The county of Ventura is rolling out new pest-control methods that — while as unpleasant as ever for the rodents — will present a lower risk of inadvertently poisoning condors, mountain lions and other animals.

The county Watershed Protection District has traditionally used anticoagulant poisons to kill rats and ground squirrels near the district's flood-control facilities. If left unchecked, the rodents can burrow through the earth walls of dams, levees and channels.

"We can't necessarily see the rodent damage until it's too late, so we just have zero tolerance," said Jeff Pratt, the watershed district's director. "If we even see a squirrel in our mission-critical facilities, or even if we don't see a squirrel, we have to do something."

Anticoagulants are effective — the rodents who eat them suffer internal bleeding and then massive organ failure. But they are also imprecise. They travel up the food chain and often kill coyotes, bobcats and other carnivores that eat rodents.

In 2004, two mountain lions in the Santa Monica Mountains died from ingesting anticoagulant poison, perhaps from eating coyotes that had consumed poisoned rodents.

Throughout 2007, the Watershed Protection District tested what is known as "integrated pest management," using far fewer anticoagulants at three of its sites. The results were good — about the same effect on rodent populations using 90 percent fewer pounds of anticoagulant bait — so now, the district is going to use the new methods at the rest of its facilities.

The switch will cost the district about $150,000 per year but should reduce anticoagulant use by 50 to 90 percent. The district's current pest-control budget is about $42,000 per year.

"You'll see a reduction immediately" in anticoagulant use, Pratt said.

The new system won't be completely in place for at least a few months, however, because the district has to hire a full-time employee to manage the new program.

Problems for predators

Seth Riley, a wildlife ecologist with the National Park Service, has studied coyotes, bobcats and mountain lions in the Santa Monica Mountains since 1996. Anticoagulant poisoning is a major hazard for them, he said. It was the leading cause of death among coyotes when he studied them in the late 1990s, and tests of bobcats and mountain lions show "a huge amount of exposure," he said.

"We happen to have been studying bobcats and coyotes and mountain lions, so we can tell you what's going on with them, but who knows about other animals?" Riley said. "We have to assume they're being exposed, too."

Riley said he thinks Ventura County's new pest-control methods will do some good. It's hard to say how much, because anticoagulants are commonly used by private businesses and homeowners, he said.

New methods of control

The Watershed Protection District's old way of killing potentially destructive rodents was to put "bait stations" near dams and levees and fill them with poisoned oat pellets. The stations were usually built out of pipes, and the rodents crawled in and ate the pellets.

"It's a one-size-fits-all solution, and it's cheap," Pratt said, but it uses much more poison than is necessary.

One of the new techniques tested last year is known as "broadcasting" the bait, and it significantly reduces the amount of poison released into the wild.

Instead of leaving the bait out in a station, pest management workers "broadcast," or place, it directly into the squirrels' burrows.

Other methods eliminate the anticoagulants entirely. Pratt said the district is using bait that expands after it's been eaten, essentially making rodents' stomachs burst.

Since the substance isn't toxic, it can't hurt carnivores who eat the rodents.

Staying ahead of the curve

The county has already eliminated anticoagulant use in its government buildings. Patrick Squires, the landscape and custodial manager for the county General Services Agency, said the goal is to keep pests out of the buildings, rather than kill them.

"We're trying not to put anything in the food chain," he said. "Our goal is to use the least lethal method possible."

Those methods include landscaping that doesn't offer spots for insects and rodents to nest; traps, both lethal and nonlethal; and sometimes poisons, although none of them are anticoagulants.

"The whole county is kind of heading in a green direction, and we're trying to stay ahead of the curve," he said.