NPS reports 2 new cougar deaths

Rat poison named as culprit

ANOTHER GONE—A 6-year-old male mountain lion known as P-30 was found dead at Topanga State Park with no signs of injury or trauma. Courtesy of NPS

ANOTHER GONE—A 6-year-old male mountain lion known as P-30 was found dead at Topanga State Park with no signs of injury or trauma. Courtesy of NPS

Poisons used to kill rodents and pests have been linked to the death of one puma in the Santa Monica Mountains and may have contributed to a second, the National Park Service said this week.

A healthy 6-year-old male mountain lion known as P-30 died from the effects of anticoagulant rodenticide poisoning, NPS said, and another, P-53, was found with high levels of chemicals in its body.

P-53, a 4-year-old female, was too badly decomposed to determine an official cause of death, park officials said.

On Sept. 9, NPS biologists hiked into Topanga State Park to look for P-30 after his radio collar put out a signal indicating he had died. He was found dead with no obvious signs of injury or trauma, according to a park service statement.

This iconic remote camera shot captured P-30 in 2013 when he was only 3 months old. He was the only male in his litter and eventually become the first male lion kitten tracked by the National Park Service to have survived long enough in the Santa Monicas to reach adulthood and establish a home range. Courtesy NPS

P-30’s carcass was collected, and a necropsy by the California Animal Health and Food Safety Laboratory field office in San Bernardino revealed that he bled to death internally, one of the effects of ingesting rat poison.

Mountain lions are most often exposed through secondary or tertiary poisoning, meaning that they consume an animal like a coyote that ate the prey, a rat or ground squirrel, that originally ingested the bait.

Testing showed P-30 had five different types of anticoagulant rodenticides in his system.

Park officials say it’s the fifth confirmed mountain lion death from poisoning since their study of the big cats began 17 years ago.

Since 2002, NPS researchers have documented the presence of anticoagulant rodenticide compounds in 23 out of 24 local mountain lions that they have tested, including in a 3-month-old kitten.

The laboratory did not find a cause of death for P-53. Her carcass was too decomposed by the time biologists reached her on Aug. 15 in Malibu.

But testing did identify four different compounds of anticoagulant rodenticide in P-53’s liver.

A close-up of P-53, the so-called “Surprise Cat.” According to the National Park Service mountain lion profile page, she was presumed dead for several months shortly after her birth until she was found at the site of a deer kill. She was last collared in March 2019 and treated for mange, the NPS says. Courtesy NPS

“Just about every mountain lion we’ve tested throughout our study has had exposure to these poisons, generally multiple compounds and often at high levels,” said Seth Riley, ecologist and the wildlife branch chief for Santa Monica Mountains National Recreation Area.

“A wide range of predators can be exposed to these toxicants —everything from hawks and owls to bobcats, coyotes, foxes, and mountain lions. Even if they don’t die directly from the anticoagulant effects, our research has shown that bobcats, for example, are suffering significant immune system impacts,” Riley said.

Testing of P-64, who died a few weeks after the Woolsey fire, also revealed six different anticoagulant compounds in his liver, as did testing of P-47 who died from poisoning in April of this year.

Though most local public agencies have ceased using the poisons, they remain readily available in stores and are not illegal to use.

Assembly Bill 1788, introduced this year by Assemblymember Richard Bloom (D-Santa Monica), would ban the use of second-generation anticoagulant rodenticides. The bill remains in committee.

The National Park Service noted that cougars in the Santa Monica and Santa Susana mountains are still more likely to be struck and killed by a vehicle than by consuming rat poison.

Another cause of early death among mountain lions is when they attack each other due to territorial limitations brought about by urban development, experts say.

Acorn staff report