Rural WA concerned about possible mouse plague, as early numbers ramp up to highest levels in nine years

Fears are mounting there could be a horrific mouse plague in rural WA, following a recent explosion in numbers that threatens to derail bumper crops. And while CSIRO’s rodent expert Steve Henry says mice are unlikely to reach plague proportions in Perth, he warns favourable conditions driving bigger populations in rural areas could lead to higher numbers in Perth and other towns and cities. Peter Elliot-Lockhart, agronomist at Elders in Geraldton, said unacceptably high mouse numbers had been reported in crops between Dalwallinu and Ajana, north of Geraldton. Numbers hadn’t been as high at this time of year since 2012. Mr Henry said because CSIRO experts couldn’t “get feet on the ground in WA” it was difficult to ascertain whether there would be a full blown plague. But he said the signs were very concerning. Mr Elliot-Lockhart said with ample food and shelter from crops, good water sources, and with coming into spring, numbers are expected to increase. Mice start breeding at the start of spring when just six weeks old, and litters of six to 10 pups are born every 19 to 21 days. “There’s no reason for numbers to crash. They’re already getting stuck into lupin and canola crops. Over summer they get in to houses and sheds and start chewing on machinery and wires, they can be quite destructive,” Mr Elliot-Lockhart said. He hopes the outbreak won’t be as bad as last summer’s unrelenting plague on the east coast which destroyed crops, stock feed and equipment, causing hundreds of millions of dollars in damage and triggering major mental health issues. “We haven’t got the numbers that were seen over in the east yet, but if we aren’t proactive about it, things could get fairly ugly,” Mr Elliot-Lockhart said. “I don’t think we’ll get to those levels, but if we get a wet summer it’s entirely possible.” Mr Elliot-Lockhart said in the Mid West, farmers were scrambling to bait paddocks to reduce the pace at which mice will increase, and estimated tens of thousands of hectares would have been aerial baited in recent weeks. But wet weather had slowed efforts, which have also been constrained by a lack of available planes and pilots. “Supply of bait is tight and what is coming in is virtually going straight out,” he said. When questioned whether the mice would reach Perth, CSIRO’s Mr Henry said mice were always present in towns and cities in small numbers. The same favourable conditions that encouraged breeding in rural areas would inevitably lead to high numbers in Perth. “There isn’t enough food in Perth to support a really high population. You won’t see a plague in Perth, but there will likely be more mice than usual,” he said.