The mice are everywhere. Each morning, residents of Morawa, a remote town in Western Australia, check for carcasses in the traps they set at bedtime. They inspect their kettles for little bodies before making tea. They wipe down kitchen benches in case rodents visited at night. Then they head to work and do it all again.
The town, about 230 miles north of the state capital of Perth, has been under siege since February. When driving at night, residents say they can hear popping — likening it to Bubble Wrap bursting — as the car wheels crush mice on the road. Returning from vacation, residents found their beds filled with mice, according to local media. Locals say the snakes are fat from overeating.
Many call it the worst mouse plague in living memory.
“They’re everywhere,” said the Morawa Shire president, Karen Chappel. “I’ve experienced a mouse plague in 1975 when I was a young girl, but it was different. It was out in the paddock. It wasn’t in our homes. This time it’s in our homes.”
It is estimated that the plague stretches across a large part of the vast state and extends east into the neighboring region of South Australia.
Living with the influx of rodents has been exhausting for the town’s 660 residents, Ms. Chappel said. The authorities have handed out free baits to help residents manage the surge, because “you can’t afford to have someone who’s not doing it if we want to win the war,” she said.
“We’ve just got to have faith that we will get rid of them at some stage, but it’s a battle,” Ms. Chappel added.
Steve Henry, research officer specializing in mice at the Commonwealth Scientific and Industrial Research Organization, said mouse plagues often start when food is abundant and the weather is dry, as was the case in Western Australia.
A mouse plague is defined as more than 800 mice per hectare, or 320 per acre. In parts of Western Australia, there were an estimated 8,000 rodents per hectare in May. Mice can have up to 10 babies every 19 to 21 days, often giving birth and then falling pregnant a few days later. This pattern allows their populations to explode into the millions very quickly.
“Once they bred up to a certain level, they became impossible to ignore,” Mr. Henry said.
Australia is no stranger to mouse plagues, which typically occur in grain-growing regions. In 2021, parts of New South Wales battled a monthslong plague, where mice invaded homes, farms and businesses, causing millions of dollars in damage. Inmates at a correctional facility were relocated after mice chewed through internal wiring and destroyed ceilings, air conditioning and wall panels.
Mouse plagues can bring increased risk of diseases. In 2021, a farmer nearly died after contracting a type of rodent-borne bacterial meningitis. Mr. Henry said wearing a mask while cleaning up after rodents and washing hands are the best protection.
“In normal times, we don’t interact with them that much, and the risk of them spreading diseases is low,” he said. But during a mouse plague, rates of interaction “go through the roof,” allowing diseases to spread rapidly.
Hope of a Reprieve
After months of setting traps and baits, clearing them and resetting them, Morawa residents say the number of mice is finally declining.
Peter Thornton, who runs a grocery shop and liquor store called Morawa Traders, said he had not caught a mouse in four days. At the height of the plague, mice used to run along the shelves, eat the labels off the alcohol bottles and nibble the stock, he said.
While there are fewer mice, the stench of the dead and the smell of their feces linger, he said.
“It was relentless,” Mr. Thornton said, adding that he was even bitten on the finger while he was sleeping a few months ago.
“They’ll die under a fridge or something like that, so we’re constantly moving furniture around to try and find where it’s all coming from. So, it gets a bit weary after a while,” he said. “We’ll get through it.”
Australia and China are the only two countries where mouse plagues occur, although scientists are not sure why.
As winter sweeps across the Southern Hemisphere, Mr. Henry said the mice would stop breeding and their numbers would decline further. But the real test will be when the warmer weather returns in spring.
Plagues can have lasting economic and mental effects, including post-traumatic stress syndrome, long after the mice have left.
Ashley James, a farmer who lives outside Morawa, has spent more than $31,500 trying to get on top of the mice at his 14,800-acre property. That includes the cost of the poison and hiring extra hands to lay bait — farmers are allowed to use stronger toxins. It is money he hadn’t planned on spending.
The mice have chewed through the wiring of old tractors, and he’s worried they’ve ruined other pieces of equipment. But Mr. James’s biggest concern is that they will return in the warmer months.
“You’ve got to be watching all the time,” he added.
