3 mountain lion kittens in Simi Hills become 25th local litter marked by researchers

World, meet P-113, P-114, and P-115.

That’s the designation for three healthy, month-old female mountain lion kittens that biologists recently discovered nestled in a dense patch of poison oak growing around large boulders in the Simi Hills.

The sisters belong to P-77, a 5- or 6-year-old lion who biologists captured and radio-tagged in the same area a few years ago. Researchers hope to do the same with the three kittens late next year, just before the girls get old enough to leave their mom.

Tagging these lions is part of a National Park Service study that’s been going on in and around the Santa Monica Mountains since 2002, in an attempt to determine how the cats survive — or don’t — and what might help to stabilize their threatened existence.

Each year, local mountain lions are killed trying to cross nearby freeways, by poachers, and through exposure to rat poison and other hazards that come with living so close to an urban center. Fenced into the area by the 101 and 405 freeways, and other man-made obstacles in other parts of Southern California, area mountain lion populations are struggling with the effects of inbreeding that researchers say could one day wipe them out. And last year was a particularly brutal one for local mountain lions, including the death of world-famous P-22.

That’s why researchers are excited to see three healthy females born into the area, said Jeff Sikich, lead field biologist for the NPS mountain lion study.

“We need greater genetic diversity for our mountain lion populations,” Sikich said, adding that more females are particularly needed to boost reproduction rates.

A few weeks before they spotted the kittens, Sikich said his team noticed through GPS points from P-77’s radio tracker that she was spending extensive time in one area. Three to five days in one spot might indicate she’d taken down an adult deer she was feasting on, he said. But after she stayed put for a week and a half, in late April, he said they were confident she’d given birth.

So on May 18, he set out with a small team to the area where P-77 had lingered. They waited until her radio collar indicated she’d left the area, then got within 70 meters of the hotspot. One team kept an eye on P-77’s location, so they could steer clear if she started heading back. As they drew closer, Sikich approached alone in an effort to disturb the area as little as possible.

About half the time he goes out searching, Sikich said he hears the kittens first. This time he spotted them, despite the dense poison oak they were hiding in. The plant doesn’t trigger reactions in mountain lions the way it does many humans, he noted. Not as lucky, Sikich climbed in carefully, gloves and mask in place, to grab the kittens and take them back to two researchers waiting nearby.

There in the field, the team checked the sex of each kitten. They also weighed them, with all three coming in at a healthy three to four pounds. They took biological samples, which they’ll soon use to do some genetic mapping. And they put small, color-coded markers on each ear so they can identify the kittens later if they’re spotted on wildlife cameras. When the kittens get old enough, researchers will try to put radio collars on them.

The team has similarly marked 24 other litters at their den sites since the study started 21 years ago. They marked four additional litters when the kittens were at least six months old and traveling with their mother.

The identity of the kittens’ dad remains a mystery. And Sikich suspects it’ll remain that way even after they do DNA sequencing, since he said they haven’t been following any males in this area of late. That means he likely came from the Santa Susana Mountains, rendezvoused with P-77, and then returned home.

The last two adult males regularly tracked in the Simi Hills were P-64, who died during the Woolsey Fire in December 2018, and P-38, who was poached in July 2019.

This is the first litter of kittens spotted in the entire region since last summer, when researchers tagged two sets of kittens. They spotted three of those kittens on wildlife cameras a month or so ago, Sikich said, so they’re optimistic about survival rates. And they hope to track those lions in late fall to add radio collars.

The most recent litter marked in the Simi Hills was in 2020, when P-67 gave birth to a boy and a girl. But P-67 was found dead that same day, with inflamed intestines and rat poison in her system. Researchers tried to get another area lion to foster the cubs, but eventually had to send them to a conservation center in Arizona.

The Simi Hills are a small habitat area between the larger Santa Monica and Santa Susana mountain ranges, with the 101 and 118 freeways on either side. P-77 has established her adult home range in this area, though she’s previously crossed both freeways and has spent short periods in the Santa Monica and Santa Susana mountains.

As the three new sisters grow, Sikich said it’ll be interesting to see if they stay in this narrow area or if they attempt to cross surrounding freeways to enter larger habitat areas.

Freeway crossings are always treacherous. That’s why construction is underway now on what will be the largest wildlife crossing in the world, with a grass-covered bridge set to cross 10 lanes of the 101 freeway in Agoura Hills.

That project should wrap up in early 2025 — right around the time P-113, P-114, and P-115 will be due to leave their mom’s side.

With any luck, Sikich said researchers will get to “watch” via radio pings as the sisters use the bridge to safely make their way into the world.

Source: Orange County Register