Officials plan to perform a necropsy on a young mountain lion found dead this weekend on Highway 101 near the site of a future wildlife crossing.
Biologists at the Santa Monica Mountains National Recreation Area have been studying mountain lions in the area since 2002 to see how they survive in an increasingly urban area. These efforts include fitting some local cougars with GPS collars.
The exam and additional genetic testing will help scientists learn more about the male cougar, believed to be about 3 years old, likely struck and killed early Saturday. The California Highway Patrol found the mountain lion around 5 a.m. on the south side of the highway near Agoura Hills, between the Chesebro Road and Liberty Canyon Road exits. The animal has since been turned over to the National Park Service.
This mountain lion was not collared, so little is known about its location before its death, said Seth Riley, a wildlife ecologist for the National Park Service. But at that age, male mountain lions usually try to find their own territory.
“We’ve seen this over and over again with these young men,” Riley said.
Why build the crossing at that location?
The small cougar population in the Santa Monicas faces major problems, hemmed in by buildings and highways. These obstacles have led to inbreeding, low genetic diversity and the killing of lions.
Currently, being struck by a vehicle is the No. 1 cause of death in the investigation, Riley said.
The lowest survival rates are in the young adult age group, the toughest time for the cougars, he said. All young men and about half of young women generally try to move elsewhere after leaving their mothers. Therefore, these are also the cougars most likely to use the crossing when it is completed.
The California Department of Transportation is building the Wallis Annenberg Wildlife Crossing over the eight-lane highway near Liberty Canyon. The site is one of the few remaining with natural habitat on both sides of the 101.
Scientists have found that mountain lions and other animals approach both sides of the highway, but few attempt to cross it.
Will the wildlife crossing reduce traffic fatalities?
Few mountain lions and other animals attempt to cross the busy, wide roads, Riley said. The crossing will be critical in reconnecting the Santa Monicas with other areas.
Crossings can reduce the number of wildlife collisions, but also increase those connections and reduce isolation, experts say. One study showed that just one mountain lion crossing the Santa Monicas every few years would help increase genetic diversity.
This young cougar likely would not have been struck at this location if the crossing had been completed. But eliminating traffic fatalities wasn’t the goal of the nature bridge, Riley said.
The crossing will help, but the goal is to allow animals to move back and forth and increase genetic diversity, he said. The bridge is expected to help mountain lions enter the area and others, possibly like the one killed this weekend, to leave.
Officials say they hope to complete the crossing, which is designed to look like a natural habitat, as early as the end of 2025, but have warned this is only an estimate.
Cheri Carlson covers environment for the Ventura County Star. Reach her at cheri.carlson@vcstar.com or 805-437-0260.
This article originally appeared on Ventura County Star: Cougar found dead on Highway 101 near future wildlife crossing
