Rabbits were brought to New Zealand in the 19th century, for food and sport.
Rabbits breed quickly – one female can have 45 babies in a year, and numbers can increase eight- or tenfold in a season.
Plagues of rabbits
New Zealand has had several rabbit plagues. In the South Island, rabbits became a major problem in Marlborough, Canterbury, Southland and Otago. In the North Island they spread mainly in Hawke’s Bay and Wairarapa.
The impact of rabbits
Plagues of rabbits are a serious problem on farms, as they eat the plants that would provide food for sheep. The farms then produce less wool and meat, and lose money. In some parts of Otago, farmers had to abandon their sheep runs because they were overrun by thousands of rabbits.
Rabbits also damage the environment. In drier areas, they have eaten all the plant cover, and it has not grown back. The exposed soil is prone to erosion by wind and rain. Rabbits’ burrows can also cause erosion.
Trying to control rabbits
Farmers and the government have spent millions of dollars trying to get rid of rabbits. Until the 1950s, the skins or meat of dead rabbits were sold to Britain.
Methods that have been tried include:
- hunting with dogs
- poison – sometimes mixed with grain, carrots, apples or jam, and sometimes dropped from aeroplanes
- pumping poison gas into burrows
- building fences from wire netting to keep rabbits out. Some rabbit fences were very long – more than 130 kilometres
- using predators such as ferrets, stoats and weasels. These were released in New Zealand, but they hunted native birds, and did not kill as many rabbits as expected
- deliberately spreading diseases that kill rabbits. One disease, myxomatosis, was brought into New Zealand in 1952, but did not become established. In 1997, some farmers released rabbit haemorrhagic disease (RHD), against the wishes of the government. This killed many rabbits, but they are now starting to become immune.
None of these methods has been completely successful. Rabbits are still a big problem for New Zealand farmers.