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Squirrels

Native & non-native species in the Pacific Northwest
Updated Mar 29, 2023
 
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Make a Positive Identification

The most common tree squirrels in urban areas include the native Western gray squirrel, the Douglas squirrel, and two non-native species. In some semi-rural locations, native ground squirrels are active.

Telling squirrel species apart is difficult. Several native squirrel species carry legal protections. They can’t be killed or trapped and released without a special permit. The laws vary by state.

If squirrels are nesting in your attic, contact a wildlife control operator to make sure you comply with your state’s wildlife laws:

They have the expertise, licenses, and tools to get the job done right and minimize risks to your home and family.

See How to Hire a Wildlife Control Operator to learn what to look for in a wildlife control professional.

Common Squirrels
Species: Western Gray Squirrel
Western gray squirrel

Western gray squirrels (Sciurus griseus) are native to the Pacific Northwest. Their fur is white on their belly and silver-gray on the rest of their body. Adults of this species range in size from 19–24 inches long. When disturbed, they make a hoarse barking sound. Populations of the Western gray squirrel are in decline in Oregon. The non-native squirrel species are displacing them.

Species: Eastern Gray Squirrel
Eastern gray squirrel

Rebekah D. Wallace, University of Georgia, Bugwood.org

Eastern gray squirrels (Sciurus carolinensis) are non-native to the Pacific Northwest. They are displacing and out-competing native squirrels. They can host a virus deadly to the native gray squirrels. They look similar to the Western gray squirrel, but are smaller and have more brown and red hairs in their coats. Adults of this species range from 15–20 inches long.

Species: Eastern Fox Squirrel
Eastern fox squirrel

Joseph Berger, Bugwood.org

Eastern fox squirrel (Sciurus niger) is also non-native to the Pacific Northwest. These are displacing native squirrels. Their fur is reddish-brown. Adults of this species range from 18–24 inches long. The Eastern fox squirrel is the most common squirrel in the Portland metro area of Oregon. They breed nearly year-round in the moderate climate of Western Oregon.

OREGON NATIVE SQUIRRELS WITH LEGAL PROTECTION (NON-GAME)
Species: Douglas Squirrel
Douglas squirrel on branch

VJAnderson, CC BY-SA 4.0, via Wikimedia Commons

Douglas squirrels (Tamiasciurus douglasii) live mostly in conifer forests. They are found in some neighborhoods. Populations are declining. They rarely require control efforts.


Helpful

The Douglas squirrel is classified as a Non-game Protected Wildlife species. They can’t be killed or trapped and released without a special permit from the Oregon Department of Fish and Game (OAR 635–044–0430).

Species: American Red Squirrel
American red squirrel on branch

Cephas, CC BY-SA 3.0, via Wikimedia Commons

American red squirrels (Tamiasciurus hudsonicus) are abundant in northeastern Oregon at high elevations. They rarely require control efforts.


Helpful

The American red squirrel is classified as a Non-game Protected Wildlife species. They can’t be killed or trapped and released without a special permit from the Oregon Department of Fish and Game (OAR 635–044–0430).

Species: Northern Flying Squirrel
Flying squirrel

Northern flying squirrels (Glaucomys sabrinus) live in forested areas and are nocturnal. They rarely require control efforts.


Helpful

The Northern flying squirrel is classified as a Non-game Protected Wildlife species. They can’t be killed or trapped and released without a special permit from the Oregon Department of Fish and Game (OAR 635–044–0430).

LOOK-ALIKES: GROUND SQUIRRELS AND CHIPMUNKS
Species: Ground Squirrel
California ground squirrel with spotted fur

Howcheng, CC BY-SA 3.0, via Wikimedia Commons

Ground squirrel species (Spermophilus spp.) range widely in appearance. They all tend to have shorter, less bushy tails than the tree squirrels described above. Most ground squirrels build and use burrows. One species, the California ground squirrel (shown in photo), is known for climbing fence posts, trees, and other structures. They build extensive burrow systems. Ground squirrels can climb small trees but rarely do. 


