City Commission Receives Update on Squirrel and Gopher Abatement

The overpopulation of ground squirrels and gophers in areas like Brookside Golf Course and Hahamongna Watershed Park can become problematic if left unchecked, according to a city staff report to the Parks and Recreation Commission.
Community Services heard an update on squirrel and gopher abatement at its meeting on Tuesday.

“The overpopulation of these pests can pose a public health concern due to the diseases they may carry,” city staff wrote in a report included in the agenda. “Some of the diseases that could be transmitted to humans include typhus and bubonic plague. Additionally the overpopulation of these pests can damage infrastructure, habitat and maintenance equipment.”

According to documents included in the agenda, the city’s parks division has partnered with the Los Angeles County Department of Agriculture to manage the overpopulation of squirrels and gophers.

The city used a variety of methods to catch the rodents, including bait traps and diphacinone.

Diphacinone is an anticoagulant bait that comes in a pellet, liquid and powder forms.

So far, the majority of the chemical mitigation efforts have focused on Brookside, Hahamongna Watershed / Oak Grove park. Defenders Parkway, Eaton Blanche Park and Victory Park are handled by Los Angeles County Department of Agriculture certified applicators.

“Park staff do not engage in any chemical pest control [such as fumigants or bait stations]; however, efforts have been made to explore alternative methods to control overpopulation,” according to a staff report. “The Department of Pesticide Regulation (DPR) and the U.S. Environmental Protection Agency (EPA) have determined that carbon monoxide delivery devices will be regulated as pest control devices, not as pesticides. Park staff has contacted vendors to demonstrate this method to evaluate the applicability to park operations. No determinations have been made at this time.”

Pocket gophers and ground squirrels are classified as nongame mammals by the California Department of Fish and Game.

The populations may be controlled at any time by legal means.

Pocket gophers can inflict damage by invading gardens and lawns as well as agricultural crops.

They can damage trees and also gnaw on and damage plastic water lines and lawn irrigation systems.

Their mounds can interfere and damage lawn mowing equipment.

The mounds also provide a starting place for invasive weeds in landscape and agricultural areas.

Pocket gopher burrows can weaken ditch banks and canals. Irrigation water diverted through their tunnels can be carried away and can lead to soil erosion.