Since 2006, WildCare has been working to combat the use of rat poisons (rodenticides) to control rodents. Why are we against rat poisons? Because rat poisons don’t just kill rodents. They also kill the animals that eat rats and mice, like hawks, owls, foxes, raccoons and skunks.
Shockingly, analysis of the WildCare rodenticide testing data shows 76% of tested animals have a positive result for rodenticide in their blood! Scroll down to learn more.
WildCare is joining forces with YardSmartMarin to spread the word about the dangers of rodenticides to hawks, owls and other animals, and to give Marin residents humane and effective options for controlling rodents.
The best method of rodent control is prevention. Rodents tend to set up camp in our homes when food and space are made available to them.
Remove potential rodent homes like yard debris, trash, construction waste, etc. Remove ivy from on and near structures. Consider removing dense ground-covering plants too. Rats and mice are prey animals, and they much prefer to cross open spaces with the protection of covering vegetation. Removing hiding places deters rodents or makes them more visible to their natural predators.
Eliminate food sources. Keep your garbage completely sealed with lids closed and secured. Keep bulk food, seed, and dry pet food in metal cans with secure lids. Pick up fallen fruit. Take birdfeeders inside at night. A significant percentage of nuisance rodent calls to WildCare’s Living with Wildlife Hotline (415-456-SAVE) relate back to the presence of spilled seed from bird feeders. Place a tray to capture seed under your feeder and empty it nightly, and/or sweep up spilled seed every evening.
Exclude rodents from your home. Seal openings 1/2 inch or larger around the outside of your house with metal, concrete, or Stuf-fit Copper Mesh Wool, which can be found online or at hardware stores.
Include natural rodent predators in your solution. A family of five owls can consume up to 3000 rodents in breeding season. Placing a nest box to encourage a family of owls to make your property home can be a great alternative to commercial pest control methods. Please DO NOT erect an owl box if you or any of your neighbors are using rat poisons! Please visit hungryowls.org for more information.
Use catch-and-release traps as a safe, sanitary, and humane solution. Catch-and-release traps will allow you to remove rodents from inside your home, but you must prevent their return by sealing entrance and exit holes and removing attractants (see above). Remember it is illegal in the state of California and cruel to relocate animals (click to learn why), so trapped rodents should be deposited outside once entry points have been sealed.
If you exhaust all the above efforts and decide to employ lethal methods, please consider purchasing a rat zapper or snap traps. Be careful about where you place lethal snap traps. These traps should only be used indoors out of reach of children or pets. If you find it necessary to use snap traps outdoors, to protect nontarget animals including federally protected birds, traps should be placed in locked tamper-resistant boxes. Never use glue boards, they are not humane and cause extreme suffering to any animal that gets caught in them, including federally protected migratory birds.
Keep in mind that lethal methods will only work if all the other steps outlined above are taken and maintained.
WildCare’s Rodenticide Testing Program
The rat poisons currently available throughout most of the United States and the world build up to extremely toxic levels in the bodies of the rodents that consume them. As the rodent dies, it becomes a tempting meal to a hungry predator. Once eaten, that toxic load of poison transfers, and the anticoagulant effect of the rodenticide causes internal bleeding and often death in the body of the predator.
Even if the dose of poison isn’t enough to kill the predator animal, it is still a highly toxic substance with significant adverse health indications. Many animals carry a “sub-lethal” amount of poison in their blood that may make them more susceptible to injury and illness.
In WildCare’s Wildlife Hospital, animals showing obvious symptoms of rat poison (rodenticide) poisoning, like bleeding from the eyes and nose, lethargy and anemia, are treated aggressively with Vitamin K injections and other anti-rodenticide protocols.
But sometimes patients don’t show obvious symptoms, and the “norms” for blood-coagulation levels (a prime indicator of anti-coagulant poisoning) are not yet standardized in wildlife medicine.
In 2006 WildCare began an initiative to test raptors, foxes, bobcats and other predatory animals for base-line blood coagulation levels and potential rodenticide poisoning. Shockingly, analysis of the data shows 76% of tested animals receive a positive result for rodenticide in the blood over the course of our study.
Most of these patients were admitted for reasons other than symptoms of poisoning (being hit by cars or showing other injuries are the most common), but these test results show that the majority of local predators are functionally living with anticoagulant toxins in their blood. What does this say about the prevalence of these poisons in our environment and the future health of these beneficial (rodent-eating) predators?
The data prove that rodenticide poisoning unintentionally kills the very animals nature has provided to keep rodent populations in check.
Update December 2020 AB 1788
On September 29, CA Governor Gavin Newsom signed AB 1788 in a huge win for wildlife.
The bill puts a moratorium on dangerous second generation anticoagulants until the California Dept. of Pesticide Regulation finishes its reevaluation process.
Too often WildCare sees the damage done to wildlife by these poisons. This is a great win for wildlife and for everyone who supports eliminating these poisons from our environment!
Here is the text of a letter WildCare sent to the Governor, thanking him for his action:
RE: signing of AB 1788
Dear Governor Newsom,
We are writing to express our appreciation for your signing of AB1788, limiting the use of second-generation anticoagulant rodenticides. As you noted in your signing announcement, these rodenticides are deadly for precious wildlife across the state.
As you know, WildCare is based in Marin County and operates a wildlife hospital along with numerous other resources and nature education programs. In 2006 WildCare began an initiative to test raptors, foxes, bobcats and other predatory animals for base-line blood coagulation levels and potential rodenticide poisoning. Shockingly, analysis of the data shows 76% of tested animals receive a positive result for rodenticide in the blood over the course of our study.
Based on our work in our wildlife hospital over the past decade and a half, we remain very concerned about the prevalence of these poisons in our environment and the future health of beneficial (rodent-eating) predators. There rodenticides are a threat not only to mountain lions and wildlife in rural areas, but also in suburban communities like Marin and throughout the San Francisco Bay Area.
We appreciate your leadership in the current pandemic and recognize that you have many vitally important issues on your plate. We are grateful you took the time to look at this issue and sign the legislation. We are not convinced there is any ‘safe’ level of usage of these second-generation anticoagulants and hope you will continue to pay attention as the Department of Pesticide Regulation considers establishing a certification process as called for in the legislation.
With gratitude and sincere thanks for your support.
Kate Van Gytenbeek, President Ellyn Weisel, Executive Director
WildCare Board of Directors WildCare
We also want to thank our friends at Raptors Are The Solution for putting together an excellent call to action on this issue. Here is the press release they issued when the bill was signed (will open as a PDF).