A mountain lion known as Uno because of an injured right eye has died after being struck by a car late Thursday, Jan. 18.

For two years, UC Davis researchers followed F312’s movement with a collar around her neck, as the lean predator navigated the wilderness areas, hiking trails and roadways of south Orange County, where she died.

“She’s pretty much an icon, this mountain lion with an injured eye who gets around,” said Orange County Outdoors wildlife photographer Mark Girardeau, who twice had encounters in the wild with Uno, both times captured on videos that went viral, adding to the big cat’s fame.

Girardeau was just leaving the area Thursday evening after checking remote cameras he uses to document Uno and other wildlife, when he said he got a call that the mountain lion had been struck near Cook’s Corner on Santiago Canyon Road.

She died from massive head and chest injuries before significant treatment could be started, said Winston Vickers, associate veterinarian at the UC Davis Wildlife Health Center, which also tracks animals locally.

“It’s very disappointing, we had concerns that it could happen because she, like any of the animals in that part of the county, had to cross roads pretty frequently,” he said. “It was always a concern and I think her luck just ran out.”

The most common cause of death for local mountain lions in the area has been being killed while crossing roads and highways, Vickers said.

There have been 140 known fatalities since 1995, 77 from vehicles, in the Santa Ana mountain range, according to UC Davis data. From 2005 to present, there have been 43 deaths from vehicles.

A 2015 study found 46% of all mortalities of collared mountain lions in the Santa Ana Range were from being struck.

Those are just the reported incidents – more animals are hit and die off the roadway undetected, Vickers noted.

Girardeau, who has teamed up with UC Davis since 2015 to share videos, had nicknamed the mountain lion he would see frequently in his footage as Uno because her right eye would give an unusual reflection in photos and videos due to an injury, making her recognizable.

Uno also had a “laissez faire demeanor” around people at times – often paying little attention to hikers or others she might encounter, according to Vickers.

“On one occasion, she walked right past the admission booth at one of the local wilderness parks without even a side glance,” Vickers noted in an obit.

She was just 2 years old when she was captured in January 2022 as part of the UC Davis’ mountain lion study.

She was fitted with a GPS collar and samples were taken, allowing researchers to better understand the health of the animals and where they travel, information used to advise highway agencies where improvements need to be made for safe wildlife crossing, said Vickers.

“F312 taught us a lot in the two short years we knew and followed her life path,” he wrote in the obit.

She had become a mom in her young life, at one time seen with four kittens – though none survived. Two were killed by cars, one on Santiago Canyon Road near where she died.

Uno was able to limp off to nearby bushes following the collision, said Girardeau, who arrived to be by the cat’s side Thursday night as response teams were enroute. The driver was distraught, he said, and stayed at the scene.

It is believed Uno was again pregnant; Vickers said a necropsy expected to happen next week would verify.

She was a favorite for Girardeau to photograph, he said. Twice he encountered her in the wild, having to confront her with yelling so she didn’t view him as prey.

The first time, in 2021, he said he had a two-minute stare down with the big cat. 

In the latest encounter in July, Uno watched him closely, he said, never showing aggression and keeping an eye on him as she passed closely by him on a trail. He thinks she may have recognized his scent from his remote cameras he checks regularly around the area, he said.

“I felt like we had almost a bond, like she knew who I was,” he said. “I knew who Uno was, her travels and what she liked to do.”

A mountain lion named “Uno” for her injured eye was killed by a vehicle collision on Jan. 18, 2024 near Cook’s Corner on Santiago Canyon Road. The four-year-old mountain lion was part of UC Davis research on local populations and was monitored for two years. (Photo courtesy of Mark Girardeau/Orange County Outdoors)

Following the famed mountain lion P-22’s death in Hollywood in 2022 – she also died from injuries after she was struck by a vehicle – Uno was on her way to becoming the region’s most well-known mountain lion, Girardeau said.

Uno liked to travel just north of Whiting Ranch, through Trabuco Canyon and down toward the ocean, visiting creeks and wilderness parks, according to her tracking data.

“It wasn’t unusual for a hiker to see her on a trail. She often times just ignored them,” Vickers said. “She was just an animal who had adapted really well to having to live around that many people,  which is what any mountain lion, especially in south Orange County, has to do.”