Possums

Introduced to New Zealand between 1837 and 1898, possums are today considered to be the major ecological and agricultural vertebrate animal pest in New Zealand.

Possum Photo credit Brisbane City CouncilPossums are an economic and environmental threat to New Zealand as they carry and spread Bovine tuberculosis (Tb) and destroy native and exotic trees, native birds and native invertebrates.

Possums live in a wide variety of habitats, as they only need cover for nesting and a suitable and varied food supply. They can be found in all types of indigenous forest from sea level to tree line, in scrublands, grasslands, exotic forests, shelter belts, orchards and cropping areas, thermal regions, swaps, sand dunes and in urban and city areas. Forest pasture margins however are their preferred habitat, particularly in mixed hardwood forests. They are currently spread widely across New Zealand.

Extensive possum control is carried out by the Department of Conservation (DOC) to reduce the effects of possums on protected public conservation land. TBfree New Zealand controls possums in order to eradicate bovine TB. In many cases, councils and these agencies work together to manage possums.

There are three main options for controlling possums on your land. For specific information in your area and to get assistance in controlling possums, contact your local regional council.  

Methods of control 

Trapping

For welfare performance of animal traps go to https://www.bionet.nz/control/pests-under-management/performance-traps/

In urban areas or close to houses, trapping is the best option for possum control, since neither shooting nor poisons are appropriate for safety reasons. As there are restrictions around the use of leg-hold traps close to dwellings or where pets are present, kill traps may be a good alternative. By law, live capture and leg-hold traps must be checked every day but kill traps can be checked when necessary. Check out your local council for more information and help when deciding what trap to use for your circumstance.

For a list of legal requirements check out the legal requirements page

Poisoning

Using poison baits is generally less labour intensive than trapping so it can be a more feasible option for sustained control operations and control in large, remote areas. Some poisons require a Controlled Substance Licence. For more information about this licence and application forms, visit www.epa.govt.nz or www.business.govt.nz/worksafe.

Poisons are usually put in bait stations, which helps keep the bait dry and away from non-target animals. By initially filling bait stations with a non-toxic form of the bait you intend to use (pre-feeding), you’ll get a higher kill rate when using fast acting poisons like sodium nitrite and cholecalciferol. A pre-feed around one week before placing poison baits should be enough. Most baits used in pest control are not designed to last for long periods in bait stations. If not clearly stated on the product label, remove, replace and dispose of remaining bait after about one month. Bait stations are best spaced 50 - 100 metres apart along well-defined bush/ pasture margins or along tracks through larger areas of forest.

Toxins registered for possums include cyanide pastes and cyanide Feratox, cholicalciferol, 1080, brodifacoum, and pindone. Brodifacoum, cholecalciferol and pindone are the only possum poisons that do not need a Controlled Substance Licence but you are required by law to use these baits only in bait stations to reduce the risks to non-target species and to put up warning signs. 

Signage 

Signage for Brodifacoum: Signs must state that bait is used for possum control using bait stations. Signs must be erected at every normal point of entry and in prominent places on the perimeter of the treatment area. Signs must remain in place for a minimum of 9 months after baiting has ceased but on lands to which the public ordinarily has access, signs must remain in place for 12 months after baits have been retrieved or are no longer present. As well as warning of the danger signs must state that it is an offence for any person to remove the signs prior to clearance of the area, state that it is an offence for any person (other than the operator) to remove baits from the area, warn of the potential harm to dogs, andwarn that feral animals may contain residues and must not be taken for food.

Signage for Pindone: Provided Pindone is used in well-contained ground-based applications using bait stations, signs are only required when it is laid outdoors on land to which the public ordinarily has access. Signs must be erected at every normal point of entry to the public place. Signs must remain for 2 months after baits have been retrieved or, if baits are not retrieved, signs must remain for 8 months after the last baits were applied (no signage required on private land).

Signage for Cholecalciferol applied in biodegradable bait bags: Signs need to be used only when laid outdoors on land to which the public ordinarily has access. Signs must be erected and remain in place until baits are no longer toxic, but must remain for no less than 4 months after the last application of bait.

Signage for Cholecalciferol applied in bait stations: Signs need to be used only when laid outdoors on land to which the public ordinarily has access.Signs must be erected and remain in place for no less than 3 months after baits have been retrieved or are no longer present. 

For further specific information on the control of possums as well as the use of other poisons check out 'Private land owners' guide to possum control: Control tools and techniques' in the Library. 

Disclaimer: Any product names mentioned above are not an endorsement nor are they a criticism of similar products not mentioned. Avoid prolonged use of brodifacoum (Talon and Pestoff) which is persistent in the environment and has secondary poisoning effects which can be detrimental to many species in the food chain. Cyanide, phosphorous, PindoneTM (possum and rats) and 1080 are deadly poisons. A licence is required to store, handle and use these poisons. For more information on obtaining a licence, contact WorkSafe New Zealand.

Shooting

Shooting helps to maintain low possum numbers. Every person who is shooting must either hold a firearms licence, or be under the supervision of a person who holds a firearms licence. You should inform your neighbours of where and when you intend to be shooting. Shooting possums can be an effective control method in small orchards and stands of trees surrounded by pasture. As it is more labour-intensive, it is usually significantly more expensive than poisoning and trapping and is not economic for larger areas.

Monitoring 

To gauge the success of your possum control operation, use wax blocks or ‘chew’ tags and record the number trapped or shot. Annual observations of possum browse or photopoints of trees favoured by possums such as kohekohe, mahoe, puriri, rata, pohutukawa and tree fuchsia will help to determine if your native forest is recovering.

Legal requirements 

Certain traps and poisons can be used in only some areas. You should be aware of local by-laws that might restrict the options available to you for controlling possums on your property. For example, in most urban areas poisons and leg-hold traps are not permitted. In areas with ground-dwelling birds such as kiwi and weka, precautions should be taken such as raising traps or bait stations above the ground.

If you are trapping, you should be familiar with the restrictions of the Animal Welfare Act (1999). It requires that all live traps and leg-hold traps be inspected within 12 hours of sunrise each day they remain set. (Kill traps do not need to be inspected daily.) Trapped possums must be removed and killed as soon as possible and in a way that minimises pain and suffering. You also need to know which traps can be legally used and which traps have been banned.

If you wish to use cyanide, you must obtain a controlled substances license for cyanide use and follow licensing requirements.

For a list of legal requirements check out the legal requirements page

More information 

Get the tools and guidance you need for your community PF2050 project. Includes beginner tips, trap and bait profiles, how-tos and funding resources.

Disclaimer

The information on this website is intended to provide information about pests and pest management in New Zealand. We've made every effort to make sure that the information set out in this website is accurate. If you have an update to the information listed here please contact us.

Photo credit: Brisbane City Council