Barn owls are especially vulnerable to rodenticide poisoning because they accumulate toxins from eating poisoned rodents, causing internal hemorrhaging and death in one of the most widespread and preventable forms of wildlife poisoning.
Rodenticide poisoning in barn owls represents a welfare harm that cascades through the food chain from rodents to the predators that eat them. An owl dying from anticoagulant poisoning suffers through days of progressive internal bleeding before death or rescue. The tragedy is compounded by the fact that barn owls provide effective, natural rodent control that makes chemical rodenticides unnecessary in many agricultural settings. Providing nest boxes and maintaining rough grassland habitat supports owl populations that control rodents more sustainably and without the welfare cost of secondary poisoning. This is a case where the welfare solution is also the more ecologically sound management approach.