Join us for national archaeoloGY week 2023 Thursday 25th of May 2023 5:30-7:30pm >> Get your tickets here

The Mouse Plague and the Impending Snake Boom

Farmers across New South Wales are dealing with the largest mouse plague they have ever seen and all these mice make an excellent smorgasbord for snakes. When will this end and how to deal with the situation.
Brown mouse next to green plants.

Share This Post

The mouse, a tiny beast known to incite fear in many, in fact, some people are so scared of mice there is even a phobia to describe it, called Musophobia. It comes as no surprise as mice are known for their terrible traits of being waste producers, parasite, and disease carriers; they may be small, but their impact can be mighty. But what is worse than a single mighty mouse? A plague of mice! (Sorry Musophobics). Farmers across New South Wales are dealing with the largest mouse plague they have ever seen. As if our farmers hadn’t been dealing with enough already, first came the drought, then the fires, now waves of mice scurry across their fields, desecrating grain-growing country resulting in losses of up to 100%.

When will this end?!

Over the last 120 years, plagues of mice have been recorded in Australia in the winter cropping regions after high rainfall events, causing economic chaos. So, it appears that this plague may have been a little more predictable than we thought, according to CSIRO research officer Steve Henry. Researchers do not know exactly when this plague will end, but it is likely to happen abruptly after food resources deplete, based on previous mouse plagues. Population regulation is a natural phenomenon, based on food, shelter and social requirements. As the population of mice increases, these key factors are limited, and resources become scarce causing the population growth rate to crash. Mouse phobics rejoice, this too shall end!

Researchers do not know exactly when this plague will end, but it is likely to happen abruptly after food resources deplete, based on previous mouse plagues.

An app worth downloading

In response the economic, social and environmental damages a mouse plague brings, a free app was developed in 2014 called MouseAlert for farmers to detect changes in mouse activity to assist in predicting and preparing for plagues, and assistance with planned coordinated control activities. A stronger uptake of app users will assist in better predictions and management for when to begin controls before farmers plant crops. CSIRO expert Steve Henry is recommending that farmers monitor mice closely over winter and to bait early in the Spring before sowing crops.

Farmer in fields possibly making use of the MouseAlert App to detect changes in mouse activity in the area

Non-target poisoning

Not only are people suffering from this plague, the beloved owl and other birds of prey that rely on mice as a key food source are being secondarily poisoned from anticoagulant rodenticides (SGARs, also known as second generation). If you choose poison as a measure of control during the plague, recommendations to protect wildlife are to leave the SGARs on the shelf and look for FGARs (known as first generation, “Active Constitutes” or compounds: Warfarin and Coumatetralyl) as they break down faster and reduce the chance of larger animals being poisoned too.

Local farmers in Timbumburi have reported unknowingly purchasing second generation baits (brodifacoum, bromadiolone and difenacoum) off the shelf in supermarkets and loosing companion animals to secondary poisoning from eating as little as one mouse. Rodenticides like bromethalin, is a non-anticoagulant neurotoxin that causes seizures, paralysis and death, and there is no antidote so be mindful of your pets if purchasing this poison. The farmer has also reported “paddocks full of dead birds”, including hawks, owls, magpies, and currawongs, stating that the baits “will be an ecological disaster” and choosing alternative options to protect the natural mice predators.

Trust me, we need these birds of prey to stick around to continue their natural predatory control all year round, and the owls, eagles, falcons, kookaburras, magpies, ravens, and currawongs will thank you for it!

Fun fact: Mice reach sexual maturity at 6-8 weeks of age, and single female mouse can have up to 15 litters a year, with up to 12 pups. That’s up to 180 pups for a single mouse per year!

The snake boom

Now, I think it is safe to say that no one is a fan of sharing their home with the mice, but I think we can all agree that venomous snakes are not the kind of house mate you were hoping for either. All these mice make an excellent smorgasbord for snakes, meaning, bigger, fatter, snakes booming in numbers. Before you start panicking and imagining a “Snakes on a Plane” or “Anaconda” situation before your eyes, even with the increased numbers, you are far less likely to stumble across a snake than a mouse. The previous drought increased snake mortality rates near to the point of extinction for some species, and their numbers are expected to sliver back up with the higher prey availability.

