Barn Owls and Rodenticide Poisoning

Barn owl populations are significantly harmed by secondary poisoning from rodenticides used on farms and in buildings, accumulating in prey species and causing death and reproductive failure.

Key Facts

Second-generation anticoagulant rodenticides are found in the majority of barn owls tested post-mortem in the UK
Barn owls eat primarily small mammals that accumulate rodenticide residues before being caught
Poisoning causes internal bleeding that may take days and is a welfare concern for individual birds
Rodenticide-free pest management using grain protection and natural predator support is available
The Campaign for Responsible Rodenticide Use has developed stewardship frameworks to reduce off-target exposure

Welfare Considerations

Secondary poisoning by rodenticides is one of the most insidious welfare threats facing barn owls. The owl does not encounter the poison directly; it eats voles and wood mice that have fed on bait or eaten poisoned rodents, accumulating sublethal doses that eventually cause anticoagulant haemorrhage. Birds may die slowly over several days from internal bleeding. Population-level effects include reduced breeding success as reproductive physiology is disrupted. The availability of effective rodent control without rodenticides — through grain protection, proofing buildings, and encouraging natural predators — means this welfare harm is largely preventable.

What You Can Do

Avoid using second-generation anticoagulant rodenticides in buildings and farms
Explore integrated pest management alternatives that do not rely on rodenticide bait
Install barn owl nest boxes to support local populations
Report dead barn owls to surveillance programmes that monitor rodenticide exposure
Advocate for stricter regulations on rodenticide use near wildlife habitats