Different risks or methods

Ground squirrels are a pest of concern in Central and Eastern Oregon. They are also present in the Willamette Valley and adjacent locations. They cause damage to crop fields and earthen structures such as ditches and dams. Their burrows sometimes undermine structural supports.

For management information, see OSU’s Controlling Ground Squirrel Damage to Forages and Field Crops, Ditches, and Dams  (PDF).

Species: Chipmunk
Chipmunk with stripes

ALAN SCHMIERER, CC0, via Wikimedia Commons

Chipmunks (Tamias spp.) are generally smaller and have prominent stripes. They rarely require control efforts.


Helpful

If chipmunks get in your attic or structure, follow the instructions described in this article. To learn more about chipmunks, see Squirrels, Chipmunks and Marmots  (Oregon Department of Fish & Wildlife).

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Squirrels Benefits

  • Squirrels help forests regenerate by spreading seeds that grow new trees.
  • They are a food source for hawks, owls, coyotes, bobcats, and snakes.
  • Squirrels are fun to watch. They are superb acrobats. They have excellent problem-solving skills, especially when trying to get food.
 

Squirrels Risks

  • Squirrels may bite when fed. They carry diseases and parasites that infect people.
  • They build dens inside human structures such as attics when they are able to gain entry. They can chew their way into wooden buildings.
  • Squirrels chew hard objects in order to manage their ever-growing incisors. They sometimes damage electrical wiring (and cause fires), yard furnishings, and even metal doorsteps.
  • Squirrels remove fruit and nut crops from trees. They can quickly strip a tree of its crop.
  • They cause damage to crops, flowers, and lawns by digging and chewing.
  • Squirrels can damage trees by stripping away bark to feed on cambium when other natural food crops fail.
Risk Card
Does it cause harm?
Adults & Children
Low
Property
Some
Pets
Low
Annoyance
Some
Environment
Helpful
Action Depends on Context
 
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Take Action?

Take action for squirrels nesting in attics and structures

Do I need to take action?

  • Remove squirrels that enter your buildings. Keep them from regaining entry.
  • If you grow fruit or nut crops and squirrels are a problem, take preventive action to protect your crop.

What if I do nothing?

  • Squirrels nesting in attics can lead to structural damage and a smelly mess with feces and urine.
  • Squirrels cause damage to fruit trees and gardens, but you can learn to live with them.
 
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Prevent Squirrel Problems

Don’t Feed Squirrels
  • Squirrels fed by people become aggressive when they don’t get food as expected. They lose their fear of people.
  • All rodents have sharp front teeth that can deliver a deep bite. As well as being painful, bites from wild animals may also carry risk of infection and disease transferred via saliva. Native rodents carry diseases, as can their fleas.
  • Close proximity or handling of squirrels creates an unnecessary risk to your health.
Keep Squirrels Away From Bird Feeders
  • Remove bird feeders if squirrels are a problem.
  • Avoid hanging bird feeders from trees.
  • Attach baffles above and below bird feeders to exclude squirrels. Squirrels are very smart and can overcome many attempts to keep them from food.
  • If a tree squirrel can get access to bird food in a feeder or spilled on the ground, it’s likely that mice and/or rats may also benefit from the food source.

 

Squirrel on house roof

Joseph Berger, Bugwood.org

Keep Squirrels From Accessing Structures
  • Close or cover all gaps, holes, vents, broken windows, and chimneys. Squirrels can enlarge holes by gnawing.
  • Trim tree limbs a minimum of 10 feet away from buildings to prevent squirrels from jumping onto roofs.
 
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Solutions for Squirrels
  • Don’t feed squirrels. They become more aggressive when fed. Remove bird feeders if squirrels are eating the bird food, or modify feeders to exclude them.
  • Don’t let squirrels gain access to buildings. Repair any gaps that allow squirrels entry into structures.
  • Use barriers such as wire cages to exclude squirrels from garden beds and fruit crops.
  • Repellents may be temporarily effective.

