Ventura County Turns To Environmentally Friendly Approach To Protect Levees, Dams

Feb 23, 2018

Poisons had long been used to protect levees and dams from rodents. But, now, Ventura County has turned to a more environmentally friendly approach. A South Coast Boy Scout troop is helping the county attract birds of prey to do the work that poisons once did.

Kids from Boy Scout Troop 820 in Camarillo are trekking through a Conejo Mountain Basin in Newbury Park. The basin is also known as a dam, which holds water during storms to prevent flooding. The boys are here to assist the Ventura County Public Works Agency install rectangular-shaped wooden boxes with a large round hole called owl boxes.

“The shape is just so only the owls can get in there and no other predators can get in,” says 14-year-old Alex Ross.

He along with his fellow Boy Scouts built the owl boxes to attract owls to levees and dams so that these raptors can control the rodent population that could otherwise destroy the flood control system.

“We were helping out the environment and helping out all of the animals. And it really made me feel good that I was making a difference,” Ross says.

The boys use a wrench to tighten bolts, nuts and washers that connect the top of a 20-foot metal pole to the owl box.

The boys are helping to install their hand-made owl boxes that are used to attract barn owls. They are also assisting with putting up raptor perches that have wooden stands on top of a 20-foot pole that attract barn and great horned owls as well as red-tailed hawks.

“We attract them to the levees and dams, and then they can hunt,” says Karl Novak, who is Deputy Director of the Watershed Protection District within Public Works.

He says raptors control rodents that can otherwise severely damage flood control systems.

“Ground squirrels and gophers are both very damaging, burrowing rodents. They create very long burrows, up to 25-35 feet long. A gopher can actually excavate over a ton of soil per year,” he says.

Anticoagulant rodenticides, which are poisons that cause animals to bleed to death, have been used to control rodents until the County discovered that hawks and owls do a better job.

Novak conducted a 17-month raptor pilot study in the Revolon Slough in Oxnard.

“We actually saw about 50% less rodent burrows where we put raptor perches than in the areas where we were using rodenticides,” he says.

And that’s not all. The study’s co-author, David Torfeh, an environmental scientist with Public Works, says using raptors instead of poisons also helps other wildlife.

“Secondary poisoning of high level predators is reduced. Poisons travel up the food chain and can cause diseases in things like bobcats and mountain lions,” he says.

“Have you seen that picture of that favorite mountain lion and the Hollywood sign?” asks Ventura County Supervisor Linda Parks.

She pulls out her smartphone to show the Boy Scouts an iconic photo of the majestic mountain lion known as P-22.

“This is him with the Hollywood sign,” she says.

And then Parks shows them a photo of how he looked after being poisoned by rodenticides.

"This is what he looks like with the poisons in him,” she says.

One boy responds, "That’s so sad.”

Parks says she’s thrilled that birds of prey – rather than poison – will now be used to protect levees and dams.

“Really a proud moment for Ventura County because we are leading the way on reducing these potent poisons that are killing off our wildlife.”

The Boy Scouts couldn’t agree more. Fourteen-year-old Rock Steimle says he felt compelled to help.

“This is our generation’s environment, and it’s our era. We have to try to fix it,” he says.