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Grad student seeks to save bobcats from rat poisons

By Alison Hewitt
Originally posted in UCLA Today

When she checks the traps she sets in the Santa Monica Mountains, UCLA Ph.D. candidate Laurel Serieys hopes to snag bobcats so she can take blood samples for her research before releasing the animals. But more and more, this catch-and-release researcher finds she’s caught a bobcat so sick and emaciated that she rescues them instead, and works with a veterinarian to rehabilitate them.

Serieys’ research at UCLA and with the National Park Service (NPS) was instrumental in discovering that bobcats are dying from mange infections brought on by a toxic build-up of household rodent poisons. Homeowners and pest control agencies put out deadly anticoagulants to kill rats, voles, gophers and other of the bobcats’ favorite meals. The poisons make their way up the food chain, and, according to Serieys' research, more than 90 percent of the bobcats in the Santa Monica Mountains have the toxins in their systems, wreaking havoc on their immune systems.

The wildlife biologist has tried to spread awareness on her own website, Urban Carnivores. Now, to educate people and to raise money for her research, Serieys is working with wildlife photographer Barry Rowan, and the G2 Gallery in Venice on an exhibit that she hopes will lead people to care about the animals she loves.

“Many people I’ve talked to do not seem moved to stop using poisons even once they know that wildlife is being affected,” Serieys said.

“I’m hoping that once they see the beauty of these animals and feel a connection to them, they’ll change their minds,” she continued. “Barry’s photos are pretty spectacular, and he’s captured the bobcats playing and hunting — activities that are rare for even a biologist to see. It’s amazing.”

The exhibit runs from now through Sept. 16, and Serieys will attend a $5-per-person reception on Saturday, Aug. 11, with all proceeds from admission and a silent auction going to her research. Art with a conservation message is G2’s goal, said gallery co-owner Susan Gottlieb.
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“People come into our gallery to see beautiful photos, and then they get hooked by the message,” said Gottlieb, who met Serieys when the student collected a dead bobcat from Gottleib’s garden. “Once I learned about her research, I became really interested, and it just seemed natural to do an exhibit that would help fund her project.”

Serieys is interested in more than just bobcats. She works in the Wayne Lab at UCLA with her adviser, Professor Bob Wayne from the Institute of the Environment and Sustainability and the Department of Ecology and Evolutionary Biology. The lab specializes in conservation genetics, and she takes advantage of the lab’s strengths in using DNA to suss out whether populations are thriving or diving. Her thesis looks at how animals adapt at the urban/wildlife interface — that is, places like the Santa Monica Mountains, where homes in the Hollywood Hills bump up against habitats for wild animals. Bobcats, 1-to-2-foot-tall cats that are much smaller than the mountain lions she also studies, became an unexpected focus for her.

“Her research, along with [that of] other people at the National Park Service, has been very important for establishing that bobcats are severely impacted by rodenticides,” Wayne said. Serieys also works with Seth Riley, an urban wildlife ecologist with Santa Monica Mountains National Recreation Area and NPS.
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“The real surprise of her results and Seth Riley’s results is that the poisons are so widespread and have such a dramatic effect on the population,” Wayne continued. “No one envisioned that that would be the case. It’s a really fascinating axis of research that Laurel is leading.”

“Her Ph.D. work on bobcats is pivotal research,” agreed ecologist Phil Rundel, a professor of ecology and evolutionary biology and at the Institute of the Environment and Sustainability. “Bobcats have been on the decline, and it’s not just because of cars and people. It’s because of rodent poison. Bobcats eat rodents, and Laurel’s one of the first to pin down the connection.”

The poisons weaken the bobcats’ immune systems, making them susceptible to mange. The mites that cause mange — notoedric mange, Serieys specifies — are found worldwide, but until now, “there was never a documented case of notoedric mange causing a population decline. Not in any wild cat species, anywhere,” Serieys said.

“But what we’re seeing in Southern California, and now even in Northern California, is that bobcats are dying of mange,” she said. “And every bobcat we found that died of mange had been exposed to anticoagulants.”

A healthy animal should be able to control the infection, she said, but Santa Monica Mountain bobcats are dying gruesome deaths. Uncontrolled mange makes the animals’ skin itchy and infected, then causes patchy fur loss. Eventually they become emaciated and weak, ultimately succumbing to infection, starvation, hypothermia or a variety of other complications, Serieys said.

She does blood tests on the live animals she catches, and on the animals she finds dead, she does a more telling liver test. The poisons linger for days in the blood, but for up to five months in the liver. Sometimes she finds warfarin, an older poison sold in stores under names like Coumadin and Jantoven. Much more often she finds deadlier second-generation anticoagulants, such as diphacinone, bromadiolone and brodifacoum, which were developed after rats built up resistance to warfarin and which last in the liver even longer.

Her results indicate that more than 90 percent of bobcats are exposed to the poisons, and the numbers are similar for other predators in the Santa Monica Mountains. Nine out of 10 mountain lions tested had ingested the poisons. More than 80 percent of 24 coyotes tested positive for anticoagulants, and even a grey fox and a gopher snake made the list.

“We believe that upward of 90 percent of all predatory animals in the Santa Monica Mountains are exposed,” Serieys said.

Although the Environmental Protection Agency imposed some limits on the residential use of anticoagulants, the poisons are still readily available even for homeowners who aren’t trying to break the rules, Serieys said. The California Department of Pesticide Regulation has opened an investigation to review the effects of the toxins on wildlife, for which Serieys submitted her research. The investigation is an important step, said Wayne, Serieys’ adviser.

“That regulators are curious is important,” he said. “At least we’re getting interest now, and hopefully they’ll begin to think of ways to educate or regulate people.”

It’s not hard to understand the allure for the predators. The poisons weaken their prey, but even a lethal dose can take 10 days to kill a rat, Wayne noted.

“So they slowly bleed to death, and they’re just stumbling around outside,” Wayne said. “The bobcats probably can’t resist.”

While bobcats can’t resist, people can, Serieys hopes. She’s optimistic that this month’s exhibit won’t just help fund her research, but could also be the connection attendees need to convince them to switch from poisons to traps and zappers.

“No matter what poison you put out, you endanger other wildlife,” Serieys said. “People are always asking me for an alternative poison they can use, and I don’t recommend any poisons. That’s a hard pill for people to swallow.”