Barn owls that hunt rodents in agricultural areas frequently accumulate lethal or sublethal doses of second-generation anticoagulant rodenticides, threatening both individuals and populations.
Anticoagulant poisoning causes prolonged internal bleeding and organ damage. Affected owls may suffer for days before death, experiencing weakness, disorientation, and inability to hunt. The welfare cost is compounded by the fact that these birds are killed while performing a service beneficial to farmers.