Barn owls are extensively contaminated with second-generation anticoagulant rodenticides, causing sublethal welfare effects and contributing to mortality across the UK population.
Sublethal SGAR poisoning causes prolonged suffering: owls with internal haemorrhaging experience blood loss into body cavities, impaired vision, and weakness that compromises hunting ability and survival. Birds found dead with SGAR residues may have experienced extended periods of debilitation before death. The near-universal contamination of UK barn owls with these compounds represents a systemic welfare failure in how rodenticides are regulated and used. Stewardship requirements for professional use have been tightened, but domestic and agricultural use continues to expose barn owls. Transitioning to effective rodent management that does not rely on SGARs is a welfare priority.