Description: The brushtail possum is a furry animal weighing between 2 and 5 kilograms, and has a thick, bushy tail, pointed face, protruding eyes and large ears. It is a nocturnal tree-dweller with long claws to help it grip branches. It was introduced to New Zealand in 1837 for the fur trade. In Australia, the possum is protected as a native species.Possums are found virtually everywhere on mainland New Zealand and Stewart Island, although they have been eradicated from major offshore islands since the early 1990s
Problem: Possums were introduced for the fur trade in New Zealand but that has resulted in an environmental disaster. Endangered in Australia the reverse is true in New Zealand. The New Zealand climate is ideal for the possum and they can breed up to twice a year. There are no natural predators in New Zealand for these animals. In New Zealand the plants have never had to develop defence mechanisms, so all are palatable to the hungry possum. This means that native trees like the rata and pohutukawa are threatened by the possums eating behaviours. They can also vector a disease of cattle – bovine tuberculosis which is a significant disease for farmers to be faced with.
Management: Possum control in New Zealand is managed by the Animal Health Board and the Department of Conservation. Regional Councils are also involved in the management of this pest. Trapping and poisoning are the most common methods of possum control. Shooting is another method of possum control used. On some of the offshore islands and other inland conservation areas predator fences and chemical barriers can be used to keep possums from reinvading once they have been eradicated. Research institutes like AgResearch are investigating biological methods of possum control.
Possum Control Methods:
Poisoning – this is the most effective way of controlling possums over a large area, there are a number of bait and toxin choices, and pros and cons of using each of these
Bait stations are used to keep bait dry and away from other animals and humans. Bait stations need to be regularly monitored to ensure that the possum control is going to plan.
Trapping – this is a common method of controlling possums. There are several different types of traps that are used in possum control. The three most common possum control traps are the live capture trap, the leg hold trap and kill traps such as the Timms and Sentinal traps. Trapping can be used when it is inappropriate to use poisons.
Shooting – is effective but a very labour intensive possum control method, however it is Effective in smaller open areas such as orchards and areas of pasture. Quick, effective and humane.
However it is uneconomic for larger areas as the sole method of control due to high labour costs. Possums become ‘gun-shy’ and will hide away from shooters.