Rat poison is killing the wrong animals
Editor's note: The following opinion piece was originally published in the Whittier Daily News.
In January, the state of California reported that out of 68 mountain lions that were found dead in the wild between November 2015 and December 2016, all but four had traces of one or more anticoagulant poisons in their livers — the kind of poisons that people put out to kill rodents in their yards.
This summer, hikers discovered two dead foxes, with no wounds or other obvious reasons for death, in the Arroyos & Foothills Conservancy’s Millard Canyon Preserve in Altadena. Another hiker observed a bobcat walking in circles, seemingly catatonic.
What do these events have in common? Rat poison. While we didn’t test the foxes, our biologist experts tell us that they, like the mountain lions, were likely victims of anticoagulant rodenticides.
The death of these foxes sends up a red flag for the danger of rat poisons to wildlife and pets.
Living on the edge of urban sprawl in Los Angeles inevitably means dealing with the wild creatures who have lived here for thousands of years before homes were built, including rodents. But using anticoagulant rodenticide to control the rat and mouse population around homes can expose pets and local wildlife to this deadly poison.
This is because rodents that consume this poison don’t die immediately. A poisoned rodent carries the toxin in its body for up to 10 days before dying. A poisoned rodent may be slow and confused and have difficulty breathing. Anticoagulant rodent bait interferes with blood clotting, ultimately leading to spontaneous, uncontrolled bleeding and death.
As the poison slows the rodent down, your dog or cat — or the wild predators that surround us — might have an easier time catching and eating it. If your pet eats a rodent that has consumed poison, it will be poisoned too. It might have seizures and lose consciousness. Your pet might have difficulty breathing and, without treatment, die.
Long-term, animals that survive rodenticide poisoning have suppressed immune systems, making them susceptible to mange and other diseases. A predator that eats one poisoned rate might not be killed, but its health will suffer. Some of the mountain lions in the study mentioned above had as many as six different kinds of anticoagulant rodenticide in their bodies.
And, of course, everything we’ve said about cats and dogs applies to our wild predators and scavengers such as foxes, bobcats, skunks, raccoons, hawks, owls, coyotes and mountain lions.
After all, they appreciate an easy meal, too! In this way, the rodenticide poison harms more animals than just rats or mice. And it is a gruesome way to die.
P-22, the “Hollywood sign” mountain lion, was a victim of rodenticide back in 2014. The National Park Service tested P-22 when it captured him for a routine collar check and discovered he had mange caused by ingesting rodenticide. They could treat him and he survived, but a female mountain lion, P-34, was not so lucky. P-34 was found dead in Point Mugu State Park in 2015, and testing found that she died from rodent poison.
There are many things you can do to discourage rodents around your house. Many of these recommendations serve double duty, reducing fire hazards, too. Keep a secure lid on your trash, remove debris and thick vegetation from around your home, never feed your pet or leave pet food outside, secure compost piles, remove dense ivy and lush groundcovers that rodents like, and close holes that allow rodents to get into your house, attic and garage. (Steel wool can be inserted into spaces around vents and hoses to prevent rodents chewing a way in.)
If you do have rodents, you can use snap or electric traps to catch them. If you hire a professional, ask him not to use rodenticide. Insist that the company use integrated pest management and sustainable methods that don’t involve anticoagulant poisons, and follow up to be sure.
Even though four anticoagulant rodenticides have been restricted by the state of California since July 1, 2014 — allowed to be used only by certified pest applicators — the poisons are still finding their way into the food chain, killing wildlife and even pets. Sadly, homeowners can still buy these deadly poisons online.
Without natural predators, rodents thrive. Using rat poison is actually counterproductive, as it kills the very predators that keep the rodent population in check. We learned to our sorrow this summer the price of using rat poiso — those two beautiful foxes, dead in Millard Canyon, maybe even the same foxes that we had filmed mating earlier in the year. What a high price to pay for the easy convenience of rat poison.