Offspring kitten of P-62/NPS

National Park Service researchers recently discovered a litter of four mountain lion kittens in the Simi Hills, a small area of habitat wedged between the larger Santa Monica and Santa Susana mountain ranges. All four kittens are females and are now known as P-66, P-67, P-68, and P-69.

The mother is P-62, who researchers have been tracking since January. Biologists visited the den site while she was away on June 11, locating it after several previous attempts failed because radio telemetry showed that she was still at the den with her kittens. This is the first kitten den researchers have documented in the Simi Hills, between the 101 and 118 Freeways. The kittens were found on the 2,668-acre Santa Susana Field Laboratory site, with cooperation provided by the Boeing Corporation to access the closed area.

“This is the first litter we have marked at the den in the Simi Hills, which happens to be a critical habitat linkage between the Santa Monica Mountains and larger natural areas to the north,” said Jeff Sikich, biologist for Santa Monica Mountains National Recreation Area. “We are very interested to learn about how they will navigate the fragmented landscape and whether they will remain in the Simi Hills or eventually cross one or more freeways to the north or south.”

The National Park Service, along with many other local partners, has been working for decades to preserve and increase connectivity for wildlife between the Santa Monica Mountains and other larger natural areas to the north. As the Simi Hills are immediately north of the 101 Freeway, any animals moving north-south into or out of the Santa Monicas must pass through this area. Except for P-62, the mother of the kittens, every mountain lion biologists have tracked in the Simi Hills (10 so far) has crossed either the 101 or 118 or both, providing valuable information about wildlife connectivity.

Sikich suspected P-62 had given birth after seeing a series of localized GPS locations from her radio collar, indicating that she may be denning. Even with the GPS information, however, determining the location of the den is challenging because the mothers choose locations that are difficult to find.

National Park Service biologists took tissue samples, conducted a general health check, and marked the kittens with ear tags. The blue-eyed, spotted kittens weighed between four and five pounds and were around four and half weeks of age.

This is the 15th litter of kittens marked by National Park Service biologists at a den site. Three additional litters of kittens were discovered and marked when the kittens were already at least six months old.

The National Park Service has been studying mountain lions in and around the Santa Monica Mountains since 2002 to determine how they survive in an increasingly fragmented and urbanized environment. The California Department of Fish and Wildlife is responsible for overseeing the management and conservation of mountain lions in the state.