Barn owls accumulate rodenticides from eating poisoned prey, causing internal bleeding, neurological damage, and death, with welfare impacts felt most severely where rat control relies on second-generation rodenticides.
Barn owls suffering rodenticide poisoning experience welfare compromise from sublethal and lethal poisoning at different severities. Sublethal accumulation impairs clotting function, causing internal hemorrhage and anemia that reduces hunting performance and physical condition. Neurological effects of some rodenticides cause incoordination and impaired hunting, causing starvation. At lethal doses, uncontrolled bleeding from internal hemorrhage causes a painful death that may be prolonged over days. The secondary nature of the poisoning means barn owls die from controlling pests that farmers also wish to eliminate, creating a situation where wildlife welfare and agricultural goals are in direct conflict.