California Ground Squirrel Quick Tips Natural Pest Control

1. University of California
Statewide Integrated Pest
Management Program
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Ground squirrels feed on and injure many
types of plants, 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 and baits will effectively manage ground squirrels
in landscapes and gardens.
Identification and behavior:
✦ Brownish-gray fur.
✦ Nine 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 seven to eight 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 tripping hazards and
damages landscapes and structures.
How do you manage ground squirrels?
Traps, gas cartridges, and baits are effective against
squirrels at different times of the year. Use with care.
✦ Traps:
• Use kill traps, such as box or Conibear traps,
instead of live-catch traps.
• It is illegal to release squirrels elsewhere without
a written permit.
• Place box 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.
✦ Fumigation (gas cartridges):
• To increase effectiveness, place in
burrows in spring or other times
when soil moisture is high.
• In summer heat, cartridges can
be a fire hazard.
November 2012
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.
For more information about managing pests, contact your
University of California Cooperative Extension office
listed under the county government pages of your phone book
or visit the UC IPM Web site at www.ipm.ucdavis.edu.
What you use in your landscape
affects our rivers and oceans!
University of California
Statewide IPM Program Cooperative Extension
✦ Toxic baits:
• Anticoagulant baits, available at county
agricultural commissioners’ offices and some
hardware and feed supply stores, can be used,
but take care not to poison pets, poultry, or
wildlife.
• Place in bait boxes, and provide sufficient
product for repeated feedings. The squirrels
must eat the anticoagulants in several feedings
during a period of five 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, such as trapping, as soon
as you notice new squirrels and before the population
builds back up.
See Pest Notes: Ground Squirrel at
www.ipm.ucdavis.edu or visit
http://ucanr.edu/sites/Ground_Squirrel_BMP/
for more details.
A pair of box traps baited and set
near a burrow.
California ground squirrel.