Mouse activity at seeding: what to check and what to do

By Simon Kruger, WMG Project Communications Officer

Mouse activity across WA’s grain growing regions is at levels that warrant attention heading into seeding. CSIRO rodent researcher Steve Henry has described numbers in parts of WA as being at plague proportions, with burrow counts north of Geraldton reported as high as 40 per 100 square metres in some areas. For context, two to three burrows per 100 square metres would normally be cause for concern.

The conditions driving this are straightforward. A record 2025 WA harvest left an abundance of food available in paddocks through summer and autumn, providing ideal conditions for mouse breeding. Mice begin breeding at six weeks of age and produce litters of six to ten pups every 19 to 21 days. Numbers can build rapidly and populations are not uniform across a district, meaning local monitoring matters more than regional averages.

The West Midlands region sits within the broader northern agricultural region where elevated activity has been reported. Do not assume your paddocks are clear without checking.

How to monitor

Walk a 100-metre transect across the paddock and count active burrows in a one-metre-wide strip. This gives you an assessment area of 100 square metres. Vehicle inspections are not reliable, as standing stubble can hide burrow activity that is only visible at ground level.

Mouse chew cards are a useful complementary tool and can be ordered from GRDC at no cost by calling 1800 110 044 or emailing ground-cover-direct@canprint.com.au.

Log your observations, whether mice are present or absent, through the MouseAlert tool at feralscan.org.au/mousealert. This data supports the CSIRO monitoring program and helps build a more accurate regional picture of activity.

What to do if numbers are high

If mice are present at or around sowing time, baiting at or as soon as possible after seeding is recommended to prevent damage to freshly sown crop. Contact your bait supplier early. In seasons where activity is elevated across multiple regions simultaneously, demand for bait can rise quickly and supply can tighten. Discuss options with your agronomist or supplier and use any product strictly in accordance with the label.