A severe mouse plague is sweeping through large parts of Australia, destroying crops, invading homes, and disrupting schools, with farmers and scientists describing the infestation as one of the worst on record. The outbreak is concentrated in the northern and southern cropping zones of Western Australia and South Australia, where researchers from Australia's national science agency, CSIRO, have recorded thousands of active mouse burrows per hectare — far beyond the 800-per-hectare threshold that officially defines a plague.

The crisis has its roots in last year's record-breaking harvest. When grain is processed in large quantities, significant amounts spill onto paddock floors, creating an abundant food source for mice. A subsequent bout of summer rainfall then encouraged fresh plant growth, providing the rodents with what one Western Australian farmer described as "steak and salad" — ideal conditions for a population explosion. Mice reach sexual maturity at just six weeks old and can produce six to ten offspring every three weeks, with females falling pregnant again within days of giving birth, making infestations extraordinarily difficult to contain.

For farmers, the timing is particularly damaging. Autumn is the critical planting season for grain crops, and mice are consuming freshly sown seeds directly from the furrows overnight. Farmers who do not apply poison bait immediately after seeding can find entire rows of crop missing by morning. The cost of re-planting, purchasing bait, and repairing gnawed machinery wiring and hoses runs into hundreds of thousands of dollars — burdens that compound already elevated fuel and fertiliser prices linked to disruptions in global energy markets. The psychological toll is also significant: unlike a drought, a mouse plague follows farmers indoors, with rodents running across beds and raiding kitchen cupboards through the night.

The disruption extends beyond farms. Schools across rural Western Australia are also struggling, with teachers required to don protective suits before classes to clean classrooms of droppings and dead mice. One school in Morawa, a town roughly 370 kilometres north of Perth, was temporarily closed after an unauthorised pesticide was used inside the building. Education authorities have established a dedicated taskforce to support affected schools, which face staff shortages and an acute shortage of cleaners. Some schools have reportedly adapted to the crisis by incorporating the infestation into lessons — using mouse reproduction rates as a subject for mathematics classes.

Relief may be approaching. Regulators have recently approved a stronger rodent bait, which farmers have been seeking for months, and cooler winter temperatures are expected to slow breeding rates. Farmers in the worst-affected areas report early signs of declining numbers, though the damage already inflicted on this season's crops is unlikely to be fully recovered.