Barn Owls and Rodenticides: Secondary Poisoning Crisis

Secondary rodenticide poisoning kills thousands of barn owls annually when they consume rodents contaminated with anticoagulant rodenticides, causing prolonged internal bleeding deaths.

Key Facts

Over 95 percent of barn owls tested in the UK have rodenticide residues in their livers
Second-generation anticoagulants including bromadiolone cause prolonged deaths over several days
Barn owl populations have declined 70 percent in parts of Europe over the past 50 years
Alternative rodent control including traps and first-generation rodenticides reduces secondary poisoning risk
Wildlife-friendly pest control guidance is available from conservation organizations for farmers
Regulatory restrictions on second-generation rodenticide amateur use have been implemented in several countries

Welfare Considerations

Secondary rodenticide poisoning causes one of the most prolonged and distressing deaths in wildlife. Anticoagulant rodenticides prevent blood clotting; affected owls die over several days from internal hemorrhage and progressive weakness. The scale of contamination indicates secondary poisoning is a routine outcome of widespread rodenticide use rather than exceptional. The owls that die are predictable casualties of a pest control method that concentrates toxic compounds in the prey items barn owls depend on. Switching to lower-risk alternatives addresses this welfare harm directly.

What You Can Do

Avoid second-generation anticoagulant rodenticides for rodent control around farm buildings and homes
Use traps, proofing, and habitat management as first-line rodent control approaches
Advocate for stricter regulation of second-generation anticoagulants to protect raptors
Support barn owl conservation programs that monitor populations and promote wildlife-friendly pest control