Keeping a Weather Eye on Rodents

Orange County flood control worker Jim Dourte was patrolling his area along the Santa Ana River bike path when he abruptly braked his pickup and sprang into action.

“Here’s where I have a lot of trouble,” he said, pointing down a dirt embankment. “Look at all the squirrel holes. There’s one there, there and there! Don’t step on them, they’ll cave in.”

With expert eyes, Dourte focused on dozens of well-dug rodent holes where he had placed poisoned bait stations near Warner Avenue and Harbor Boulevard. “There are holes all over and they can go 100 feet in that direction,” he added, motioning toward the concrete-lined Santa Ana River.

Dourte and two other workers have full-time jobs eliminating varmints as part of the county’s El Nino preparations.

Herbert Nakasone, manager of the county flood program, advised the Board of Supervisors that it’s vital to control squirrels and gophers before they dig through and weaken embankments and dirt levees along the county’s 350 miles of river and flood-control channels.

If enough damage is done, levees and embankments can collapse, according to Dourte’s boss, Bill Hisey, a pest and vegetation supervisor for the county.

In 1983, during California’s last El Nino, the county was held responsible in a civil trial for the failure of an earthen levee that left two Huntington Beach mobile-home parks flooded. At issue: Instead of being lined with concrete, the levee was made of soil, which was riddled with gopher holes.

The rodents have ravenous appetites and strong teeth that enable them to chew and claw through dirt, asphalt, gravel--even wire.

There’s another potential problem: If the pests die or abandon their tunnel, larger animals such as foxes, skunks and ground owls can move in, enlarge the hole and cause structural failure.

The county relies on the rodents’ appetite to help do them in. At bait stations where small blue plastic boxes are placed at ground level, crews place chlorophacinone, an anti-coagulant that also attacks the stomach lining.

“They have to feed a minimum of five days for the poison to work,” Hisey said, adding the county does not use traps and prefers this rodenticide because it’s safer in case it’s accidentally eaten by domestic pets.

Keeping the rodent population down is crucial not only to channel protection but to public health. Hisey said rodents can carry bubonic plague and other diseases and attract fleas. County workers always warn the public not to feed squirrels.

Dourte has learned to detect the whereabouts of his enemy. He looks for freshly dug dirt, or tracks. With gophers, he searches for small mounds. Cobwebs over the holes are a good sign because they indicate no activity.