source of chronic infection in cattle herds. Bovine tuberculosis infection transfers relatively easily from possums to cattle and deer due to the proximity of farmland to bush areas in New Zealand. Possums are responsible for around 80% of new infection in cattle and deer herds.
Possum with TB lesion (Source: AHB)
Bovine TB is a major threat to our economy
Dairy and meat exports are worth more than $12 billion annually to New Zealand. Rising international animal health standards and growing concern about food safety are now major factors governing and threatening access to premium overseas markets.
Many of our trading competitors, including Australia, are classed as being free of disease.13 As at August 2009, New Zealand had 0.35%14 of cattle and deer herds infected with bovine tuberculosis. This equates to around 131 herds. As a nation with bovine TB infection, New Zealand is banned from exporting live cattle and deer to TB-free countries, including North America and Australia.
Through a nationally coordinated programme comprising ground and aerial control methods and TB-testing cattle and deer, the Animal Health Board (AHB) (the agency charged with controlling bovine tuberculosis in New Zealand) has, in the past decade reduced the number of TB-infected herds by more than 90%. Aerial 1080 operations account for less than 20% of the AHB's control programme, which also uses traps and a range of pest control toxins.
If AHB's bovine TB eradication programme were to stop, the potential cost to New Zealand as a country has been estimated at $5 billion over 10 years.15 AHB is on track to reach the internationally recognised target for official TB freedom of 0.2% infected cattle and deer herds by 2013.
Some facts about 1080 operations
1080 is the only toxin currently registered for use on mainland New Zealand as suitable for aerial targeting of possums.
Aerial application of 1080 using helicopters is a carefully planned process, targeting and avoiding specific areas and boundries using GPS technology.16 Aerial targeting is an essential part of the strategy for reaching areas that are inaccessible or dangerous by land, and protecting TB-free areas throughout the country by creating an effective buffer zone from TB-infected areas.
Ground-based operations are used in about two thirds of the areas where AHB, the Department of Conservation (DOC) and regional councils have identified that possum control is neccessary. Very strict notification procedures are followed prior to all 1080 operations, including the approval of the local public Medical Officer of Health.17
Dogs are very vulnerable to 1080, up to ten times more so than other animals. Dog owners are warned to keep their dogs well away from 1080-treated areas.
In spite of careful procedures, including extensive signposting, occasional dog deaths do occur. Where there is any possible risk, muzzles should be used to protect dogs from eating baits or poisoned carcasses. If a dog inadvertently ingests 1080, it should be taken to a vet immediately. Acetamide has proven an effective emetic and should be administered as soon as possible.18 Farmed mammals and other introduced domestic mammals are also vulnerable to 1080 if they gain access to the baits.
While DOC, AHB and regional councils are all bound by very strict operational regulations and procedures, from time to time accidental poisoning of non-target animals does occur. Avoiding such incidents is a high priority goal and to this end protocols and operating practices are subject to rigorous review and continuous improvement.
The organisations that use 1080 have always been very concerned to ensure that it effectively targets the introduced pests and has minimal impact on native species which they are trying to protect. For example, 30 years ago a standard operation used around 30kg of un-dyed carrot bait per hectare. Today a standard operation would use between 1.5kg and 3kg of dyed ceral bait. Landcare is carrying out research for DOC and AHB to reduce the sowing rate down to just 0.25kg per hectare.19
Alternatives to 1080
The supporters of this website are also supportive of ongoing research into finding alternative methods of controlling possums and other mammalian pests. If we had a choice we would not use some of the toxins that are used to control target pests. Use of any type of toxin involves ethical issues and trade-offs, for example with regard to its humaneness relative to its effectiveness and also the suffering target pests inflict on their prey. Unfortunately, effective solutions involve tough choices, particularly when we are dealing with a major, human-induced threat to our biodiversity and our economy. We have to choose between feeding native and often rare species to introduced pests, or killing the pests so that the native species can survive. We have the same issues with regard to protecting our stock from Bovine TB. We have international as well as national responsibilities to ensure survival of our native species and to protect our farms from disease, and no one can fulfil those responsibilities on our behalf.
Scientists, farmers and conservationists are widely united in the view that for now, 1080 is the best solution we have, and until such time as an effective alternative is found, it must remain a key component of New Zealand’s overall pest control strategy.
The ERMA Review
The Environmental Risk Management Authority (ERMA), is New Zealand's independent public watch dog, and is charged with analysing all actual and perceived risks and perceived risks to the New Zealand environment. During 2007 ERMA undertook a rigorous, comprehensive review of 1080, including a series of nationwide public hearings. All interested parties were invited to present written and oral submissions to an independent committee. The committee spent four months of intensive deliberation, which included an independent analysis of all the scientific data. ERMA concluded that the benefits of using 1080 clearly outweighed the risks, and approved its continued use in aerial and ground applications, subject to strict controls.20
The effectiveness and safety of 1080 as we use it in New Zealand has been the subject of many studies and extensive published scientific research over the past 30 years.
Some key findings
Between 1990 and 2008 extensive water monitoring (2098 samples)21 was undertaken after a large number of aerial 1080 operations. This was a requirement of the Ministry of Health and more recently has been required for ERMA watchlist reporting purposes. The following are examples from the programme:
- After 34 different aerial 1080 operations in the Wanganui area between 1990 and 2008, 76 water tests found no trace of 1080 in any domestic reticulated water supplies.22
- In 2006, a set of trials was conducted in four streams on the West Coast, using 10 times the number of 1080 baits that might normally be expected to enter streams during aerial treatment. These trials showed that even this large number of baits had no detectable effect on aquatic life in streams.23
The conclusion of this extensive water monitoring programme was that there is no risk to human health from the aerial 1080 operations currently being undertaken in New Zealand. Watch a video about water testing here
- Trials show that 1080 is rapidly biodegraded by aquatic and land plants, and by micro-organisms in water and soils.24
- Trials also show that animals ingesting sub-lethal doses of 1080 rapidly excrete the poison or metabolise it into non-toxic products. All traces of the poison in live animals are gone within 10 days.25
- Fish were fed 1080 baits in separate studies in the United States and New Zealand. Of the fish tested in both trials, 100 percent survived and none showed any ill effects.26
- Sausages containing levels of 1080 comparable to those found in a 1080-poisoned possum carcass were also fed to eels in the New Zealand study. After eating all of the sausages, all of the eels survived and none became ill. The eels rapidly eliminated the toxin from their bodies.27
- DOC monitors bird populations and bush health following 1080 applications in many parts of the country. Long-term assessments demonstrate that native bird populations are not damaged by 1080, and indeed that most native bird species show net benefits, especially from the impact of the 'triple predator' by-kill effect of aerial 1080, referred to above. The benefits for native bird populations of effectively taking out three major predators at once are in some cases spectacular.28
- Some inadvertent by-kill of native birds has been recorded, but is more than made up for by the subsequent increase in populations. Kea deaths recorded on the West Coast in 2008 are, however, of real concern, and the Department of Conservation is working with the Kea Conservation Trust on extensive research to determine how to prevent this recurring in future.29
- Monitoring of ground-based insect populations show minimal loss of insect life from 1080, and increase after aerial 1080 targeting as a result of reduced insect predation from introduced mammalian predators.30