We’re at the stage of the mouse plague even cats aren’t phased pic.twitter.com/5zXQR9MVOX
— Lucy Thackray (@LucyThack) April 27, 2021
While the rest of the world is still dealing with the global pandemic, mice are inundating farms and towns in eastern Australia.
This plague has been wreaking havoc on crops, damaging building electrical wires, and even biting hospital patients for months, leaving a stench of rodent urine and feces in its wake. The mice are contaminating drinking water supplies, causing illness in some people, and destroying hundreds of thousands of dollars worth of crops grown by farmers who have already been through years of drought, not to mention the pandemic. While this may seem extreme, mouse plagues are a semi-regular occurrence in Australia due to a number of factors. “We’ve had a very wet summer, which has resulted in heavy crop and vegetation growth, resulting in massive amounts of available food for mice,” said Maggie Watson, an environmental scientist at Charles Sturt University.
“Throw in a mild autumn, and these mice are breeding at epidemic levels.”
House mice (Mus musculus) are an introduced species on the continent that has evolved to withstand Australia’s harsh years of drought and thrive once conditions improve.
“In a breeding season, a single pair of mice can produce 500 mice,” says Steve Henry, a research officer at Australia’s national science agency, the CSIRO. However, he claims that outbreaks of this magnitude are uncommon. Unfortunately, poison is the most effective defense against this furry ravenous horde that farmers and residents have. The government of New South Wales, which has been hit the hardest, has requested urgent approval from the Commonwealth regulatory body for bromadiolone, a second-generation pesticide.
However, scientists warn that widespread use of this chemical, which is usually limited to use in and around buildings, will only worsen the situation.
“Second-generation rodenticides can saturate the entire food web, affecting everything from slugs to fish,” Robert Davis and colleagues from Edith Cowan University wrote in The Conversation.
The poison was discovered in tiger snakes that eat frogs, omnivorous skinks that eat vegetation and snails, and a mouse-eating snake with five different poisons, according to their findings.
“Many reptiles – natural mice predators – will bioaccumulate rodenticides, and because reptiles appear to be able to survive a little longer after rodenticide uptake, they become ‘toxic time bombs,’ ready to poison any predator that might eat them,” said Bill Bateman of Curtin University.
Hi Linda, I hope this video might help explain how the mouse problem has got to the extent it has. pic.twitter.com/OL9IOnpVpB
— Ryan Milgate (@ryan_milgate) May 19, 2021
“First-generation rodenticides take longer to work but break down faster, causing less harm to native animals that might eat poisoned mice.” Even desperate farmers are hesitant to use bromadiolone, preferring instead to use the safer zinc phosphide, according to ABC’s Lucy Thackray, who has been following the outbreak closely while mice have infested her own home.
Some farmers, such as Ryan Milgate, are concerned that attempting to avoid Australia’s notorious dust storms is adding to the problem. This is accomplished by leaving the roots of previous crops in the ground to keep the top soil down, which also improves mouse breeding conditions. “Treating house mouse plagues as if the ecosystem were unbalanced isn’t really a feasible option in Australia; they’re just something we have to live with,” Watson said, explaining that Australia had antechinus plagues feasting on locust plagues long before mice arrived.
Due to the continent’s unpredictable rain patterns, environmental ‘boom and bust’ cycles are common in Australia.
To reduce the amount of food available to plague mice, Davis and colleagues recommend that Australia invest in research into grain storage facilities that are less permeable to mice. According to Watson, many mice-eating birds of prey, such as black-shouldered kites, boobook owls, and tawny frogmouths, are in decline due to habitat loss caused by increasing urbanization and broad-acre monoculture cropping.
There’s still no assistance for farmers dealing with the immense costs and damage associated with the mouse plague, which isn’t improving. It’s a huge blow as they’re still very much in recovery mode from the drought. This was filmed by Brody Roche in Tottenham in central NSW. pic.twitter.com/M0Xs3u3DrW
— Lucy Thackray (@LucyThack) March 28, 2021
Predator habitat structures, such as rocky outcrops and remnant vegetation, must therefore be protected. “Birds of prey, native carnivores, snakes, and large lizards are our first line of defense against mouse plagues,” Bateman explained.
As a result, poisoning these predators will only make long-term control of mouse populations more difficult.
Watson told CNN, “You could completely reduce the population of birds of prey.” “It could take 15 to 20 years for them to return, and in the meantime, we don’t have any natural controls in place for the next mouse plague.”
Scientists are researching ways to better manage mouse plagues in Australia. Those who are in the path of the current destructive wave of mammals, on the other hand, require assistance.