Foxes are some of the wildlife affected by rodenticides.
February 3, 2020 at 12:00 pm
Sausalito resident Rona Spiegel has long enjoyed seeing wildlife near her home, and recently she was able to regularly watch an adorable pair of foxes playing. But last week, she sadly discovered one of them dead on her deck. There was no visible trauma or signs of disease. The likely cause: the fox had eaten a rodent that had ingested rat poison. She posted on Nextdoor after finding the fox, writing, “I am sick to my stomach. She was so beautiful, and I wish I could have saved her.”
Spiegel’s heartbreaking discovery happens all too often in our beautiful county. According to WildCare, the most commonly used rat poisons, the “second generation” anticoagulant rodenticides, build up to extremely toxic levels in the rodents that consume them and as they die a slow death, it becomes a tempting meal to a hungry predator like a fox, owl or hawk. Once eaten, that toxic load of poison transfers to the other animal, and the anticoagulant effect causes internal bleeding and often death. In effect, when you poison rats, you poison wildlife.
According to the Center for Biological Diversity and WildCare’s extensive data on the subject, more than 76% of wildlife tested in California in recent years has been exposed to dangerous rodenticides, including more than 25 species.
Even worse, the animals that are getting secondary poison are the same animals that help keep the population of rats and other rodents in check. Owls, coyotes, raccoons, hawks and bobcats all work to balance the ecosystem. Barn owls, for example, are wonderful sources of natural rodent control. A family of barn owls can eat as many as 3,000 rodents in a single four-month breeding cycle, so the loss of just one owl is not just sad, it has a direct impact on the rodent population in the area.
In Marin County, residents are prohibited from using these rodenticides, however, pest control companies are not. If you hire a pest control company, ensure they’re not using these rodenticides. Commercial property owners are also still allowed to use them, so it’s not uncommon to see these “little black boxes” outside grocery stores and restaurants. However, by law, they must be labeled as containing rodenticides. Fortunately, there is a state bill (AB1788) that’s moving its way through the California legislature that would ban the “second generation” category of anticoagulant rodenticides in California, and the use of any rodenticide within California state parks, except for agricultural use.
It’s completely understandable that people want to rid their properties of rodents. The best method of rodent control is prevention. If we remove debris, ivy, construction waste, etc., there are fewer hiding places for rats. It’s also important to eliminate their food sources such as unsealed garbage, fallen fruit and bird feeders left outside at night. A significant percentage of nuisance rodent calls to WildCare 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. Finally, seal openings into your home that are ½ inch or larger.
If you’d like to get more involved in this issue, you can learn more by going to these sites:
• WildCare (
• Raptors are the Solution (
Let’s be good stewards of this beautiful place we’re lucky enough to call home by protecting the residents that have no voice.
Lisa Bloch is the marketing and communications director for Marin Humane which contributes Tails of Marin articles and welcomes animal-related questions and stories about the people and animals in our community. Go to marinhumane.org, Twitter.com/marinhumane, or email email@example.com.