It is useful to start at the end, which is also the beginning: at the far side of an imaginary bridge, picturing a mountain lion slinking over the rise to the east, hugging the shadows and contours of the easy-rolling ridge, then arriving at the 101 freeway’s eight lanes. Mountain lions have died here before, crossing from one sliver of wilderness to another—from the inland, semi-coastal ranges in the Angeles and Los Padres National Forests, across the Simi and San Fernando Valleys, to the Santa Monica Mountains, which run along the Pacific Ocean before elbowing eastward, inland again into the middle of Los Angeles. If the mountain lions don’t die crossing over, those moving westward into the Santa Monicas enter the home range of a famous and stressed-out cat family with a particularly famous son, whose likeness has been printed on magazine covers and T-shirts. The lions here are celebrated and beset upon by all sides—they’re cramped, which is why they are also so ill at ease. It was these cats, the famous group, we were trying to imagine finding a way eastward, over the freeway, escaping L.A.
The crossing point where the bridge might be is named, too perfectly, Liberty Canyon. It is not much of a canyon, more of a dry, narrow valley, or a choke point between a few large hills. We—biologists, ecologists, animal-corridor experts, a few scientists employed by the California Department of Transportation, and I—were here imagining mountain lions and the bridge that they might cross mostly because the bridge will be expensive—many tens of millions of dollars, certainly.
more here.