What does it look like?
Possums are furry marsupials of medium to stout build with thick, bushy tails. Their bodies are 38-45cm long (65-95cm long including the tail). Their weight varies greatly but averages around 2-3kg. There are two main colour forms - grey and black. Possums have large eyes and catlike whiskers, which are characteristic of nocturnal animals.
Possums can live anywhere that has shelter and a varied food supply. Forests are their favoured habitat, but forest/pasture margins can also support very dense populations of possums. Possums feed mainly on leaves but also take buds, flowers, fruits, ferns, bark, fungi, invertebrates (including land snails and weta), native birds and their eggs, and carrion. They are nocturnal, but starving or sick animals may emerge to feed in the afternoon.
Why is it a problem?
Possums can occupy a range of habitats and can survive on poor or irregular food supplies. By eating plant foliage, they damage and destroy forests and affect pasture, vegetable, and horticultural crops. Possums can be a vector in the spread of diseases (like tuberculosis) that affect domestic animals and humans.
Possum populations expand their range by the gradual spread of female offspring on the edge of occupied home ranges. Their ability to produce more than one offspring per year and the enhanced survival of juvenile females when conditions are good, allows possum populations to increase rapidly in newly invaded areas or after populations have been reduced by control pressure.
The average life span of a possum is 7 to 10 years. Most female possums breed from one year of age and can produce one or, less commonly, two young in a season if food supplies are adequate. Young possums spend the first part of their life in their mother’s pouch, feeding on rich milk. After weaning at 5-8 months, young females tend to remain close to their mother’s home range. Young males disperse randomly in search of receptive females and have been recorded migrating between 0.5 to 20 kilometres.
Control methods
Options:
Trapping
Poisoning (bait stations)
Shooting
Trapping
There are two main types of possum traps – live capture or kill traps. As with poisons, each has advantages and disadvantages depending on the situation.
Kill traps
There are many different designs, but the principle is to quickly and humanely kill the possum. Some traps are better than others and often the way the trap is set can make a difference to its effectiveness. Timms traps are effective, affordable, easy to set, and are one of the most common kill traps available. Other possum traps include the Flipping Timmy, the Possum Master and the self-resetting AT220 NZAutotrap. More information about these traps can be found at the trapping link at the bottom of the page. To save money, we recommend purchasing from the manufacturers rather than other retailers.
The main advantage of kill traps is that they don't need to be checked daily. Traps may be left in place for long periods but are only cost-effective as a short-term control technique. Kill traps are seen as a risk to domestic cats however risk can be reduced by using baits which cats won't eat (such as fruit) or by keeping cats indoors while traps are set. Traps can also become weak or worn over time and lessen the ability kill humanely. Possums can also become trap shy if kill traps are not set correctly and they can be dangerous to other non-target species for the same reason.
Live capture traps
There are two main types of live capture traps. The first is usually a box or cage which is baited to lure an animal in, then the door is activated to close and lock behind it. The second are leg-hold traps which are small steel spring-loaded jaws that clamp and hold the possum's leg just above the paw when it stands on the trap.
Box or cage traps usually work well around built areas where non-target species may be at risk. Trap-shy animals can also be lured in by pre-baiting around the outside of the trap with favoured bait. Animals caught are unharmed but must be humanely disposed of. (It is important to note that drowning, once a common method, is now considered inhumane and has been made illegal).
Leg-hold traps have a long history of being very effective at catching possums for both control and the fur trade. Leg hold traps with serrated jaws and large traps with unpadded jaws are now banned. To help prevent accidental capture of Kiwi, all leg-holds need to be set 70cm of the ground in areas where kiwi may be present. Also, as protection for cats, no leg-hold trap may be set within 150 metres of a dwelling without permission from the occupier.
Legal requirements:
A person who, for the purpose of capturing alive, a mammal, bird, reptile, or amphibian, sets a trap or causes a trap to be set must inspect the trap, or cause a competent person to inspect that trap, within 12 hours after sunrise on each day the trap remains set, beginning on the day immediately after the day on which the trap is set.
Check local bylaws before trapping. For example, leg-holds are not permitted in the Napier City Council area of Hawke’s Bay.
Poisoning
Poisoning is the most cost-effective way of controlling possum populations. The use of specially designed bait stations also ensure that control is carried out in a safe, effective way that does not put other non-target animals (i.e pets or birds) at risk.
Bait stations come in a variety of shapes, sizes, and prices. Key features to look for are how well it will weather, how easily filled and how easy possums can feed from it. A bait station protects the bait from the weather which increases the effective life of the poison.
