A pesky pest
There are about 30 million possums in New Zealand - that's about 7 per person! Possums will munch through around 9,000 tonnes of leaves, berries and fruit every night.
Possums are not native to New Zealand.
- The first possums were brought to New Zealand in 1837 from Australia.
- Possums are native to Australia and are protected there.
- Many trees in Australia have possum defences such as spines, prickles or poisonous leaves – ours don’t!
- Possums in Australia have a lot more parasites, and more predators than in New Zealand.
In New Zealand possums have no natural enemies. That is why possum numbers increased so fast. The possum is not protected in New Zealand, it is a pest. The possum is doing a lot of damage to the native plants, animals and birds.
So why did people bring possums to New Zealand?
Possums were brought to New Zealand to start a fur industry. At the height of the fur trade, trappers killed 20 million possums in a year. But that did not make much of a dent in possum numbers. Possum numbers can build up quickly because every mother possum has a baby each year.
People didn't realise the harm possums would cause to the forest and the wildlife would be much greater than any value their fur provided!
Possums like to eat the juicy new growth on trees - it is very hard for the tree to grow when all of its new growth is being eaten. In New Zealand forests possums will go back to the same tree night after night, eating the tree to death. They love eating our native trees such as our pohutukawa, rata, totara, kowhai and kohekohe.
Because possums are eating native trees they are eating the food of New Zealand native birds - this is not good for the birds.
Possums are home-wreckers. Not only do they literally eat the homes of native birds, (i,.e the trees), they will eat the eggs and chicks of our native birds. What’s more they have been known to push kiwi out of their burrows so they can have a dry place to sleep!
These pests can also be a problem for farmers too. Possums can spread a disease called 'bovine tuberculosis' to cows, cattle and deer. If the farmer's animals get tuberculosis they will get get a bad cough, and become weak. They may even die.Possums are noisy creatures. Did you know that a possum can make 22 vocal sounds. They do screeches, grunts, hisses, chatters, zook-zook, squeaks and clicks. Take a listen for yourself(see above)
These pictures show the damage possums can do.
The tree was being eaten to death by possums, that's why it looks like it is dying in the picture on the left - that was before the possum control!
Two years later, after the possums were killed the tree was healthy again - that's it on the right with all its new leaves. Both pictures show the same tree.
War on possums!
In the 1940s, New Zealand declared war on possums.
Millions of dollars have been spent trying to get rid of possums to protect the New Zealand environment from possum destruction since.....
- DoC staff have also been busy getting rid of possums in New Zealand's national parks and conservation land through baiting and trapping.
- Farmers, conservationists regional councils, land owners and businesses have also been working hard by setting traps and laying bait to kill possums.
- The staff at the Department of Conservation and Landcare have been doing research about possums to learn the best ways to kill them or stop them from having babies.