Increasing mouse numbers a cause for concern

increased mouse activity with reports of increasing damage to crops and fodder across the state.

Two years after a mouse plague saw vehicles, buildings and towns infested while crops were destroyed, NSW Farmers president Xavier Martin is urging growers to be extra-vigilant about mouse activity.

“Members are telling me they’re seeing mice again all the way from Queensland down to the Victorian border and out west towards Adelaide,” Mr Martin said.

“We need everyone to keep an eye out for mice, in particular use their chew cards, and report any activity to authorities.

“It’s important to stay on top of this issue so we can avoid a repeat of the 2021 mouse plague, so please if you see something, say something.”

In 2021 the rodents swarmed rural and regional communities, chewing their way through hundreds of millions of dollars’ worth of crops, damaging farm machinery, vehicles and buildings in the process.

People reported being “sickened” by the sight of ‘carpets’ of mice on highways.

Farmers and rural landholders are urged to report mouse activity by visiting Feral Scan online and can download a chew card template from GRDC.

Online information from GRDC says growers should monitor paddocks to get an accurate idea of their mouse problem as numbers can vary significantly within a district.

Monitor by walking a transect of 100 metres across the crop and counting active holes in a 1-metre-wide strip (gives an area assessed of 100 square metres).

Pull back stubble to check closely for mouse activity. Repeat several times across the paddock.

Active holes can be identified by sprinkling talcum powder or corn flour around holes and inspecting the level of disturbance the following morning.

One burrow per 100 square metres equals 100 burrows per hectare, or 200 mice per hectare. Burrows usually contain 1 to 4 mice but can have up to 40 mice.

Checks should be made across a paddock as populations can be patchy.

Hole counts vary by soil type. In cracking soils, holes may be difficult to identify. In sandy soils, mice may dig many holes in search of seed, which can look similar to nesting burrows. In hard-setting soils, there may be few holes, but each can contain many mice – up to 40 per hole during plagues.

Mouse chew cards are most reliable for gauging numbers in late autumn/winter when food is scarce.

They are less reliable as crops mature because the crop provides a more attractive food source than the oil-soaked card.