Barn owls are among the raptors most severely affected by secondary rodenticide poisoning, with studies showing high rates of exposure in wild populations across Europe and North America.
Barn owl rodenticide poisoning represents a predictable and preventable welfare problem at significant scale. These charismatic and ecologically important birds are exposed to rodenticides through the very prey they are adapted to hunt, meaning that the pest control activity designed to reduce rodent pressure in farm buildings is simultaneously poisoning the predators that provide natural rodent control. Welfare impacts range from death — which post-mortem studies suggest rodenticides contribute to — to sub-lethal impairment affecting reproductive success and survival. The solution requires both regulatory tightening of rodenticide access and use requirements, and farmer education about the irony of poisoning the predators that provide the service they are trying to buy chemically. Providing barn owl nest boxes and maintaining rough grassland habitat supplements natural rodent control.