toxicity of three second-generation rodenticides to barn owls

The toxicity of three second-generation rodenticides to Barn Owls (Tyto alba Scop.) has been investigated. Brodifacoum, difenacoum and flocoumafen were separately fed to owls over a period of 15 days via rodenticide-fed mice to simulate the potential route of exposure in the wild. The owls survived a cumulative dose of each rodenticide of at least 1.9 mg kg-1 owl body weight over 15 days. This is equivalent to the consumption of two 25 g mice with a rodenticide residue of 1 mg kg-1 each day for 15 days. Residue analysis confirmed that the liver is the organ which retains the largest residue of ingested rodenticide.