Non‐invasive method for monitoring the exposure of Barn owls to second‐generation rodenticides

Abstract

Abstract Chemical analysis of rodenticide residues in regurgitated owl pellets has been shown to be a sensitive, non‐invasive method for monitoring the potential exposure of Barn Owls to second‐generation rodenticides in their prey. The method, originally developed for flocoumafen, has been extended to two other rodenticides. brodifacoum and difenacoum. The method was validated as part of a toxicity study in which Barn Owls were separately fed 40–130 μg day −1 of brodifacoum, difenacoum and flocoumafen in mice over 15 days. Each day an average of 25% of the consumed rodenticide was regurgitated in the pellets.