It's possible for wildlife and pets to consume the poison directly. However, it's more common for some animals to receive a secondary exposure from anticoagulant rodenticides. A secondary exposure occurs when wildlife or pets consume dead or dying rodents that have eaten the rodent bait. Wildlife that can be affected by secondary poisoning include owls, hawks, eagles and mammals such as raccoons, foxes, bobcats, mountain lions and coyotes. Tertiary poisoning has also been documented, when two collared mountain lions died of anticoagulant ingestion after eating coyotes that had eaten poisoned rodents. Bromethalin is an acute poison and can kill wildlife that consume it. Several raccoons and skunks have died from eating bromethalin bait and it is critical that it either be used only indoors or in tamper-resistant bait stations.
The most effective and safest ways to address rodent issues are through exclusion and sanitation. Seal off any rodent entrances to your home, remove debris from your yard and make pet food inaccessible to rodents. Traps can also be effective in removing rodent pests. If you use rodent bait, it is important to follow label directions carefully and immediately dispose of any rodent carcasses that result. Rodent baits with the active ingredients brodifacoum, bromadiolone, difethialone and difenacoum are very toxic and persistent and have been found widely in non-target wildlife. They are still legally available to professional exterminators, but to protect wildlife, please encourage those you employ to use other means of control.
Brodifacoum, bromodialone, difenacoum and difethialone are toxic to rodents in a single feeding. However, the rodent will not die until several days after feeding and may continue to ingest more poison. The poison is then available to a predator or scavenger that eats the rodent. If the exposed rodent does not die, the poison can persist in its body for several months, and any animal that eats the rodent will ingest the poison.
Brodifacoum, bromodialone, difenacoum and difethialone are second-generation anticoagulants. Warfarin, chlorophacinone and diphacinone are first-generation anticoagulant rodenticides. Both kinds of anticoagulant rodenticides work by preventing blood from clotting. Animals that ingest them die from internal hemorrhaging (bleeding) several days after ingesting the material. While the mechanism of all anticoagulants is similar, second-generation products (brodifacoum, bromadiolone, difenacoum and difethialone) are much more toxic and persistent, so they pose a much greater threat to non-target wildlife. Bromethalin and strychnine are neural toxicants. Cholecalciferol is an acute rodenticide that causes kidney failure.
Since 1994, CDFW's Wildlife Investigation Laboratory has confirmed at least 400 cases of wildlife poisoning from anticoagulant rodent baits. Brodifacoum was the poison most frequently detected. Species harmed include coyote, gray fox, red fox, San Joaquin kit fox, fisher, raccoon, fox squirrel, bobcat, mountain lion, black bear, Hermann's kangaroo rat, bald eagle, golden eagle, Canada goose, great-horned owl, barn owl, red-shouldered hawk, red-tailed hawk, Cooper's hawk, turkey vulture and wild turkey.
Since animals typically retreat to their dens, burrows or other hiding places in the final stages of anticoagulant poisoning, the number of non-target wildlife killed by these compounds is likely to be much greater than we know. Field monitoring of wild populations of bobcats, mountain lions, coyotes, San Joaquin kit foxes, fishers and raptors confirm widespread exposure to predatory and scavenging wildlife.
Yes! The most effective rodent control program uses exclusion techniques
(sealing the places where rodents enter your home) and sanitation (removing plants
and objects that attract rodents and potential habitat such as ivy or wood
piles); animal removal is used only when necessary. More information on
controlling mice, rats and field rodents is provided on the University of
California Integrated Pest Management
First, do NOT touch it bare-handed. Wildlife can carry diseases and parasites, so always wear protective clothing – especially gloves – before handling dead or dying animals of any kind. If you're in an urban or suburban area, you can call your city or county animal control office with detailed information about the animal's appearance and condition. Even if they don't have the staff to come retrieve it, they may like to know about it, as the one you found may not be the only one.
If your pet is having seizures, is unconscious or losing consciousness, or is having difficulty breathing, phone ahead and take your pet to your local veterinarian or emergency veterinary clinic as soon as possible. If you know that your pet has had access to rodenticide, bring this information with you – especially the name of the product and active ingredient(s) – as it will help the veterinarian effectively treat your pet.