Second-generation anticoagulant rodenticides accumulate through the food chain and are poisoning barn owls and other raptors across the Northern Hemisphere.
Barn owls dying from rodenticide poisoning experience internal haemorrhage — a painful, prolonged death. They may be found weak and grounded, unable to fly, days before death. The route of exposure is through consuming rodents that have themselves consumed poison but not yet died — a secondary exposure that concentrates toxins through the food chain. The irony is profound: farmers use rodenticides to protect grain, while poisoning the owls that would naturally control rodent populations without chemical inputs. Integrated pest management that includes owl box provision and reduced reliance on second-generation rodenticides achieves rodent control while protecting raptors.