Published in the Contra Costa Times on November 26, 2006
Question: My backyard has been infested with ground squirrels. Our garden backs up to open space, and they have moved in en masse. They have chewed on our apples, eaten all the almonds, and even ate most of our tomatoes. They also chewed up the drip irrigation lines. We would prefer not to use poisons. What are our alternatives?
Answer: The ground squirrels are native creatures found in most of California. As you have noticed, they eat all manner of fruits, nuts, grains and leafy greens. They can damage trees by chewing the bark off of main trunks and branches.
These squirrels live in extensive underground burrows, but they can and do, climb trees as well, and will forage for food up to 75 feet from home. The communal colonies may have as many as 20 members who spend most of their time underground rearing their young, sleeping, storing food and escaping predators. They do not eat underground roots as gophers do.
In areas with cold winters, they may hibernate, but if winters are mild, they can remain active. In hot summers, adults may go into summer hibernation for short periods of time. Seven to eight young are produced in the spring, and by the time they are 6 weeks old, they are ready to start feeding on your garden or other vegetation.
California Fish and Game laws classify ground squirrels as non-game animals, which allows you as the homeowner to control them using legal means. Controlling ground squirrels can be a challenge.
In residential neighborhoods, using poisons is risky. Dogs become victims more often than cats do, but both are at risk. Because they can climb as well as dig, fencing is not generally effective. Your best choice will be trapping. Instruction and descriptions of various types of traps are available from the Master Gardener office, or by downloading the UC IPM Pest note No. 7438 at www.ipm.ucdavis.edu.
Ground squirrels can carry a number of diseases, including bubonic plague, and must be handled carefully. It is illegal to trap and release ground squirrels outside of your property. Once you have the population under control, you will need to monitor your yard regularly for new populations.
Reach Bethallyn Black at bblack@ucdavis.edu, or 925-646-6586.