Stoat killer

New Zealand is plagued by introduced species. There are the big animals like deer and wild pigs [wild pigs are known as "Captain Cookers" because they are believed to have been introduced by Captain Cook], and small ones like stoats and possums.

The big animals are not really a problem. Lots of kiwis hunt [and eat] wild pigs. The Maoris love pig meat.

The small animals are the real problem. Possums were brought from Australia to create a fur trade. There is still a possum fur trade. You can buy all kinds of possum products. I have several pairs of possum and merino wool socks, and very warm they are too. The problem is that there are now about 30 million possums in New Zealand. That would make an awful lot of socks. The possums destroy trees, spread TB and destroy native birds. Their introduction had been a disaster. In Australia they are a protected species, in New Zealand they are a pest. Many trees in Australia have possum defences such as spines, prickles or poisonous leaves and possums in Australia have a lot more parasites, and more predators than in New Zealand.

In hard to reach parts of NZ 1080 poison is dropped by aircraft but the use of 1080 is controversial, not least because some people believe they kill other species as well as possums.

Possum

Stoats were introduced to control another introduced animal, the rabbit. Instead they have wiped out many species of native NZ birds, and have brought others to the verge of extinction. Scientists estimate over 25 million native birds are killed each year by imported predators such as stoats, rats, cats and possums. The people who introduced stoats were warned what would happen but still went ahead. The kiwi has been almost wiped out by stoats.  Like the possum stoats are hard to control by shooting and breed rapidly.


The other solution is trapping, but traps have to be regularly checked and reset after each kill. It is very labour intensive. Now a NZ firm has come up with a new kind of trap. This is gas powered and can kill up to twelve stoats before having to be fitted with a new gas cylinder. Also, its design makes it self clearing. Though the trap costs more to buy the labour costs of supporting it are much less, potentially saving millions of dollars. The traps can also kill rats, another species that kill native birds.

The hope is that the new traps will kill stoats, rats and possums, allowing the number of native birds to increase and protecting trees.

Link to newspaper article.

Link to video.

The Maungatautari Restoration Project provides some indication of what New Zealand could be like if the introduced species could be eliminated.