SB 132, authored by Sen. Jerry Hill, D-San Mateo, requires state wildlife wardens to use non-lethal measures, such as capture, anesthetizing or removal, when a mountain lion does not endanger public health or safety. The law goes into effect on Jan. 1.
As before, animals that do jeopardize human life can be shot by state Department of Fish and Wildlife wardens or local officers authorized by the department.
The new law also allows wardens to call on veterinarians, scientists, other government agencies, zoos and nonprofit groups to aid in carrying out an alternative to killing a wandering mountain lion.
"It's a humane solution to a potential community problem," Hill said this week.
Hill will be joined by Half Moon Bay Mayor Rick Kowalcyzk, representatives of the Sacramento-based Mountain Lion Foundation and other supporters in the celebration at 11 a.m. Sunday at Mac Dutra Park in Half Moon Bay.
The Dec. 1 date for the event was intentionally chosen, Hill said, to coincide with the anniversary of the shooting by wardens of two mountain lion kittens that were hiding under the deck of a house on the outskirts of Half Moon Bay on Dec. 1, 2012.
The state wardens were summoned after citizens notified the San Mateo County Sheriff's Office that the kittens were spotted in various locations beginning on Nov. 30.
At the time they were shot, the kittens, which could not be seen clearly in the darkness under the deck, were believed by the wardens to be about nine or 10 months old and weighing 25 to 30 pounds each.
A Department of Fish and Wildlife spokeswoman said department staff believed the animals' behavior, which included having seemingly "blank stares" and remaining immobile when the wardens and a sheriff's deputy tried to shoo them away with strobe lights, was abnormal and therefore threatening.
But necropsy results announced three weeks later showed that the malnourished and apparently orphan kittens were four months old and weighed only 13 and 14 pounds.
Wildlife advocates suggested their behavior was a natural response to fear and an instinct to try to remain hidden and as invisible as possible until it might be safe to leave.
The incident was the impetus for the new law.
"When this happened a year ago, I was just shocked to hear that the two kittens were shot and killed, and then later to hear they weighed 13 and 14 pounds," Hill said.
He noted that wardens "do a tough job" and said the two agents called to Half Moon Bay last year had little choice of action under the law and related department guidelines then in effect.
The new law was written collaboratively by Hill, DFW officials and the Mountain Lion Foundation in an effort to make sure it met state concerns for human safety as well as the goal of protecting non-threatening animals, the senator said.
"Wardens still have the ability to kill mountain lions when the public is at risk. But this legislation gives wardens the flexibility and resources to better deal with the increasing number of mountain lion encounters throughout the state," Hill said.
Even as Hill's proposal was working its way through the Legislature, DFW director Charlton Bonham issued revised guidelines in March containing a number of elements of the law.
Hill said those changes were welcome, but it seemed necessary to put them into law as well because otherwise, the guidelines could be reversed by a future administration in Sacramento.
Mountain lions, also known as cougars, pumas or panthers, are 6 to 8 feet long from head to tail and weigh an average of 140 pounds as adults. Their habitat is mountains and foothills and their main prey is deer.
They are solitary animals, active mostly at night, and their nature is to avoid humans, according to state wildlife officials.
Mountain Lion Foundation executive director Tim Dunbar said the number of mountain lions in California is estimated at 3,000 to 4,000.
Dunbar said the new law is aimed at helping the non-aggressive animal that "wanders into human territory, is not really threatening humans and doesn't want to be there.
"They're just scared and trying to get back to territory they're familiar with," he said.
In 1990, a voter initiative, Proposition 117, established a law that banned the hunting of mountain lions and authorized the DFW to remove or kill any that were an imminent threat to public health and safety.
But Dunbar said that law didn't adequately define what an imminent threat was.
"It was open to any interpretation. The big issue is that clarification. That tweak is needed to improve the original law," he said.
The new addition to the state Fish and Game Code defines an imminent threat that justifies killing as "a situation where a mountain lion exhibits one or more aggressive behaviors directed toward a person."
In other situations, the law requires wardens to use non-lethal actions, defined as capturing, pursuing, anesthetizing, temporarily injuring, marking, providing veterinary care, transporting, rehabilitating, releasing or taking no action against the animals.
California is the first state in the nation to have such a law, Dunbar said.