Regional Council cap the costs for Regional Council pre-approved contractors to re-service rural properties which are within the PCA (Possum Control Area) programme. The cap limits costs to $3/ha following initial setup at the occupier’s expense.
For more information, contact us on 06 835 9200.
Shooting
Shooting possums at night using a spotlight is a popular method of control in semi-open areas where access at night is easy. The red eye reflections of a possum can be easily seen, and by knowing the seasonal feeding habits and targeting these areas, possums can be controlled.
Target prey Sp. Calendar
However, possums can become light shy and avoid hunters. Shooting can also become less effective if over-used particularly when possums are regularly missed.
NB: A VALID NEW ZEALAND FIREARM LICENCE IS REQUIRED UNDER NEW ZEALAND LAW FOR THE USE OF FIREARMS.
More information
Free urban advisory service: At no cost to you, a pest control contractor approved by the Regional Council will visit your property to provide expert advice on the safest and most effective way to remove possums. We will subsidise the control of possums in QEII covenanted land where pre-approved contractors are also undertaking possum control on the land immediately surrounding it.
Answers to Frequently Asked Questions.
What does HBRC Pest Animal Biosecurity entail?
What about TB in HB? HBRC are not responsible for TB monitoring and vector control operations in HB.
For further information, please contact us on 06 835 9200.
Related links
Landowners guide to possum control
Other pest control guides & resources – Bionet.nz
https://pestdss.landcareresearch.co.nz/Possums/Location
Possum control remains the responsibility of the land occupier within the PCA programme.
Legislation related
https://www.hbrc.govt.nz/assets/Document-Library/Plans/Regional-Pest-Management-Strategy/Hawkes-Bay-Regional-Pest-Management-Plan-2018-2038.pdf see page 65 for possums.
Management Programme
Eradication Programme
An Eradication Programme attempts to reduce a pest's level of infestation to zero, across an infestation zone, over a specified time frame. To be successful; the rate of removal must exceed the rate of increase of the pest, reinvasion from other areas must be prevented, and all potentially reproductive individuals must be targeted. For these reasons, eradication programmes require robust design, efficient implementation, sufficient money, and trained field staff to be successful.
More informationSite-led Pest Programme
Pests listed under the site-led programmes, and most of the other pests included in the RPMP, are capable of damaging habitats and important ecosystem processes, or competing with indigenous species for food, or prey directly on native species. Pest management, habitat protection (e.g. via fencing) and habitat restoration/creation (e.g. via planting) are key management measures in halting biodiversity decline in Hawkes Bay. A site-led management programme significantly assists with the delivery of each of these goals.
More informationSustained Control Programme
Sustained Control exists to hold well-established pests at an acceptable maximum. However, the costs of management and control grow in-step with the size of the invasive population. Because cost:benefit returns can fall to 1:5 or less, most of this work is focused on specific sites of high ecological value. While the spread of these pests between neighbouring properties remains the predominant risk, in some cases control within properties is still sought and warranted. A sustained control programme will hold populations to maximum acceptable limits over the period of the RPMP.
More informationUnwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
More informationRules
Plan rule 14
An occupier within a Possum Control Area shall maintain possum densities on their land at or below 4% residual trap catch, in accordance with the Hawke's Bay Regional Possum Control Technical Protocol (PN4969).
More informationPlan Rule 15
Except where an occupier of land has entered into a Written Management Agreement approved by Hawke's Bay Regional Council, an occupier within, or adjacent to, a Possum Control Area, shall, on receipt of a written direction from an Authorised Person maintain possum densities on their land at or below 4% residual trap catch within 500 metres of the adjoining property boundary where the occupier of the adjoining property is also maintaining possum densities on their land at or below 4% residual trap catch.
More informationPlan Rule 2
All occupiers within a Possum Eradication Area identified in the Hawke's Bay Regional Possum Control Technical Protocol (PN4969) shall maintain possum eradication status in accordance with that Protocol.
More informationSections 52 and 53 of the Biosecurity Act (1993)
No person shall knowingly communicate, cause to be communicated, release, or cause to be released, or otherwise spread any pest or unwanted organism, in accordance with Sections 52 and 53 of the Biosecurity Act 1993
More informationGood Neighbour Rule (GNR)
The "Good Neighbour Rule", under the New Zealand Biosecurity Act (1993), requires occupiers of land to take measures to prevent certain pests from spreading to adjacent properties. There are a number of pests where regulatory control within a property is unwarranted because occupiers make adequate control decisions based on their individual requirements. However, the ease that a pest spreads means that controlling property boundaries may still be required. The Good Neighbour Rule also applies where pest control along a property boundary is deemed inadequate.
More information
