Effective control of rodents is an essential part of farming and food hygiene, as rats and mice can spread human and animal disease, contaminate food stuffs and cause damage to property.

Rat poisons, also known as rodenticides, are the most common means of achieving rodent control.

Ireland's Agriculture and Food Development Authority (Teagasc) is encouraging responsible rodenticide use to minimise effects on wildlife.

Rodent predators can be exposed to rodenticides by feeding on rodents that have died as a result of poisoning, or by catching and feeding on live rodents which have these toxins in their systems.

Catherine Keena, Teagasc Countryside Management Specialist said; “Recent studies, in Ireland, have shown that Barn Owls and Red Kites have evidence of rodenticides in their bodies, likely acquired through consumption of prey.

"The contamination of such species has been confirmed through post-mortem examination of carcases collected as part of ongoing statutory monitoring and is a matter of serious concern.”

The largest type of land-use in Ireland is farmland. The methods of managing farmland impact on our wildlife and wildlife habitats. Healthy environments have a rich variety of habitats that support and maintain biodiversity.

The presence of predators which are at the top of the food chain indicates a healthy ecosystem. Predators play an essential role in maintaining biodiversity and balance in nature. Birds of prey and owls are top predators, as are mammals such as Pine Marten and Stoat.

Rats and mice form a major part of the diet of these predatory species. Barn owls, long-eared owls, red kites, kestrel and buzzards are some of the species of birds of prey and owls that can be exposed to rodenticides by feeding on rodents that have been poisoned.

A Campaign for Responsible Rodenticide Use (CRRU) aims to protect wildlife while promoting and providing effective rodent control through the responsible use of rodenticides in rural areas.

CRRU Ireland was formed by companies that manufacture and distribute rodenticides in Ireland. CRRU advocates the responsible use of rodenticides to control rodent pest species in the interest of protecting human and animal health and avoiding contamination of food.

Its prime objective is to minimise negative impacts on wildlife. CRRU has drawn up a CRRU Code to minimise risks arising for wildlife.

The responsible use of rodenticides requires implementation of an Integrated Pest Management (IPM) approach to rodent pest control together with adherence to the CRRU Code, an approach essential for effective long term management of rodents.

Rodent control, either by the use of traps, biological means (cats or dogs) or rodenticide bait, will not prove effective unless other measures are also taken.

Important measures in an integrated approach are:

• Rodent proofing, to deny rodents access to sensitive areas;
• Habitat modification, to deny rodents food, water & shelter;
• and Rodent killing, to remove rodents in existing infestations.

GLAS, the new Irish Agri-Environment Scheme, specifies that participants should comply with the CRRU Code in their daily farming activities.

Teagasc recommends that farmers follow the CRRU Code to ensure that the threat of secondary exposure to wildlife associated with rodent control measures is minimised. Information on the Campaign for Responsible Rodenticide Use has been sent to all Teagasc clients.

Further Reading

Read our article on resistant 'super rats' by clicking here.