Warning sign snakes, greenery in background.

Stay away

Contrary to popular belief, snakes are not naturally aggressive, and most bites occur if they have been provoked or hurt by humans. In Tamworth, the infamous venomous Brown Snake, which can be lethal to humans (and known to feast on rodents) is likely to be in higher numbers next spring. If you have a snake in your home, the best thing to do is grab the kids and pets and stay away, call your local snake handler or wildlife group. They are the experts and will know exactly what to do and how to not get bitten.

To find out more on how to keep snakes away from your home visit:


Arundale, V. (2021). Mouse plague: UNE Zoologist Dr Karl Vernes Says No One Can Predict When it Will End, but It Will. Parks Champion-Post, Retrieved from:

Birdlife Australia. (2021). Bird-friendly Rodent Control. Western Australia, Floreat, Retrieved from:

Britannica, The Editors of Encyclopedia. (2019). “Carrying capacity”. Encyclopedia Britannica,

Brown, P. R., Huth, N. I., Banks, P. B., & Singleton, G. R. (2007). Relationship between abundance of rodents and damage to agricultural crops. Elsevier, 120(2-4), 405-415. Retrieved from:

Findlay, M. (2021). Mouse Plague, Environmental Improvement Leads Snakes to Thrive in Central West. The Land, Retrieved from:

Grains Research & Development Corporation. (2021). Tips & Tactics, Better Mouse Management. Barton, ACT, Retrieved from:

Hogan, H., & Thackray, L. (2021). Worsening NSW Mouse Plague Now an ‘Economic and Public Health Crisis’. ABC, Rural, Retrieved from:

NSW Government. (2019). Snakes. Retrieved from:

Pech, R., Brown, P., Cruz, J., Henry, S., Hinds, L., Byrom, A., West, P., & Farrel, J. (2015). Surveillance and Forecasts for Mouse Outbreaks in Australian Cropping Systems. Invasive Animals Cooperative Research Centre, 1-34. Retrieved from:

Quesenberry, K. E., & Donnelly, T. M. (2020). Breeding and Reproduction of Mice. MSD Manual Veterinary Manual, Retrieved from:

Reading, C., & Jofre, G. (2020). Smooth Snake Population Decline and its Link with Prey Availability. Amphibia-Reptilia, 41(1), 43-48. Retrieved from:

Ruscoe, W. A., Brown, P. R., Henry, S., Van De Weyer, N., Robinson, F., Hinds, L. A., & Singleton, G. R. (2021). Conservation Agriculture Practices Have Changed Habitat Use by Rodent Pests: Implications for Management of Feral House Mice. Journal of Pest Science, 1(1), 1-11. Retrieved from:

Vessy, S. H. (1987). Long-term Population Trends in White-Footed Mice and the Impact of Supplemental Food and Shelter. American Zoologist, 27(3), 879-890. Retrieved from:

Wakatama, G., & Johnson, K. (2021). Mouse Plague Wreaks Havoc Across Parts of NSW, Farmers Fear for Crops. ABC, Newcastle, Retrieved from:

About The Author

Stay In The Loop

Stay up to date with blog articles, industry news, updates to legislation, global and local developments in conservation as well as exciting news and updates from the Moss Environmental team.

Work with us

Moss Environmental can help you meet your regulatory requirements while ensuring that your projects are environmentally sound.

More From The Moss Environmental Blog

Moss Environmental Pty Ltd Announces Merger with OzEnvironmental
Moss Environmental Pty Ltd Announces Merger with OzEnvironmental

[Tamworth, NSW, 19th July 2023] Shonelle Gleeson-Willey the Director of Moss Environmental Pty Ltd is delighted to announce it has merged with OzEnvironmental Pty Ltd,

Read More