NEED HELP?

Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon  and other states  can suggest other methods.

Jump to

Method Does it work? Is it safe? Recommendation
A
Block Access to Buildings
Very effective
Low risk
B
Protect Plants with Cages
Effective
Low risk
C
Rodent Repellents
Somewhat effective
Low risk
Use if Necessary
D
Trapping & Relocating
Does not work
High risk
Illegal
E
Rodenticides are NOT ALLOWED for Squirrel Control
 
A

Block Access to Buildings

Non-Chemical Method

Liz Kasameyer, Johns Hopkins School of Public Health, Bugwood.org

Block Access to Buildings

Seal squirrel entry points with wire mesh. The photo shows wire mesh covering a vent on a structure. The wire excludes animals such as squirrels, birds, and rats.

Does it work?
Very effective

Blocking access to your home and structures is required to keep animals from coming back. It is also a key method to prevent animals from damaging structures.

How much effort?
High effort

Use good carpentry practices and sealing techniques to close off entry points.

What's the risk?
Low risk
Possible risk of exposure or harm from chemicals
NONE
Squirrels accessing structure trough damaged facia

tillsonburg, iStock

Examine your structures for potential squirrel entry points such as the one shown in the photo.

How to Exclude Squirrels from Structures

  • Seal squirrel entry points with wire mesh.
  • Repair any gaps that allow squirrel entry to structures.
  • Close openings with ¼ to ½-inch welded-wire mesh. Cover dryer vents, chimneys, and drain/waste/vent pipes with a welded wire screen or cap firmly affixed to the feature.
  • Trim trees to a minimum of 10 feet away from buildings to prevent squirrels from jumping onto roofs.
  • Remove trellises and vines that provide squirrels a way to climb structures.
 
B

Protect Plants with Cages

Non-Chemical Method

pcturner71, iStock

Protect Plants with Cages

Use wire cages to exclude squirrels from vegetables, fruits, and flowers to keep the animals from digging up plants.

Does it work?
Effective

Wire cages must be constructed without gaps to exclude squirrels from entering an area.

How much effort?
High effort

Use good building practices to close off entry points.

What's the risk?
Low risk
Possible risk of exposure or harm from chemicals
NONE
 
C

Rodent Repellents

Chemical Method: Use with caution

Weston Miller, Oregon State University

Rodent Repellents

Use if Necessary
  • Rodent repellents have a strong taste or smell that repels rodents and wildlife without causing them harm.
  • Repellent active ingredients include capsaicin (pepper extract), castor oil, peppermint oil, clove oil, and other essential oils. Other repellents mimic predator scents.
Does it work?
Somewhat effective

Repellents may provide temporary control of squirrels. Most repellent products have not been subjected to objective scientific tests of effectiveness or length of effect.

How much effort?
Moderate effort

You must reapply repellents every two weeks or after heavy rains.

What's the risk?
Low risk

Rodent repellents are NOT toxic baits (rodenticides) designed to kill rodents.

Possible risk of exposure or harm from chemicals
Using animal repellents includes some amount of risk. The lowest risk comes with using alternative methods.

You may be exposed to an animal repellent if you:

  • Get it on your skin
  • Breathe it in
  • Eat or smoke afterward without washing hands
  • Bring it inside on your shoes or clothes

Follow directions closely to reduce risk.

More Information About Rodent Repellents

  • If using repellents, remember to rotate among different products: Animals quickly habituate, or learn to ignore, any signal that is never associated with a negative consequence.
  • Most repellent products must be applied to the surface of plants: Products will lose effectiveness or be washed off completely in repeated moisture or precipitation events and will likewise be degraded by the sun’s UV rays over time. Reapplication and rotation of products is vital.
  • Follow the label instructions about reapplication rates and timing.
 
