Wild pigs in the Monterey County area were exposed to pesticide bait containing the anticoagulant rodenticide diphacinone, according to findings by the California Department of Fish and Wildlife’s (CDFW) Wildlife Health Lab (WHL) and the California Animal Health and Food Safety Laboratory in Davis.
In March, a wildlife trapper reported multiple observations of blue muscle or fat found in wild pigs. The blue tissue can be a sign of rodenticide bait ingestion. CDFW’s WHL investigated, finding the anticoagulant rodenticide diphacinone in the stomach and liver contents of one of the wild pigs that was recovered with blue tissues.
Wildlife can be inadvertently exposed to rodenticides either by eating rodenticide bait or by eating other animals that have ingested rodenticides. Rodenticide baits often contain dye to identify them as a poison. Blue-colored muscle or fat may be a sign that game meat has been contaminated by rodenticides, although this blue discoloration may not always be present. CDFW urges hunters to always use caution when harvesting game animals and be aware of potential risks.
“Hunters should be aware that the meat of game animals, such as wild pig, deer, bear and geese, might be contaminated if that game animal has been exposed to rodenticides,” said CDFW Pesticide Investigations Coordinator Dr. Ryan Bourbour. “Rodenticide exposure can be a concern for non-target wildlife in areas where applications occur in close proximity to wildlife habitat.”
A 2018 study of anticoagulant rodenticide exposure in game animals across California found anticoagulant rodenticide residue in 10 out of 120 (8.3%) of the wild pig and 10 out of 12 (83%) of the bear tissue samples collected largely from animals that were frequenting agricultural or residential areas where rodenticides are commonly/more likely to be utilized.
CDFW encourages hunters to report unusual findings in harvested wildlife, including blue tissue, and not to consume any part of an animal with blue fat or muscle or other abnormalities. Incidents may be reported to the CDFW’s Wildlife Health Lab at WHLab@wildlife.ca.gov or (916) 358-2790.
Pesticide applicators are urged to take measures when applying rodenticides so as not to expose wildlife. Prior to application, it is important to ensure non-target wildlife are not using the area where the pesticide is to be applied. It is also important to use appropriate bait stations and application methods that exclude access to non-target species. Using an integrated pest management approach for rodent control may help reduce the opportunities for rodenticide exposure for non-target wildlife.
For questions about pesticide use and regulations, or to report misuse, contact your local county agricultural commissioner’s office. For Monterey County, call (831) 759-7355.
Visit CDFW’s human-wildlife conflicts web page for more information and resources for managing squirrels and other rodents.
###
Media Contact:
Krysten Kellum, CDFW Communications, (916) 825-7120