Millions of cannibal mice threaten Australian agriculture amid fears for Sydney

Sydney — The plague of mice attacking parts of Australia is turning into a horror story, with the rodents threatening to invade Sydney, reports of the vermin eating their own, and the farming industry being thrown into turmoil.

Millions of mice have swarmed schools, homes and hospitals in the eastern states of New South Wales and Queensland, wreaking havoc and leaving entire towns suffocating from a lingering pungent odour. Now there are reports of them munching on the remains of dead rodents and even predictions that they could reach Sydney in a matter of weeks, riding on freight trucks and food crates.

While the Australian Pesticides and Veterinary Medicines Authority has not approved the use of a highly toxic chemical to tackle the scourge, the state of New South Wales is already gearing up for the permit. Local authorities have secured 5,000 litres of Bromadiolone, one of the strongest mice killers, for distribution across 20 treatment sites in the worst-affected areas of the region.

The swarm is also threatening Australia’s $51bn agriculture industry. Mice numbers have exploded after a bumper crop last season. With the crisis showing no signs of abating, some farmers are refraining from planting winter crops for fear of damage to freshly sown seeds and ripened grain, according to Matthew Madden, the grains committee chair for industry group NSW Farmers.

“People are actually just abandoning crops because they think, why am I going to plant this if it’s going to get eaten?” he said from his Moree farm in northern New South Wales. “The anxiety is, even if I get it to spring, if these vast numbers are still here they’ll just eat the crop as it ripens.”

Lost tractor

Some sorghum crops harvested earlier this year have sustained significant damage, ranging from 20% to 100% in some fields, Madden said, adding that the grains in storage from last year, if they weren’t eaten, have been subject to contamination from mouse droppings. That’s leading to extra cleaning costs for farmers, or in some cases, outright rejection of shipments at ports.

The financial pain isn’t just confined to farms. Damage to machinery, storage vessels, homes and health of people have also been reported. Madden, who himself recently lost a tractor to fire after mice bit through a live cord, said the devastation could cost hundreds of millions of dollars. Lost opportunity costs are hard to quantify, he added.

“We won’t know until harvest time,” Madden said. “It’s just unimaginable.”

The situation has spiralled ahead of buoyant expectations for a record Australian canola output this year, as a combination of high oilseed prices and optimal weather created perfect conditions for the crop. The disruption to seeding due to the mice in New South Wales has tempered enthusiasm about production this season, according to the Australian Oilseeds Federation.

The risk that the situation will escalate in spring continues to weigh on the outlook. Rodent numbers usually start to dwindle during the colder months heading into winter, but this year has bucked the trend. That’s a problem if numbers keep building ahead of the typical surge during warmer months.

Last year’s plentiful rains, which offered farmers a respite after a prolonged drought, paved the way for an explosion in mice numbers, Madden said.

“Over the drought we didn’t have these issues,” he said. “It’s been a perfect storm.”

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