Anticoagulant rodenticides used to control rats and mice accumulate through food chains, poisoning raptors, mustelids, and foxes with significant welfare consequences.
Anticoagulant rodenticide poisoning causes a prolonged, painful death characterised by internal haemorrhage. For rodents exposed directly, this welfare cost is the mechanism of action. For raptors, mustelids, and foxes that accumulate sublethal concentrations through predation of poisoned rodents, the welfare consequences range from neurological impairment that compromises hunting ability to acute haemorrhagic disease and death. The scale of non-target wildlife contamination documented in UK and European surveys is substantial, affecting protected species including barn owls and red kites at population-significant levels. Alternative rodent control methods — exclusion, habitat management, population management, first-generation rodenticides with lower secondary poisoning risk — exist for many situations where second-generation anticoagulants are currently used without adequate justification.