Ten mice in your bedroom: Visualising the scale of the mouse plague

Link copiedShareShare articleA mouse plague is invading farms and homes in southern and Western Australia. But what does that really look like? Be warned: if you're squeamish, you may not want to find out. Unless you're in the thick of it, it's hard to wrap your head around what it feels like to live through a mouse plague. Mice breed rapidly in the right conditions and communities in parts of Western Australia and South Australia are dealing with an explosion in numbers. Crops have been damaged, sheds and grain silos overrun, and in some places there are reports the mice are so bad that people have walked out and abandoned their homes. A plague is defined as more than 800 mice per hectare, according to the national science agency, the CSIRO. This square represents a hectare, which is 100 metres by 100 metres. That's about 2.5 acres in the old money. Here's what 800 mice looks like in this space. (Keep in mind: the mice are not perfectly to scale here.) But in some of the worst-hit areas of Western Australia, the numbers are a lot worse. The CSIRO estimates the plague in some farming communities has reached up to 8,000 mice per hectare. Let's face it: this many mice is too hard to count. Instead, scientists count mouse burrows. They've found areas with 40 burrows per 100 square metres, which equates to 4,000 per hectare. Researchers say there are at least two mice per burrow, giving them the 8,000 mice per hectare estimate. If you're not a farmer, you might have trouble thinking about how big a hectare is, so let's take a look at what this mouse plague would look like in some other spaces. We'll start with a rugby or soccer field, which is roughly two-thirds of a hectare. If you're not a footy fan, think instead of a tennis court … Now picture a small, but these days typical, suburban block of about 400 square metres. Here's what this kind of mouse infestation could look like … And if you happened to live in that house, this is what you might share your 3m x 4m bedroom with: about 10 mice. It looks confronting, and for those living through it, it is. Steve Henry, the CSIRO's mouse plague expert, says these events can spark a sense of desperation. "It's the psychological impact. You simply can't get away from them," he says. In Morawa, 370 kilometres north of Perth, shire president Karen Chappel says the mice are inescapable. "We have mice in our homes, we have mice in our cars; they're in our sheds, they're in our paddocks, they're at the school, they're everywhere," she said. "People have had mice bite their toes, people have come home from holiday and there are mice nesting in their beds." The plague zones include the west coast around Geraldton, further south at Merredin and the Esperance region of the south coast in WA, as well as the Adelaide Plains and Yorke Peninsula in South Australia. Mice are also spreading from farmland into towns, where businesses have been inundated, some having to throw out thousands of dollars of stock. Mr Henry says the plague hitting WA is similar to the out-of-control numbers seen in NSW and Queensland in 2021, which caused millions of dollars in damage as well as mental distress. Mice have been running amok on Australian grain farms since the 1880s and plagues tend to break out every four to five years after plentiful rain. The worst recorded plague was in 1993 across South Australia and Victoria, which caused an estimated $96 million damage. Mr Henry says historically WA has not had the same problem with mice numbers as the eastern states, but times have changed. "Over recent years, we're getting more and more accounts of high numbers of mice," he says. "And certainly in the area around Geraldton where mice are so particularly bad at the moment, they've had four really good [cropping] years in the last five. "And we think that's just put a whole lot of food into the system." Farmers are also now fighting back. An emergency permit for double-strength mouse bait for grain paddocks has been issued to get the mice numbers down. Once a mouse eats the bait, it takes about 8 hours for them to die. "When the bait is working well, we expect to see something in the order of 80 per cent or greater reduction in mouse population," Mr Henry says. But he warns the double-strength bait alone won't solve plague numbers. "The effectiveness of it is highly dependent on the amount of other food that's in the system." "It depends on how fast the mice discover those grains that have the bait in amongst all of the other grains that are there." Copy linkFacebookX (formerly Twitter)Related storiesA mouse plague has broken out. Here's what you need to knowTopic:Explainer

Ten mice in your bedroom: Visualising the scale of the mouse plague

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