Vertebrate Pest Management

Ground Squirrel

Why are ground squirrels so troublesome?

California ground squirrels (Otospermophilus beecheyi) are rodents that generally live underground. They commonly live in colonies and have a complex social structure. When populations reach a certain threshold, the squirrels become extremely destructive along roadsides, railways, and rangeland. 

California ground squirrels are known to be carriers of bubonic plague, tularemia and many other transmissible diseases. Burrowing by ground squirrels can be very destructive to the environment by causing severe erosion, crop destruction, property damage, and loss of structural integrity to buildings, roadways, and essential infrastructure. Ground squirrel tunneling weakens levees, flood control facilities, canals, and earthen dams. Their burrows undermine the integrity of the water-holding structures, which creates serious legal and safety concerns. They also weaken roadways, railroad berms, building foundations, retaining walls, and landscaping.

Characteristics of ground squirrelsDrawing of ground squirrel tunnels

The burrowing systems of California ground squirrels can range from five to 30 feet. Most tunnels lie within two to three feet of the surface. There can be a single tunnel or a series of complex branching systems. Because they are social animals, each system may be occupied by many squirrels.

Ground squirrels are omnivores. They feed mainly on seeds but will eat nuts, fruits, and occasionally insects. They are active during the day, especially during the warm summer months.

Ground squirrel and burrow opening next to a cracking roadside

Management practices

Contra Costa County uses a proactive approach to control ground squirrel populations. In the areas we treat, our goal is to protect critical infrastructure such as levees, earthen dams, canals, road ways, train berms, and bridge abutments. Failing to manage ground squirrel burrows at these sites creates an unsafe situation and could require considerable maintenance and lead to safety issues.

If you have any questions regarding ground squirrel damage or control, please contact our office for more information.


Resources

California Vertebrate Pest Control Research Advisory Committee

University of California Integrated Pest Management ground squirrel pest notes