U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

January 2007


Published in Proceedings of the 12th Wildlife Damage Management Conference (D.L. Nolte, W.M. Arjo, D.H. Stalman, Eds). 2007.


Non-native rats (Rattus spp.) and mice have been introduced to more than 80% of the island groups around the world. They have caused ecosystem-wide impacts, including the extirpation and extinction of many native and endemic species which evolved in a mammalian predator-free environment. Fortunately, practitioners have developed techniques to eradicate introduced rodents, allowing ecosystems to recover. Rodenticides have proven an effective tool in eradications, having been used in over 300 successful eradications worldwide. Careful planning, adequate resources, and a sustained effort by competent field staff are needed to help ensure a successful eradication program. Island eradications are logistically complex and often quite expensive, requiring that once initiated, removal of 100% of rodents is paramount to facilitate support for future projects. However, efforts must be made to reduce potential rodenticide impacts to non-target animals, especially native birds and mammals. Standard considerations include confirming the species present, their behavioral characteristics and scale of risk, the legal status of species present, and population levels and distributions. To minimize risks, the type of rodenticide used, bait formulation, placement (stations or broadcast), timing of application, number of applications, and weather needs to be considered. It is important to recognize the great value of a successful invasive rodent eradication to island resources; recovery of native flora and fauna is usually rapid and remarkable.