Pests in Gardens and Landscapes: Quick Tips
California ground squirrel.
Open burrow of ground squirrel.
Box type gopher traps set for gopher control.
Ground squirrels injure many types of plants, harbor diseases harmful to humans, and their burrowing damages landscapes. Although similar in appearance to tree squirrels, ground squirrels will always retreat to a burrow when frightened, while tree squirrels will climb a tree or other tall structure and never use a burrow. Traps, baits, and burrow fumigants will effectively manage ground squirrels in landscapes and gardens.
Identification and behavior:
- Brownish-gray fur.
- Body is 9 to 11 inches long, not including a 5- to 9-inch tail that isn't as bushy as a tree squirrel's.
- Live in colonies in a burrow system where they sleep, rest, rear young, store food, and avoid danger.
- Active during the day, mainly midmorning through late afternoon, especially on warm, sunny days.
- Breed once a year, averaging 7 to 8 per litter. When 6 months old, young squirrels resemble adults.
Ground squirrels cause damage by:
- Eating food-bearing and ornamental plants.
- Gnawing on plastic sprinklers and irrigation lines.
- Girdling young trees.
- Burrowing, which causes trip hazards and damages landscapes and structures.
How do you manage ground squirrels?
Traps and fumigants are effective against ground squirrels at different times of the year. Use with care to prevent nontarget poisoning.
- Use kill traps (such as box or Conibear traps) instead of live-catch traps, only when there is no chance of catching a pet or other wildlife.
- Live traps are more appropriate in situations where nontarget species (e.g. cats and dogs) are present. However, once caught, squirrels must be euthanized humanely. It is illegal to release ground squirrels elsewhere without a written permit from the California Department of Fish and Wildlife.
- Place traps on the ground near squirrel burrows or runways. Bait traps with walnuts, almonds, oats, barley, or melon rinds.
- Trapping is effective between February and October when ground squirrels are most active.
- To increase effectiveness, place gas cartridges in burrows in spring, or at other times when soil moisture is high.
- In dry conditions, gas cartridges can be a fire hazard.
- Don't use near buildings.
- Toxic baits
- Anticoagulant baits are available, but take care not to poison pets or other wildlife.
- Place in secure, tamper-resistant bait stations and provide sufficient product for repeated feedings. Squirrels must eat the bait in several feedings during a period of 15 or more days in order for the product to be effective.
- Baits are most effective in summer and fall.
- Always follow label instructions for use.
Where ground squirrels are a problem on property next to wildlands or other infested areas, an ongoing management program is necessary. Squirrels will reinvade over time. Once you have controlled ground squirrels, periodically monitor the area for signs of reinfestation, such as new burrows. Restart control actions at the appropriate time in the squirrel's life cycle as soon as you notice new squirrels, before the population builds back up.
Minimize the use of pesticides that pollute our waterways. Use nonchemical alternatives or less toxic pesticide products whenever possible. Read product labels carefully and follow instructions on proper use, storage, and disposal.