Rodenticides, lack of space threaten local wildlife

This photo of P-25 was taken by a remote camera in June.

Nearly two months have passed since hikers spotted Puma- 25, a one-year-old female mountain lion, dead near Newbury Park. 

Scientists found rat poison in the animal’s system, but were unable to confirm the precise cause of death because of how badly the animal had decomposed. 

Still, the loss of Puma-25 shone a new light on the danger of rodenticides. Recent studies show bobcats and coyotes as the most affected by the toxin, according to National Park Service (NPS). The studies, conducted between 1996 and 2003, tracked bobcats and coyotes in the Santa Monica Mountains.

One study revealed rodenticide poisoning as the second-leading cause of coyote deaths. A bobcat study found very few deaths linked directly to rodenticides, though experts believe rodenticides have sparked an epidemic of notoedric mange, an infection caused by burrowing mites, and killed more than 30 bobcats. 

Duane Tom, a veterinarian and director of Animal Care at the California Wildlife Center, warns that coyotes, bobcats, birds and any other type of animal that feeds on rodents can die from the poison if they eat rodents that have ingested the toxin. 

This happens when the rodenticide, specifically a widely used, long-lasting one called “second generation,” lingers in the predators’ bodies, causing them to bleed to death. 

Reflecting on what he’s learned since he first discovered rat poison killing these animals, Tom asserted rodenticides would counterproductively increase the rat population. He explained that with rodenticides killing off predators that eat rodents, the rodent population could skyrocket. 

“You actually probably end up doing the opposite of what you intend to do,” he said. “In the meantime, your rat population [starts] exploding because they no longer have predators.” 

While mountain lions fall victim to rodenticides far less often than other predators, they still face other survival challenges. 

Film producer Michael Harris has undertaken a documentary project to expose the issue of local mountain lions struggling to access other habitats outside the Santa Monica Mountains. Mountain lions have a natural need to travel to open space, something Harris believes the Santa Monica Mountains needs more of. 

“It’s just this island of habitat, essentially,” he said. 

Mountain lions are forced to wander into populated areas, Harris said. Officers shot one dead last May on Wilshire Boulevard in Santa Monica, and the Sepulveda Pass claimed the life of one in 2011. 

Aside from Santa Monica and the 405 freeway, their quest to find their own territory has also been thwarted by the 101 freeway. The NPS holds no records of mountain lions dying on the 101 in Southern California during an 11-year study of the animal, but it remains a pressing issue that has climbed the bureaucratic ladder to Washington, D.C. 

The Caltrans, NPS and Santa Monica Mountains Conservancy spearheaded a longstanding fight to create a passageway in Liberty Canyon underneath the 101 that would allow the lions to travel from one side of the freeway to the other. 

The planning phase happened in 2003, and in 2004, the three agencies pursued a $10.9-million federal grant and $1.49 million in state and local dollars to fund the project. 

But as time passed, federal money grew scarce amid the dwindling economy, and the local dollars went to Oakland, Calif., to bolster a park project. The decision outraged local officials, as they felt the passageway project carried more environmental importance. 

Harris feels the project would become a landmark improvement. 

“That would be a great legacy for this region, and a case study for what other areas [and] regions can do,” he said. 

And since mountain lions feed off of deer, Harris predicted the project would preserve the local deer population and help avert a serious food chain crisis. 

“Without the apex predator, the whole ecosystem will collapse. You’ll see an explosion of deer,” he said, adding that they will eat up the grass and eventually starve. 

For now, the agencies have their sights on reapplying for funding when the economy improves. 

They also are crossing their fingers to receive part of a federal $50 billion stimulus for transportation, pending the outcome of Washington’s fiscal cliff battle, and that no state transportation money gets funneled into the general fund.