The nightmare mouse plague of 2021 will go down in the history books and has left many terrified of the return of rodents.
Experts continue to closely monitor mouse numbers across regional Australia and are urging residents, especially farmers, to learn from the last plague by acting now to stop numbers exploding again.
"People were pretty badly affected by mice, not just financially but also psychologically," CSIRO research officer Steve Henry said.
"The fear they might come back is very real."
Diligent baiting programs and months of rain and inundation finally brought mouse numbers under control.
However, with an abundance of feed and a huge harvest expected this year, it was critical farmers knew the signs and acted quickly if mice started to breed in large numbers again.
Current mouse numbers stable
Mice were a routine part of life on the land so sightings were common, and experts currently weren't receiving reports of mice in concerning numbers.
However, winter was typically a time when breeding slows and the critters hibernated.
"At the moment, things are fairly quiet through a large chunk of central and northern New South Wales," Mr Henry said.
"We were getting some reports earlier in the season as people were finishing up harvesting their summer crops that there was some mouse activity where there was lots of food available.
"Through other parts of the Central West, we're hearing reports of mice coming into houses and sheds. That's something that happens pretty regularly at this time of the year as the weather gets colder.
"There might be a few more around, a little bit of carryover population [from the plague].
"But we're not expecting those populations to increase now through the winter time because they will stop breeding."
Farmers urged to be vigilant
Farmers were being warned to ensure there was less food and shelter, particularly post-harvest when the last mouse plague really kicked off with an abundance of grain left after stripping crops.
The concern was this food source helped mice to survive and breed in huge numbers during the warmer months.
"It's really important. It's a matter of ongoing vigilance. There was a significant gap, about 10 years, between mouse plagues in New South Wales.
This year had been exceptionally wet for regional NSW, leading to issues with sowing winter crops, but a huge harvest was still anticipated.
"As we get to the end of winter and the start of spring, because crops are worth so much this year and because there's a fair chunk of the winter program that hasn't been able to be put in, there'll be a real focus on summer cropping," Mr Henry said.
"That means we need to make sure that we understand what's happening with mass populations at the start of spring.
"If we do start to see that increase, be prepared to take some action to push those numbers down early in the season to take some of the breeding potential out of the population."
Lessons from the mouse plague
The horrors of the mouse plague were far from forgotten, and researchers and landholders were still learning about mouse activity.
"We always learn from these things, but what it's helped us to do is focus our attention on some of the really important questions," Mr Henry said.
"Some of the things that came out of it were the understanding of the social and economic impact of mass plagues, the role pasture plays as a refuge habitat, but also understanding disease profiles and understanding the implications for feeding potentially-contaminated fodder to livestock."
The impact of mouse plagues on human health was also a concern.
"We learnt about the implications of diseases that are transmitted from mice to humans," he said.
"They're all part of a suite of projects we're undertaking in New South Wales now to try get us better prepared for the next outbreak."
Research into solutions
Following the severity of last year's plague there had been significant NSW government investment in research for short and long-term solutions.
"We're starting some research associated with understanding mice and pastures and whether those pastures are playing a role as a refuge habitat for mice," Mr Henry said.
"It's a location where they can hang out when things aren't favourable in the crops and then re-invade crops when conditions do get favourable.
"We also are starting to get a better understanding about some of those drivers for outbreaks, and continuing to make farmers aware of what's happening in their paddocks so that we can be on the front foot as numbers start to increase."
