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Another Mountain Lion Braves the 101, Underscores Importance of Wildlife Crossings

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Why did the kitten cross the road? Well, you know. | Photo: National Park Service

Apparently it runs in the family. Just a month after Santa Monica Mountains mountain lion P-33 made the first successful puma crossing of the Ventura Freeway in six years, her brother P-32 has followed, leaving the Santa Monica Mountains for the more spacious open country in the mountains north of the San Fernando Valley.

P-32, pictured above, apparently made the dangerous northward crossing by dashing across seven lanes of Highway 101 between Camarillo and Conejo Valley, about a mile east of where his sister made the crossing in mid-March. Though P-32 seems to have made it across safely and is now prowling the Simi Hills area, he and his littermate were extremely lucky. The last known successful puma crossing of the 101 took place in 2009, with at least two pumas having died in making the attempt.

Being able to cross the 101 corridor is crucial for the long-term viability of the increasingly inbred Santa Monica Mountains puma population. While wildlife watchers greeted news of P-32's dispersal north of the Valley with some relief, the long-term outlook for pumas between Griffith Park and Point Mugu is bleak -- unless we can make it easier for the big cats to cross the 101 safely.

The previous crossing was made in 2009 by puma P-12, who crossed the freeway from north to south into the Santa Monicas.

P-32, P-33, and another sister P-34 were born near Malibu Springs in 2013. (We remember it like it was yesterday. They grow up so fast.) In December 2013 we wrote:

These babies won't have it easy: their habitat is hemmed in on all sides by either cities or ocean. And whoever their dad turns out to be, it's very likely that he's far too closely related to mama P-19 than is strictly advisable from a genetic diversity standpoint. But facing the traffic, and unfriendly humans, and the other rigors of life in the Southern California urban-wildland interface comes later.

It looks as if two of the three, at least, are pretty good, or pretty lucky, or both, when it comes to navigating freeway-choked southern California. But puma partisans aren't willing to rely on luck: they'd rather make sure California's top predator has at least a couple safe places to cross freeways. At the top of the list of potential spots in Los Angeles County: the Liberty Canyon interchange near Agoura Hills, where a male lion from the north met his sad end in 2013 trying to bring some much-needed genetic diversity into the Santa Monicas.

Liberty Canyon is one of the last remaining places along the 101 corridor where there's open space on either side of the freeway. A wildlife crossing would connect the Santa Monica Mountains National Recreation Area with the Upper Las Virgenes Canyon Open Space Preserve, and from there to lion country in the Transverse Ranges and beyond.

A tunnel crossing would likely cost about $10 million to build, with an appropriately landscaped overpass for wildlife even more expensive. In January, the California Coastal Conservancy awarded Caltrans $1 million to fund a preliminary study of the project.

Until that crossing is completed, pumas on either side of the Ventura Freeway must gauge whether to venture out into high-speed traffic, just one of the many highways posing a serious threat to pumas in the state.

P-32 and P-33 made it, this time. The next time, the siblings, or any of the region's other pumas, may not be so lucky. "Almost all of the young male mountain lions we've studied die prematurely, either from a vehicle collision or after a fight with a dominant adult male," said Dr. Seth Riley, a wildlife ecologist for Santa Monica Mountains National Recreation Area. "It's hugely significant that P-32 was able to disperse out of the Santa Monica Mountains so that he has a chance to avoid larger males and eventually establish his own territory."

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