Rodenticide linked to wildlife, pet deaths in Ojai and throughout the state will soon be banned from stores
By Chris O'Neal 05/15/2014
Jeannine Altmeyer owns a home in Ojai adjacent to an avocado grove. On her property, she raises chickens and other small animals, which in turn attract rodents. After watching as rats swarmed her chicken coop, Altmeyer contacted a local pest control company.
Soon the rats began to disappear, but after finding a dead owl in her yard, Altmeyer noticed that her dog also began acting strangely. A few days later, Altmeyer’s dog died.
Suspecting the poison used on the rats, Altmeyer had an autopsy performed.
“He died from rat poison; that’s 100 percent sure,” said Altmeyer.
For several decades, the pesticides of choice when dealing with rodents, for pest control companies, homeowners and farmers alike, have been products containing brodifacoum, bromadiolone, difenacoum and difethialone — chemicals known as anticoagulants that prevent the blood from forming clots. Eventually, after ingestion, the animal will internally bleed to death.
Altmeyer says that she was told by the pest control company that the poison would not affect animals other than rodents, a claim she says is proven false by her dog’s autopsy report, where her veterinarian confirmed the cause of death from ingestion of anticoagulant poisons.
“The concern is that there’s a lot of wildlife that are eating rats and squirrels,” said Altmeyer. “It’s making them sick.”
After Los Angeles’ Griffith Park mountain lion turned up sickly and mangy last month, accusations of rat poisoning came to the surface. The mountain lion, previously captured on camera in good health, looked sickly and lethargic. Wildlife experts believe that the mountain lion may have ingested the poison used by a local homeowner and now suffers from mange and dehydration and is unlikely to survive.
The Department of Pesticide Regulation has enacted a ban on anticoagulant poisons and, come July 1, homeowners, farmers and others will not be able to purchase them without a proper permit; but their use is still widespread throughout Ventura County and beyond.
Biologist Laurel Serieys has been researching anticoagulant rodenticide exposure in animals, specifically in bobcats.
“We find that more than 80 percent of the animals we test have been exposed to the anticoagulant rodenticide,” said Serieys.
Bromadiolone and brodifacoum are the most common anticoagulant chemicals found in animals, including bobcats, coyotes and mountain lions. Symptoms of poisoning can sometimes be unclear. First-generation poisons — like difenacoum — will cause external bleeding as well and are easier to diagnose. Second-generation anticoagulants, like those used by pest control companies in Ventura County, create no external signs of poisoning.
The most prolific killer of poisoned cats is mange. The parasitic mites can often be fought off by a cat’s natural immune system, but once poisoned the cats become more susceptible, leading to extreme dehydration and, eventually, death.
Serieys says that anticoagulant poisons, first or second generation, should not be used at all.
“If they’re used, they really should be used as an absolute last resort,” said Serieys. “Do we have a bad enough situation that we need to additionally kill wildlife that lives in that area?”
Serieys’ recently tested 24 coyotes and found that 83 percent of the animals were exposed to anticoagulant poisons and 38 percent were exposed to a combination of chemicals that included them. The National Park Service tested 11 mountain lions in the Santa Monica mountain range and found that all but one had been exposed to an anticoagulant.
Ron Rood, owner of Ojai Termite and Pest Control, says that his company is in the process of switching, prior to the July 1 deadline, from anticoagulant poisons to bromethalin, a poison that affects a rodent’s nervous system, paralyzing and eventually killing the animal. Rood says that secondary poisoning with bromethalin rarely occurs and adds that even if he stops usage of the anticoagulants, it won’t stop other companies from using them.
“Because the homeowner uses the anticoagulant the improper way to take care of ground squirrels and stuff like that, I can’t do anything about that,” says Rood. “I get blamed for everything that happens.”
Anticoagulants are distributed through small black boxes that only rodents can enter. Oftentimes, these boxes can be seen around restaurants and in environmentally sensitive areas, such as along the Ventura River, where they’re used to cull the rodent population.
In 2006, the Ventura County Board of Supervisors, acting as the Watershed Protection District Board of Directors, approved the integrated pest management program that dictates what methods can be used, and determines which are most effective, to prevent damage to county dams, levees and other infrastructure.
Ground squirrels and to a lesser extent pocket gophers can burrow under levees, causing damage that, if left unchecked, can be catastrophic. There are more than 600 dams, levees and other facilities within Ventura County; and more than 20 of these are considered critical, meaning that failure could jeopardize public safety.
There is a zero-tolerance policy for burrows on these critical structures, and anticoagulant bait stations that resemble the letter T are considered the most effective way to assure that they remain burrow-free, says Karl Novak, deputy director of the operations and maintenance division of the Watershed Protection District.
Since the 2006 report, the number of bait stations has increased but the area they are being used in has spread out, meaning less concentration in certain areas.
“We are required, by federal law, to prevent any damage by the rodents to levees and dams,” said Novak. “They can burrow right through a levee, and then the levee is like Swiss cheese.”
Novak says that the district is exploring other methods by which to protect the levees, but that the anticoagulants are here for a while longer.
“They’re the best, and these particular anticoagulants are much more mild than what’s been used by homeowners,” said Novak. “It’s a less concentrated version.”
Second-generation anticoagulants are not used by the Watershed Protection District “due to their toxicity,” according to its report.
Altmeyer, however, says that her main objection to the company she contracted with to do home pest control is that they weren’t completely honest about the dangers associated with the anticoagulants for other animals.
“They have to tell people that if you use this, there is a danger to your dog and to the wildlife.”