Wildlife

Rodenticide Poisoning of Wildlife: Secondary Toxicity

Anticoagulant rodenticides used to control rats and mice cause secondary poisoning in predators including owls, red kites, and hedgehogs, causing slow, painful deaths.

Key Facts

Over 95% of barn owls tested in the UK carry anticoagulant rodenticide residues
Red kites, buzzards, and polecats are frequently affected by secondary poisoning
Second-generation anticoagulant rodenticides persist in the food chain for weeks
Animals poisoned by rodenticides die slowly from internal bleeding over days
Non-rodent wildlife including hedgehogs can be directly poisoned by bait stations

Welfare Considerations

Secondary poisoning from anticoagulant rodenticides causes a prolonged death from haemorrhage. Affected predators lose coordination, become lethargic, and haemorrhage internally over days. Barn owls, which eat many poisoned rodents in a season, accumulate sub-lethal doses that impair immune function and reproduction even without causing death. The welfare cost to predator populations is substantial and largely invisible without post-mortem screening.

What You Can Do

Use non-anticoagulant rodent control methods where possible including traps and proofing
Follow label guidance to place bait where non-target wildlife cannot access it
Report suspected raptor or hedgehog poisoning to Wildlife Incident Investigation Scheme
Support RSPB and CJ Wildlife campaigns on rodenticide reform
Advocate for stronger restrictions on second-generation anticoagulant rodenticides