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Australian Brushtail possums were first introduced into New Zealand in 1837. They were initially landed in Invercargill by Captain J. Howell with the intention of establishing a fur trade. With no native predators and the native plant life having no natural defense against these browsing mammals there was nothing to stop their breeding out of control.

Landcare Research recently carried out a study to estimate the number of possums in New Zealand. Dr Bruce Warburton announced at the 2009 National Possum Control Agencies conference that he believes there could be as many as 30 million. If control was not undertaken he believes there would be as many as 48 million. The 36% reduction is costing New Zealand around $80 million per annum. Trapping, shooting and poisoning are all used to stem the tide. The complete eradication of possums on Kapiti Island took 6 years and cost many hundreds of thousands of dollars.

Why Are Possums a Pest in New Zealand?

Possums are a threat to New Zealand native flora and fauna, both by destroying the native natural habitats and through direct predation of native plants and animals. Possums have been seen stealing and eating bird eggs.

Possums are very susceptible to bovine Tuberculosis (Tb) and the disease progresses rapidly in possums. Infected possums excrete large quantities of the bacteria and if they are feeding on pasture where cattle or deer also feed there is a great risk of spreading the disease. Thus they are creating a major threat to New Zealand milk and beef exports.

It is estimated that only 10 possums will consume enough pasture to graze one sheep. This means in areas of bush pasture boundary they have a significant economic impact.

Possums eat roses and other garden plants. They will also live in our roof spaces, and given a chance, become a general nuisance around homes and other buildings.

Possums cannot tell the difference between Power Poles or trees, often causing blackouts and personal electrocution. Visitors often ask what the metal bands around poles are for.

Continual browsing on favoured trees could cause the eradication of some unique New Zealand native trees including Rata.

How to Get Rid of Possums From Your Own Property

There are two methods of controlling possums; toxic baits and traps. For each method there are many different products.

Licensed possum control contractors often use a combination of methods from aerially applied baits laced with the controversial toxin 1080 to lines of cyanide baits and leg hold traps. But for the individual farmer, lifestyle block owner or home owner the options are limited to methods that are simpler and more targeted at the smaller property.

Traps

The advantages of traps include low risk of harming non-target animals, no eco-toxicity, you get to see what you have caught and pelts and fur can be collected for sale.

The disadvantages are they are labour intensive, needing re-baited and reset regularly. They also require some skill and knowledge to be set correctly and in the best locations. Most of all they only catch one possum at a time.

There are a variety of trap designs available; leg hold traps, live capture traps and kill traps.

Leg-Hold Traps

Set leg-hold traps where possums travel or beside trees showing possum sign or possum ‘runs’. Rub ‘lure’ behind each trap to help attract possums. Ensure the chain is connected to a solid object such as a tree or post, with as short a length as possible.

Place the traps on level ground, so that trapped animals are not left hanging over steep banks or ledges. Clear away material from around the trap that could injure a struggling animal.

If there is a risk of catching non-target animals such as pets or ground birds such as kiwi place traps on raised boards. Secure the trap chain at a 45 degree angle behind the tree ensuring the chain is long enough to allow the trapped animal to fall to the ground, without being left hanging.

Leg hold traps must be checked at least daily.

Live Capture Traps

Live capture traps (cage traps) can be purchased from most farm supply stores. They are mainly used in urban areas where there is a higher risk of catching pets. Leave new traps outside to weather for a few days before use. Set traps near possum-damaged plants or beside possum runs. Place the trap on firm ground and check that the door closes properly when triggered. Make sure the trap faces the direction possums are most likely to approach from. Ensure the trap is placed so that a possum cannot climb down on top of it, triggering the trapdoor too early. Attach bait to the trigger arm of the trap. Use apple, kiwifruit, orange carrot or manufactured long life bait. Set the trap by lifting the door and holding it open with the trip pin. Insert the trip pin only far enough to prevent a light wind from releasing the door.

Live capture traps must be checked at least daily.

Kill Traps

Kill traps are typically lightweight, cheap and easy to set. They can effectively control possums in small to moderate sized areas, such as urban gardens and lifestyle blocks. The Timms kill trap is a popular example of a kill trap. They can be set on the ground where non-target animals are not present. Make sure traps are secure by pegged to the ground. If non-target animals might be at risk attach the trap to a tree, fence or roof – drill holes into the back and sides of the trap, thread strong cord through the holes and tie to a branch or platform.

When using Timms traps keep your fingers clear of the front opening at all times. Set the traps in late afternoon/early evening and bait with a piece of fruit, such as quarter of a fresh apple or orange, pieces of carrot or long life lure. Do not use meat or fish as bait as it will attract cats to the trap. Keep family pets indoors while the trap is set. Replace fresh bait every two days or use long life bait such as NO Possums non-toxic gel bait.

Disposing of Trapped Possums

In New Zealand it is illegal to release live possums. All live captured possums must be killed humanely. Be very careful when approaching trapped possums as they have sharp claws and teeth.

Dispose of possum carcasses by burying them in your garden, leaving them to decompose in the bush or putting them in your rubbish bag if you live in an urban area.

I recommend the use of traps that have successfully passed the National Animal Welfare Advisory Committee (NAWAC) guidelines for welfare. Go to the Landcare Research website for more information.

The baits used to lure possums into traps include apple, orange, carrot, flavoured flour and icing sugar and some retailed baits. These tend to have short effective lives and need replacing after a few days. There is also Kiwicare NO Possums non-toxic long life gel bait that remains palatable and attractive to possums for months.

Toxic Baits

Unless you possess a poisons licence you must only use toxic baits that are registered for use by un-licensed operators. Cholecalciferol (Vitamin D3) baits do not require a licence and are effective against possums, have low eco-toxicity and pose a low risk to animals that might scavenge of the carcasses of dead possums.

Placement of Bait Stations

All toxic bait should be placed in bait stations, both to reduce the risks to non-target animals and to protect the baits.

Set stations on trees showing possum sign or possum ‘runs’. In areas where there is no risk of dogs, stock, weka or other non-target species feeding on the bait, the stations should be fixed vertically on a tree, post or other suitable surface at about 30cm from the ground. In this position a possum can stand comfortably and feed at the station.

If dogs, stock, weka or other non-target species are likely to enter the area, the stations should be placed at 2 metres or higher, out of their reach. Always follow the instructions supplied with the product. If possible the station should be placed 30cm above a branch or other platform such as a branch so that the possums can still stand comfortably and feed at the station.  A flour blaze or other visual lure can be added to the tree to attract possums to the position of the station. Warning signs supplied must be displayed in areas where the public have access.

Article Brought To You By Kiwicare  kiwicare

Kiwicare is New Zealand’s own manufacturer and distributor of pest control, garden care and home maintenance products. The Kiwicare website contains advice on the eradication and prevention of all sorts of pests that bother us in New Zealand. Learn how to get rid of rats and mice, flies, spiders, ants, cockroaches, fleas, bed bugs and other creepy crawlies. Protect your plants from aphids, grass grub, caterpillars, weeds and more. Keep biting insects at bay with the Safari range of insect repellents. See the BioGro certified organic range of products to help you stay pest free without chemicals.

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  1. The Kiwicare website has a great new look and many new features including interactive problem solvers for home pests and garden pests, diseases and health.
    You may find some of the links in this article try and take you to the page that no longer exists. The error page however will tell you go to the home page and you will easily find the new page on the subject you seek.

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