SAN FERNANDO VALLEY, Calif. — An unprecedented baby boom in the Santa Monica Mountains has the National Park Service dubbing 2020 the "summer of kittens."

Five dens were discovered in just the last three months: four in the Santa Monica Mountains and one in Simi Hills, where a total of 13 brand-new mountain lion cubs were found.

Jeff Sikich, a wildlife biologist with the National Park Service, started his job in the Santa Monica Mountains National Recreation Area in 2002, the very year the service began their long term study of mountain lions.

He says it's the best job in the world, and he's clearly devoted to it. “So first thing I do when I wake up is I look at the mountain lions," he said. "No matter where I am, vacation or not. It’s super interesting to look on a map and see where they are going."

Sikich said the discovery of five litters is great news for a number of reasons. For one thing, having so many dens after the Woolsey Fire is a welcome surprise. "It was such an intense fire, it just scorched the earth," he said. "So it just eliminated habitat for most animals, at least in the near term."

Sikich also believes that at least three of the five litters were fathered by P-63, an adult male who migrated from north of the freeway to the south side of the 101. “It’s likely that he brought new genetic material in, which is definitely positive," he explained. "That’s what our population is really needing."

That's because the Santa Monica Mountains have some of the lowest genetic diversity ever recorded, a threat to their future survival in the region.

Sikich is excited to welcome the new faces, but getting to cuddle the kittens is the result of a lot of detailed work. The search for a den starts with dots and data. By tracking the GPS collars of adult lions, he starts to notice patterns. Mountain lions are solitary animals, so it's always a good sign when he spots a male and a female traveling together for a couple of days.

“I circled 90 days on my calendar from that point because that’s the gestation period for a mountain lion," said Sikich. "Once I saw that female start to exhibit denning behavior — you know, staying in one spot — then I knew, OK, there’s probably a den there.”

Finding it in-person takes a team. A few members use telemetry to keep tabs on the mom, making sure she’s out of the way — "hunting or feeding on a kill, or just taking a break from the kittens," Sikich said.

That's when other researchers hike to about 50 meters from where they think the den may be, and then one of them — usually Sikich — starts the real search.

“They den in areas that are extremely thick, real thick brush," he said, explaining that he often finds himself on the ground for hours, crawling on his hands and knees through poison oak.

The rest happens quickly and quietly. The kittens are brought to the workup site to be examined and tagged. Sikich then returns them to the den and sometimes, when it's possible, he leaves behind a covert camera so researchers can watch the kittens grow.

He says that finding so many dens in such a short amount of time is amazing. "It's good to have some, you know, good news, especially with our lions in the Santa Monica's," he said. "They face so many challenges, both natural but also human-caused."

Challenges includes rat poison, highways and encounters with territorial adult males, to name a few.

For now, Sikich will watch from afar. In a year or so, he hopes to cross paths with these cats again, capturing and collaring them before they disperse as new "dots" he can check in on every morning.