UK barn owl populations have recovered through nest box provision but face a new threat from second-generation anticoagulant rodenticides that accumulate in their prey and cause slow internal bleeding.
Barn owl rodenticide poisoning causes prolonged suffering. Animals with sublethal poisoning experience weakness, impaired flight, and haemorrhage. They may survive for days in a deteriorating state before dying. The invisible nature of the threat - owls consuming poisoned prey without any direct human intent - makes prevention challenging. Barn owls that raise chicks in nest boxes only to die from accumulated rodenticide represent a particularly stark welfare failure. Transitioning farm rodent control from second-generation rodenticides to first-generation alternatives or physical trapping removes this welfare harm.