Exposure of Raptors and Waterbirds to Anticoagulant Rodenticides (Difenacoum, Bromadiolone, Coumatetralyl, Coumafen, Brodifacoum): Epidemiological Survey in Loire Atlantique (France)

Abstract

Anticoagulant rodenticides are commonly used to control rodent pests all over the world. These pesticides inhibit the vitamin K cycle in the liver, prevent blood clotting and cause death by hemorrhage. Despite the fact that they were intended for the control of commensal rodents, they may affect non target species, either directly by consumption of contaminated cereal-based baits, or indirectly by consumption of contaminated preys (secondary poisoning). Secondary poisoning of non target species by anticoagulant rodenticides has been confirmed in many mammals and birds species, such as mustelids, foxes and birds of prey (Shore et al., 1996; Berny et al., 1997; Birks 1998; Stone et al., 1999; Stone et al., 2003; Harding 2004; Fournier-Chambrillon et al., 2004). Nevertheless, poisoning of non target species by direct consumption of anticoagulant rodenticides in the form of contaminated baits is poorly documented. Loire Atlantique is a French department well known for its wetlands and marshes in which anticoagulant rodenticides are commonly used especially against coypus (Myocastor coypus) because of the damage to cereal fields, rivers and water ponds banks. The aim of this study was to estimate the exposure of raptors and waterbirds to anticoagulant rodenticides in Loire Atlantique.