Why are millions of dollars spent on possum control every year?

The Australian brush tailed possum was introduced into New Zealand in 1837 to establish a fur trade. The possum population flourished here - so much so that their presence has serious implications for farming and for the survival of many of New Zealand's endangered plant and animal species.

Consider these Facts:

• These cute furry marsupials ravage the bush — it has been estimated they chew up seven million tonnes of vegetation a year.
• Possums thrive in the New Zealand environment because they have no natural predators, and the native vegetation is so lush. Because our conditions are so favourable, they often breed twice in one year.
• The number of possums in New Zealand was estimated to be around 30 million in 2008/2009 (a Landcare Research report in 2009 by Warbuton, Cowan and Shepherd), taking into account possum control operations.
• Possums will seek out their favourite food ahead of other species and eat them out to extinction. Some New Zealand plant species such as native red mistletoe, pohutukawa, kohekohe and northern rata are absolute delicacies for possums and are amongst New Zealand's endangered species.
• Once considered vegetarian, it is now well known that possums also eats birds' eggs and chicks. So, as well as destroying our native birds' habitats and food sources, they prey on eggs and chicks of endangered bird species like the kiwi, kokako, and kereru.
• Possums and ferrets are the main wild vectors (or carriers) of bovine Tb in New Zealand, and are a major cause of Tb in cattle and deer herds. It is necessary to reduce the levels of bovine Tb in cattle and farmed deer to minimise the risk of trade barriers being applied to our exports of farm products due to bovine Tb.

Possum Control Works

• After Kapiti Island was made possum free in 1983, vegetation such as kohekohe, rata and fuchsia rapidly recovered. By 1988, recorded bird densities doubled.
• Rangitoto Island had almost lost all of its pohutukawa forest. After 1080 was used, it became a blaze of colour through the summer months and tui and silvereye numbers increased tenfold.
• Native land snails recovered in Kahurangi National Park following an aerial 1080 operation in 1997. In a 500m2 plot, snail numbers increased from 54 to 147, with large numbers of juveniles present.
• Possum control programmes have been the main driver in major reductions in bovine Tb levels in New Zealand's cattle and deer herds.
• Kokako numbers have continued to increase in the Mapara Reserve, in the Waikato, with possum control one of the key factors in the success. In 1989, no kokako chicks were raised. In 1994, after 1080 control, 52 chicks were raised.

Find out how to control possums by looking at our range of best practice animal pest control publications.