An Urban Wildlife Bridge Is Coming to California

It was just after midnight on April 21st when the radio collar of P-97, an eighteen-month-old mountain lion, sent its last signal. P-97 had only recently separated from his mother, setting out east in the Santa Monica Mountains in search of territory to call his own. (The “P” stands for puma; the number, 97, marks how many mountain lions the National Park Service had tagged when he received the designation.) That night, P-97 reached the 405 freeway, where the parkland of Malibu and Topanga ends and the residential Westside Los Angeles neighborhoods of Brentwood, Bel Air, and Westwood begin. His body was reported to the California Highway Patrol at around one o’clock in the morning, on the southbound side of the 405, near the exit for the Getty Center. His radio collar was missing; his corpse was identified by an ear tag at the West Los Angeles Animal Shelter. Local news broadcasts rolled footage of the black pads of his stilled front paws, a few trails of blood visible on the road behind them.

The following day, a group of nature enthusiasts and dignitaries gathered in a white wedding tent in the suburbs of Agoura Hills. The scent of sage smoke wafted over the assembled crowd as it held a moment of silence for the P-97, and for all the other mountain lions who have died trying to cross the region’s freeways: P-32, who successfully traversed the 101 only to die crossing the I-5, in 2015; P-61, who successfully crossed ten lanes of the 405 near Sepulveda Pass but was killed trying to make a return trip, in 2019; P-104, who was killed in a hit-and-run on the Pacific Coast Highway in March; and more than a dozen others since the National Park Service began tracking the population, twenty years ago. The occasion of the gathering was a proposed solution: the groundbreaking on the Wallis Annenberg Wildlife Crossing, a bridge that will be landscaped with native flora and will span the 101, providing safe passage for mountain lions and other wildlife that are hemmed in by the freeways that surrounds the Santa Monica Mountains; The bridge will guide animals to the wild space and genetic diversity of the Simi Hills, and to the expanse of Los Padres National Forest beyond them, and vice versa. Upon completion—currently scheduled for 2025—it will be the biggest urban wildlife bridge of its kind in the world, and it is intended to serve as a model for other such projects.

It was Earth Day; it had rained the night before, and the sky was a brilliant blue over Liberty Canyon, the site of the crossing, whose hills were blanketed in yellow mustard flowers. The crossing is two hundred feet long and a hundred and sixty-five feet wide; The campaign fund-raising goal is more than a hundred million dollars. It is partly funded by private donors, but construction demands the coördination of a wide array of state agencies: beneath the tent, CalTrans officials mingled with Fish and Wildlife agents and representatives of two state conservation bodies, and National Park Service rangers stood around in uniform , chatting with those whose dermatology suggested their place among the donor class.

The most famous mountain lion in Los Angeles is P-22, who was first caught on camera by a wildlife biologist in Griffith Park more than a decade ago. To get to the park from his likely birthplace, in the Santa Monica Mountains, P-22 successfully crossed the 405 and the 101, perilous passages that left him effectively marooned from his species by a ring of freeways. As Dana Goodyear wrote in this magazine, in 2017, “A lion alone, P-22 is living out of the classic science-fiction narrative of the protagonist who wakes up to discover that he is the last of his kind.” Griffith Park is only a fraction of a mountain lion’s normal territory, but the easy access to mule deer apparently made up for the lack of females. Shortly after he was first seen there, biologists fitted P-22 with a radio collar, which has indicated that he passed through the prime of life settled in his small patch of Los Angeles. During the past ten years, he has regularly surfaced around Griffith Park, startling neighbors, who invariably describe themselves taking a second glance at “a really big dog”; scaring contractors, like those who encountered him in the crawl space of a house in Los Feliz; almost certainly killing a koala bear at the Los Angeles Zoo; and appearing on camera in front of the Hollywood sign, in a shot captured by a National Geographic photographer. On home-security cameras in certain parts of LA, he is a fleeting and ghostly presence, padding past propane grills and leaping over fences. In March, witnesses saw him strolling through Silver Lake, the farthest south that he has been observed to roam. At twelve or thirteen years old, he is near the end of his natural life span, a celebrity but also a symbol of pathos.

If P-22 were more like us, he might take solace in his status as an influencer: since fund-raising for the wildlife crossing began, in 2014, he has been the face of the campaign. At the groundbreaking, visitors took photos next to P-22 cardboard cutouts and wore T-shirts that said “P-22 is my Homeboy.” A rapper from Watts named Warren Dickson performed a song called “We are One.” (“Have you ever heard the story / of P-22 and his journey? / Had to struggle just like me.”) The master of ceremonies was Beth Pratt, a regional executive director at the National Wildlife Federation, who had led the effort to raise the ninety million dollars needed to build the crossing. (California is home not only to mountain lions but also about a quarter of the billionaires in America.) Since 2016, Pratt has undertaken an annual pilgrimage in which she has walked the fifty miles of P-22’s journey wearing a radio collar, with a stuffed likeness of a mountain lion and a cardboard cutout of P-22 strapped to her back. (She used pedestrian bridges to cross the freeways.) She has a tattoo of P-22 on one arm and, for the big event on Earth Day, she wore an extraordinary blue sweater with his face looming over a pattern of cars, lanes of traffic, and the words “SAVE LA’S COUGARS.”

It is possible to live in a city like New York and understand the destruction of the natural environment mostly in abstract terms. In Los Angeles, where wildfires rage, water use is being restricted, and the deaths of mountain lions make the news, such devastation feel nearer. The wildlife corridor represents more than forty years of conservation work, including decades of negotiations to acquire the land on either side of the highway. The site of the crossing has been designated as a critical choke point for wildlife since 1990, and biologists have used collars to track bobcats, coyotes, gray foxes, and mountain lions, in order to document the effects of low genetic diversity caused by highway barriers . Further research found that the genetic divide was not limited to large carnivores but included smaller animals, such as a bird called the wrentit and the western-fence lizard. In an area known for luxury homes in gated communities, the site of the bridge is the only sixteen hundred feet with protected land on both sides of the freeway.

Typically, human interventions to protect the movement of animals represent relatively modest concessions to development. Along a controversial railway line connecting the cities of Nairobi and Mombasa, in Kenya, a wildlife-migration corridor would have been cut off, were it not for six underpasses used by elephants and other fauna—although researchers have found that some animals, including hippos and giraffes, have avoided these passages. There are reindeer viaducts for grazing herds in Sweden; a forested bridge for colugos, pangolins, and nearly seventy other species in Singapore; special lanes for turtles across Japanese rail lines; rope crossings for animals such as sugar gliders and possums in Australia; and a “highway” of flowers and green roofs for bees in Oslo, Norway. Perhaps the most extensive network of crossings in the world is in Banff National Park, in Alberta, Canada; It includes six overpasses, thirty-eight underpasses, and fencing to channel wildlife away from the road. At the time of its twentieth anniversary, in 2017, biologists had recorded more than two hundred thousand crossings by various animals, including lynx, beavers, and toads; Since the network was installed, mortality rates from vehicle collisions for elk in the sections of the highway with crossings have become almost nonexistent.

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