~­Written by Kathryn Louyse, Friends of Griffith Park Board member on  JAN 2, 2021

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The long struggle to reduce the use of second-generation rodenticides in California reached its final chapter as Gov. Newsom signed AB 1788 on September 29, 2020. This legislation, aimed at protecting wildlife, found itself in jeopardy several times in the lead-up to final passage and when we say it was a struggle, it’s an understatement. Friends of Griffith Park’s President Gerry Hans noted, “it was a real nail biter” as this legislation was finally passed in the eleventh hour.

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Friends of Griffith Park, and other environmental activist groups are finally celebrating passage of AB 1788 – groups that worked closely with legislators to advocate for this bill. AB 1788 will ultimately save countless lives and bring more balance back to California ecosystems. In a nutshell, the law sets a moratorium on the most potent anticoagulants, restricting rat poisons routinely used by the pest control industry. It’s important to understand there are exceptions, including rodenticide use for declared public health situations, agriculture activities, food storage, and more.

The bill prohibits use of these agents while the Department of Pesticide Regulation completes its reevaluation of second-generation anticoagulant rodenticides. We believe their findings will indicate that use of these rodenticides pose significant, adverse effects to non-target wildlife, so this moratorium would become a ban for the future, an optimistic, expected result.

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However, what’s not included in AB 1788 are the rest of the anticoagulant rodenticides, first generation rodenticides, so there’s still much work to be done. First generation agents are also stubbornly apparent in the food web. In fact, Griffith Park’s beloved P-22 mountain lion was a victim of this group of poisons. He was lucky; he got treatment, but countless other species do not receive this lifesaving treatment.

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The long history of legislative attempts and failures to take anticoagulants off the market underscores how fortunate environmental activists were in getting this legislation passed! One small step at a time is still progress. Here’s the broad strokes why it was imperative to get AB 1788 passed. After all, this wasn’t the first time the bill made the rounds in the California legislature.­

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According to studies conducted by various California agencies such as the California Department of Fish and Wildlife, the National Park Service and others, 80-90% of our predator species – like owls, raptors, bobcats, coyotes and mountain lions – have been exposed to and/or affected by second generation anticoagulant rodenticides (SGARS). More disturbing – a single dose of this rodenticide has a half-life of more than 100 days in a rat’s liver so when rodents are consumed, these poisons can quickly move up the food chain.

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While we know rat poison kills much more than rats, just as significant are the non-lethal impacts weakening populations of various species. As these poisons move through the food chain, effects on wildlife have been devastating. Internal bleeding, mange, and other life-threatening reactions are some of the impacts. Even worse, young chicks are inadvertently poisoned in their nests, leading to even greater losses.

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We know that large cities in California have a rodent problem – because cities have a garbage problem. Humans create massive amounts of garbage every single day, and where does it go? Into trash cans, dumpsters, city and county dumps, and sometimes onto city streets. And where there’s garbage, there will be rats and other pests.

The question then becomes, how do we balance the problem of rodents and trash? In the past, we looked to pesticide companies to create solutions, but solutions generally included the use of harmful rodenticides. Now the challenge will be to create other means of rodent control. In other words, build a better, less destructive to the environment “mouse trap.” Think of all the pivoting and adjusting businesses have made because of the pandemic and you know that humans are capable of coming up with workable solutions. And there is one really simple solution – put trash in proper receptacles and keep the lid on, which will lessen the need for rodenticides. Little steps will help tremendously.

Meanwhile, let’s coordinate with nature and allow predators to do their job. Owls, hawks and coyote can take care of rats on the edges of cities as well as in parklands.

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Restoring the balance lost in nature is the biggest challenge, and passage of AB 1788 is a step in the right direction. Let’s hope this important piece of California legislation will become the template for the rest of the country as well.

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Owl Photo above: courtesy of Allison Brooker.

Sadly, this young owl died from rodenticide poisoning. By eliminating rodenticides, we’re helping to protect raptors, owls and other species. 

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Letter in support for AB 1788 legislation from Friends of Griffith Park

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Beachwood Canyon resident Allison Brooker recently received a call from one of her neighbors about a distressed owl sitting in her yard. Allison knew from experience that owls needed quick rescue. After snapping a photo, Allison called a friend to help her and notified the California Wildlife Center that she would be bringing the owl in for treatment. Her friend arrived bringing a box and towel to help gently corral and transport it to the center.

Ten minutes after the photo was taken, however, the owl died.

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Allison’s rescue effort then turned into a disposal exercise. She took the owl to her veterinarian for cremation and posted pics on Nextdoor. This is when Friends of Griffith Park stepped in.

Hearing about the situation, FoGP president, Gerry Hans realized the owl should be tested for rodenticides and contacted Allison who rushed back to the vet’s office to retrieve the owl carcass. She then passed it along to Gerry who shipped the remains to UC Davis Veterinary Medicine’s California Health, Food and Safety (CAHFS) lab.

A thorough workup at CAHFS includes necropsy, histological work, and lab analyses for heavy metals and anticoagulants. Because Griffith Park is surrounded by residential zones, FoGP has been sending dead animals to this lab for testing to determine cause, especially when there is no obvious reason for the animal’s demise. So far, two coyotes, a fox and a squirrel have been tested at UC Davis with all returning positive results for anticoagulant rodenticide poisoning.

Birds, however, present a more difficult challenge since normally they’re not found quickly enough to extract sufficient liver tissue for the lab work.

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As Gerry suspected, the female juvenile owl did have anticoagulants in its body. In fact, tests showed extremely high levels of difethialone, a potent “second generation” rodenticide. The necropsy showed no fractures, no skin penetrations, but there was hemorrhaging (bleeding) in muscle tissue. The combination of all aspects studied resulted in a conclusive cause of death as anticoagulant intoxication. Likely, a mouse or rat ate the poison from a “bait box” and then the slow moving rodent was nabbed by the owl.

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While second generation rodenticides were removed from store shelves in California in 2014, pest control companies, such as Orkin and EcoLab use them routinely, often without customers realizing these dangerous poisons are becoming prevalent in the global ecological food chain. Second generation rodenticides kill raptors, bobcats and other wildlife that help keep rodents in check, an ironic twist of Mother Nature’s best work!

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Friends of Griffith Park and other environmental organizations have been raising the alarm for quite some time since this struggle is reminiscent of the ban of DDT use across the globe. After three decades of use, DDT was found to imperil many species, particularly raptors such as bald eagles, California condors and peregrine falcons. It’s also been found in various aquatic species which moves up the food chain through consumption. Although DDT use was finally banned in 1972, California condors failed to reproduce in the wild due to thin egg shells, and nearly faced extinction as a result.

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A few facts about anticoagulants…

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• Anticoagulants have long half-lives that bioaccumulate throughout the food web, just like DDT. These poisons travel up the food chain to the top predators. Many studies show exposure at rates of 85% and higher in various species randomly sampled.

• Anticoagulants have shown to produce non-lethal and not readily noticeable effects, just like DDT. For example, suppression of immune response which ultimately decreases life expectancy has been scientifically documented in bobcats.

• Species are threatened by anticoagulants in California, just like DDT. Nearly 100 deceased endangered-listed San Joaquin kit fox were tested positive for anticoagulant exposure.

• Anticoagulants are found across the animal kingdom, just like DDT. Studies show them also in invertebrates (such as snail and insects), fish, ungulates and reptiles.

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