Rodenticide 'alarm bells' after barn owls show residues

New surveillance in barn owls as well as intelligence from the government-run Wildlife Incident Investigation Scheme has 'rang alarm bells' for professional-grade rodenticide users.

Two-thirds of the latest sample of barn owls has shown residues from products containing the rodenticide brodifacoum, an active ingredient in many brands, the Campaign for Responsible Rodenticide Use (CRRU) has said.

The body emphasised that this alert was being issued to farmers in parallel with gamekeepers and pest control technicians "on a no blame basis".

CRRU chairman Dr Alan Buckle said everyone using rodenticides in rural areas 'shares responsibility' to prevent access by non-target wildlife, for which barn owls are the government-designated benchmark.

“No such products are licensed for use in ‘open areas’ where the main food sources for barn owls, field mice and voles, are often found," Dr Buckle explained.

“It’s highly likely that brodifacoum-contaminated field mice and voles eaten by owls have acquired residues from rodenticide products placed illegally in open areas."

On all rodenticide product labels, manufacturers have to include specific instructions required by the government regulator, the Health and Safety Executive (HSE).

Failing to follow these, whether deliberate or unintended, is illegal and risks prosecution.

Dr Buckle added: “Equally concerning is a sudden and marked increase in the numbers of wildlife incidents involving brodifacoum.

"At least some of these involve either negligent misuse or intentional abuse to harm wildlife.”

CRRU said gamekeepers, pest control technicians and farmers must remember the legally binding ‘Directions For Use’ printed on every rodenticide product label.

They cover allowed outdoor uses, either around buildings, in open countryside or in rodent burrows.

In all cases, product label instructions about protecting bait placements from non-target species must be followed, the CRRU said.