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Australians have waged a war on invasive wild rabbits for 165 years with poison, firearms, bulldozers and explosives, even introducing infections that have dramatically reduced the animals’ numbers.
Yet the rabbit population is rising sharply again, officials and farmers say, igniting fresh fears of crop devastation and prompting Canberra to appoint its first rabbit tsar to get the problem under control.
Wild rabbits pose “the biggest threat” to Australia’s ecosystem, said Heidi Kleinert, who became Australia’s national rabbit management co-ordinator at the Centre for Invasive Species Solutions late last year.
Rabbits cost Australia’s agricultural sector almost A$200mn (US$125mn) a year, according to government figures, but other biosecurity threats — such as bird flu, foot-and-mouth disease and the varroa destructor bee parasite — had taken priority in government efforts in recent years, she said.
“Rabbits have the number-one impact and they are the most destructive,” said Kleinert, who has worked on conservation and state-level rabbit control programmes over the past two decades.
The number of wild rabbits in Australia peaked at 10bn in 1920, when the creatures had spread to 70 per cent of Australia’s landmass, some 5.3mn sq km. The population has declined since then to approximately 200mn, before the recent surge in numbers.
“They’re such successful colonisers,” Kleinert said, noting that one pair of rabbits could become 184 within 18 months, and that females could be impregnated on the same day as giving birth. Rabbit reproduction rates meant they could overrun parts of the country that were thought to be rabbit free very quickly, she added.
Australia’s booming wild rabbit population can be traced to 13 English animals that were released on Christmas Day in 1859. Thomas Austin, a settler who owned an estate near Geelong, Victoria, had the rabbits shipped from his native England and released for a shooting party.
Within seven years, 14,000 animals were spreading across the continent. Farmers and government undertook various efforts to stop their spread and protect native flora and fauna, including the construction of 3,256km of fence in Western Australia.
The release of the disease myxomatosis in 1950 finally began to curtail the rabbits’ numbers dramatically. New viruses were also introduced, such as Calicivirus in the 1990s and K5 virus last decade, and pockets of Australia, including Macquarie Island in the Southern Ocean and Neds Corner estate in Victoria have managed to eradicate the pest.
But biologists and agronomists say new viruses are needed as older variants lose potency. Wet weather in recent years has also provided ideal breeding conditions, leading rabbit numbers to rise again. This has caused panic in the agricultural sector as some crops, including canola, have been ravaged.
Kristin Westlake bought a 120 acre-farm near Jindabyne in Australia’s Alpine Country to raise Dexter cattle with her husband John in 2021. She recently found rabbits had dug under sheds across the property, threatening the structures. “They’re everywhere now. The place is lousy with them,” she said.
Some farmers, facing crop loss and property damage, pour petrol down warrens and set them alight. Westlake said she was planning to bait the rabbits with poisoned carrots and oats, as shooting did not make much of a difference to their numbers.
“It’s not effective, but it does make you feel better,” she said.
Kleinert said the booming rabbit population had also increasingly threatened sacred indigenous sites, including burial places.
Kleinert, who will be in charge of rabbit eradication strategies, training and community outreach, said the campaign required a community-wide approach and that newer generations of farmers might not realise the “collective responsibility” to be vigilant.
“This is not a fix and forget problem,” she said. “It’s not how many rabbits you kill but how many you leave behind.”