A leading mouse expert has moved to reassure people in Sydney the plague affecting parts of rural New South Wales is not spreading to the city – despite increased sightings recorded on a tracking map.
In recent days, residents in Cabramatta, St Clair and Revesby in Sydney have reported “medium” mouse activity with some posting photos of destroyed documents and mouse faeces.
The residents were users of an online platform called Mouse Alert which allows people to register rodent infestations.
The map currently displays hundreds of red dots across parts of regional Queensland, NSW and Victoria.
Increased reports in Sydney had raised concerns the mouse plague terrorising regional NSW was marching into the capital.
But the CSIRO says the increased mouse sightings is nothing unusual.
CSIRO researcher and mouse expert Steve Henry said people shouldn’t be afraid and it was almost impossible the regional mice would invade the city.
“Mice are not moving across the landscape in a wave,” he said.
“They only weigh 13 grams and they have tiny little legs. Moving is a really dangerous thing for a mouse to do because it puts itself at risk of predation. They’re only going to move if they run out of food, and they’re only going to have limited movements, until they encounter the next lot of food.”
Henry said suggestions the mice could arrive in Sydney by August was “nonsense”.
It was normal to see higher numbers of mice in the city because conditions had been good, the research officer said.
“There might be more mice in Sydney than usual at the moment because conditions have been favourable for the mice that are already there to breed slightly higher numbers.
“But there are not nearly enough food and resources within that system for mice to get to the numbers they’re at in the bush. There might be a few more mice in Sydney than normal and you might have four, five, or six in your house at once, but you’re not going to be taking 30, 40 or 50 mice out of your house the way people in the bush are.”
Millions of mice have ransacked farms across large swathes of eastern Australia – eating crops and damaging property.
They’ve overrun towns, with people finding them all over their homes, in their furniture, ceilings, bins, classrooms and even in hospitals.
The NSW government has approved emergency measures to allow the use of the world’s deadliest mouse poison but Henry says there is no indication when the plague may end. “They’re just breeding up, declining, then breeding up again.”
He said when the plague did conclude it would come suddenly and ferociously.
“When outbreaks end, traditionally they end very suddenly,” Henry said.
“They crash away really quickly, disease moves through the population and they start eating each other and then before you know it, they’ve just died out. They become sick and stressed and their population just crashes away to nothing.
“But we can’t predict when that can happen. Because it happens so quickly it’s hard to study.”
It’s a situation that has prompted some farmers to feel helpless, according to Brett Hosking, the chair of Grain Growers.
“Parts of the state are still inundated, and I think they’re feeling very frustrated. I’d imagine for some, there’s a sense of helplessness as they try and get on top of it.
“It’s still fairly consistently bad, there are some areas where growers have been able to get on top of it, which is good, but even in those situations, one pair of mice can turn into 30 or 40 mice within a matter of weeks.”
Hosking described what felt like a losing battle for farmers – but insisted they had maintained a positive outlook.
“Every farmer is an eternal optimist. They take it in their stride, but to a point,” he said. “It does start to get on top of you, and optimism does start to drop a little bit. But in the most part, growers see it as part of the job that needs to be done.”