Supervisors ask county agencies to avoid using anti-coagulants on rodents
By Charles Levin, clevin@VenturaCountyStar.com
The county Board of Supervisors on Tuesday unanimously told two county agencies to avoid using poisons that contain toxic anti-coagulants, commonly sold chemicals used to kill rodents and mice.
The board told the General Services and Public Works agencies to avoid "to the extent possible" using such poisons at county-owned facilities such as parks, golf courses and flood-control channels.
Supervisor Linda Parks called for the change, hoping to prevent more incidents such as the deaths of two mountain lions in December in the Simi Valley hills. National Park Service officials in February confirmed the big cats died of anti-coagulant poisoning after ingesting bromadiolone and brodifacoum, active ingredients in household rat and mice poisons. The board's resolution also applies to diphacinone and defethialone.
Anti-coagulants prevent clotting and cause animals to bleed to death internally. Parks said she's concerned that the poisons work their way up the food chain. Park Service officials suspect the lions died by eating coyotes who had, in turn, eaten rats or mice poisoned with anti-coagulants.
"I think a lot of people don't realize that when they're trying to get rid of mice and rats in their homes, they're unintentionally getting rid of lions, bobcats and raptors," Parks said after Tuesday's decision.
Seth Riley, a wildlife ecologist for the National Park Service, said many people use anti-coagulant poisons. "A lot of people aren't aware of these ecological effects that can happen," Riley said. "Probably with the board paying attention, it will help people become more aware."
Since 1996, the chemicals have increasingly been found in the carcasses of dead mountain lions, bobcats and coyotes, a wildlife official said at a press conference later Tuesday.
"We have learned that anti-coagulants are pretty widely distributed and may be resulting in significant mortality for wildlife," said Raymond Sauvajot, chief of planning, science and resource management at the Santa Monica Mountains National Recreation Area.
More than 75 percent of bobcats tested after death showed exposure to one or more of the anti-coagulants, Riley said. Also, the bobcat mortality rate has doubled since 2002, Riley said.
Supervisors asked county officials to report back in six months on their progress to eliminate use of the poisons.
Jeff Pratt, director of the county Watershed Protection District, confirmed his agency uses some poisons with anti-coagulants to eliminate squirrels. The rodents dig holes in levees and berms, weakening the structures, Pratt said.
Pratt said his staff would have to research alternative poisons and their efficiency compared with anti-coagulants before reporting back to the board. "We're not experts with poisons," Pratt said.
Rebecca Arnold, deputy director of the General Services Agency, said it does not use bromadiolone and brodifacoum in any county parks. She was unsure about the other two chemicals. The agency also oversees golf courses and landscaping.
"We'll be checking with vendors and staff to ensure that we're not using those (chemicals)," Arnold said.
Parks said there are plenty of nonlethal alternatives, including trapping, fumigants and the use of birds of prey in rodent-infested areas.
The board Tuesday also voted 4-1 to support a bill by Assemblywoman Fran Pavley, D-Agoura Hills, that allows counties to ban the use of any poison that uses one or more of the four anti-coagulants.
Supervisor Judy Mikels voted no, saying the state should ban the use of the chemicals outright instead of pushing it onto counties.
-- Staff writers Zeke Barlow and Sue Davis contributed to this report