It has been estimated that total crop losses caused by rodents each year could feed 200m people.

However, it is important that all wildlife is protected while controlling rodents, Éanna Ní Lamhna told a Teagasc Signpost webinar on Friday 18 August.

Ní Lamhna is communications officer with the Campaign for the Responsible Rodenticide Use (CRUU), which supports best practice and responsible rodent control in order to protect wildlife from rodenticide (rat bait) exposure.

"Rats and mice cause serious economic loss and there's different ways by which this happens.

"They consume food, they contaminate food and they spoil food and feed. They also cause damage to machinery, cause losses of poultry and game birds and cause loss of quality assurance," Ní Lamhna told Friday morning's Signpost webinar.

Predators

Ní Lamhna reminded farmers of the importance of barn owls on their farm to control rodents.

"One of the typical natural predators that we know comes out at night and feeds on mice and rats are the barn owls.

"They reckon a pair of barn owls feeding a nest of young will catch 500 rats in a feeding season. So that's very efficient if you can have a pair of barn owls on your farm," she said.

However, there have been cases of lethal exposure of rodenticides found in a wide range of wildlife species recorded in studies by the National Parks and Wildlife Service, the Heritage Council and the Department of Agriculture, Ní Lamhna added.

Among the species that have died as a result of rodenticide poisoning include barn owls, red kites, kestrels and buzzards.

Research was carried out, according to Ní Lamhna, where 85% of barn owl carcases carried low-level residues of rodenticides.

Ireland was also found to have three-times higher residue levels than those found in the UK.

Ní Lamhna stressed that many species of wildlife are already under threat of extinction, adding: "We don't need to be adding to it by careless and necessary use of rodenticides."