Possums are a major pest in New Zealand and are still a growing problem. This report is focused on the bushtail possum and will discuss why possums are a pest, what damage they are doing to New Zealand, and how they can be prevented. Also a different viewpoint on possums and future plans will be included in the following report. Possums are doing a lot of damage to native plants, animals and birds. Although possums do eat a variety of trees, they target New Zealand natives such as the pohutukawa and kowhai trees, and eat them to death.
By eating these native trees, the possums are also eating the homes of New Zealand’s native birds. In addition possums will also disturb nesting birds and occasionally eat their eggs and chicks. Another issue with possums is they carry a harmful disease called tuberculosis. The possums can infect farmer’s cows, cattle, deer or other animals with the disease resulting in sickness and possibly death. Possums are eating up New Zealand. Possums are a small, nocturnal marsupial with grey or brown fur.
They vary in size and weight and can range from 10cm-120cm in length, and can weigh up to 14. kg. Possums are generally the size of a large cat. The bushtail possum was originally brought to New Zealand in 1837 from Australia, for the fur industry. Possums then escaped into the wild where they have become an invasive species. Estimations were, by 1980, that possums occupied 91% of the country, with a total population of approximately 60-70 million, two thirds of which were in the North Island. Possums have no natural enemies in New Zealand, which is why possums have become such a vast population throughout the country.
Possums severely damage native forests by killing the native trees. Possums like to eat new growth on trees, making it very difficult for the tree to grow once all its new growth has been eaten. Also possums will return to the same tree night after night eating the tree until it has been destroyed, which it will then die. Unfortunately possums favour native trees such as the rata and totara trees. This degrades our native forest because many of the trees are not protected with special metal bands that stop possums from climbing and eating away at the tree.
Possums will also disturb nesting birds, and commonly eat their eggs and chicks. Furthermore, possums eat native animals and Insects too such as the native land snail, which are a very endangered species. On top of this, because possums are killing the native trees they are eliminating the homes of New Zealand native birds as well as killing the main source of their food supply. This makes it difficult for the birds to find food, and if this continues in future it will impact on the native bird population. Possums also cause problems in city people’s gardens.
They eat their gardens trees particularly apple, plum, citrus fruit and rose bushes. They also create a lot of noise and have been known to go inside people’s houses. Furthermore, possums spread tuberculosis (TB), which is a disease that attacks the lungs. This results in the animal becoming very sick and for some cases death. TB affects cows and deer in particular. Once infected with TB, the animal is unable to be sent and be killed for export this means possums also has an impact on the income of the country.
Possums need to be urgently controlled. There are several ways of doing this. Some include the following: Bait stations: bait stations are mainly made from plastic and open at the bottom for feeding. They are filled with poison pellets including 1080, cyanide, and pindone. These stations are fixed to trees/posts where possums can easily access the bait. They are placed 30 cm off the ground so ground feeding birds and other animals cannot be affected. Possums then eat some of the poison in the feeder and die.
Bait stations protect the bait from the weather, however if placed on farms, there is a risk cow or pigs could get into the stations. Trapping: Trapping uses cages or boxes with bait on/in them to lure possums in. these traps are designed to kill a pest as it takes the bait. Trapping is an effective method to kill possums although it is time consuming in large areas and not recommended around neighbourhood areas where pets could get trapped. Shooting: tends to be less effective as possums are a smaller pest.
However shooting is an excellent method in rural areas, for example, to reduce the amount of possums on your farm. Hand laid Poisons: these include 1080 and cyanide paste. Hand laid poison can be placed in more areas using smaller amounts of bait. Also it is less costly and does not need re-checking after bait has been laid. Hand laid bait is not as weatherproof and dose not last ass long as it would in a bait station. Considering this there has been long life products developed for bait bags. Pest proof fences: pest proof fences have been designed to stop possums from getting into certain areas.
They are costly though and does need maintenance however they are successful in crating possum free zones. Possum control methods are not as good as they could be. Primarily this is due to the need to poison possums to maintain effective control, as this is the cheapest and most effective option. Prevention: Possums can be prevented from destroying trees by protecting the trees by placing wide metal strips around the trunk of the tree around 1m from the ground. This stops possums from climbing the tree and eating its leaves.
Also eliminate possible nesting sites. Possums look for dry dark sites for example, woodsheds or barns. Block holes to prevent possums from nesting there. At the moment, a biological control method is being researched. This involves wether the possums DNA can be changed to stop possums from having offspring. Unfortunately, because this requires genetic engineering, the research is controversial and to some conservationists, is not approved. Until then, control methods involving less poison are being researched and have produced some useful results already.
To New Zealand, possums are a pest. However they are native to Australia and are protected. Unlike New Zealand, in Australia, possums have natural enemies, and a harsher environment, which contributes to the reason there are less possums in Australia. Possums cannot be personally destroyed in Australia, only by an approved person, such a vet. As a native wildlife species, possums are legally protected under the various state-based wildlife legislation, such as the wildlife act 1975. Possums have become an immensely populated pest in New Zealand.
They are destroying our native forests by eating and killing the trees. They are disturbing our native birds, and eating native insects. Possums are also spreading Tuberculosis, which is infecting farmers stock enabling the animals to be sent for export. A Biological control method is desperately required for the future and may be the answer for controlling or to help eradicate possums in New Zealand. DoC is desperately trying to control the millions of possums in New Zealand although possums will still be highly populated in the near future.