D

Trapping & Relocating

Not Recommended

"Squirrel Removal" by SheltieBoy is licensed under CC BY 2.0.

Trapping & Relocating

Illegal

Trapping and relocating squirrels is legal in very limited circumstances and only in cooperation with your state’s wildlife control agency.

Does it work?
Does not work

Other squirrels will move in to replace the ones you have removed.

How much effort?
High effort

Trapping and relocating squirrels is best left to professionals who have permits and comply with state laws.

What's the risk?
High risk
  • Relocating squirrels to new areas can spread disease to an otherwise healthy population.
  • Most (more than 50%) translocated animals die a lingering death. Increased risk of predation, starvation, roadkill, and aggression from squirrels already on site contribute to mortality.
Possible risk of exposure or harm from chemicals
NONE

Details about Trapping and Relocating Squirrels

  • Trapping NATIVE squirrels requires a permit. The permit allows them to be captured and released on the same property. You need to coordinate with your state’s wildlife management agency.
  • Live trapped NON-NATIVE squirrels may be released on the same property where they are trapped. Otherwise they must be humanely euthanized.
  • Hunting native squirrels requires a license.
  • We recommend you hire a wildlife control operator with a permit to handle squirrels.

If you want to trap and relocate squirrels, contact a wildlife control operator to make sure you comply with your state’s wildlife laws:

They have the expertise, licenses, and tools to get the job done right and minimize risks to your home and family.

See How to Hire a Wildlife Control Operator to learn what to look for in a wildlife control professional.

 

Rodenticides are NOT ALLOWED for Squirrel Control

Chemical Method: Use with Caution
Hawk eating dead squirrel

cmannphoto, IStock

Rodenticides are extremely toxic to humans, pets, and wildlife. Baits are made to attract animals with tasty smells and flavors. The hawk in the photo could be poisoned if it ate an animal that consumed rodenticide.

Why Is It Important to Read Rodenticide Labels?

  • They have detailed information on how to use the product correctly and legally.
  • They contain information about specific rodent species, their habits, and control methods.
  • They provide information on potential hazards of the product, with instructions you should follow for poisonings and spills.

The Label is the Law

ALWAYS read the label before using rodenticide products. The label is a legal document that provides information on how to safely use the rodenticide. This helps avoid harm to human health and the environment. Using a rodenticide in off-label ways is illegal. It can result in legal enforcement actions.

READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.

Rodenticides (toxic baits) available at stores are NOT ALLOWED for control of squirrels and other wildlife. It is unlawful to use rodenticides in a manner inconsistent with their labeling (instructions).

  • Labels are different for every product and they often change over time.
  • Use a magnifying glass for small print.
  • Pay attention to CAUTION, WARNING, and DANGER statements.
  • Pay attention to the PRECAUTIONARY STATEMENTS.
  • The law states you must read and follow rodenticide instructions.

Storage & Disposal

  • Store out of the reach of children and pets.
  • Follow the label instructions for disposal of rodenticide products.

Call  1-800-CLEANUP (1-800-253-2687) to find out where to dispose of pesticides.

For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call  503-234-3000, email   or visit Metro’s website  

More about:

About Using Pesticides on School Grounds in Oregon

If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management  (Oregon Department of Agriculture).

NEED HELP?

The National Pesticide Information Center (NPIC)  can answer questions about pest control chemicals.
 1-800-858-7378 or npic@ace.orst.edu  

Consider using a licensed pest or weed control company. Learn How to Hire a Pest Control Company.

Your local Extension Specialist in Oregon  and other states  can suggest other methods.


Content provided by editor Weston Miller and writer J. Jeremiah Mann. Vertebrate information edited by Dana Sanchez. Pesticide safety information edited by Kaci Buhl.

 Peer reviewed by OSU Department of Horticulture.

Signe Danler

Signe Danler (Editor/Writer)

Signe Danler is a veteran Master Gardener and landscape designer, with an MAg degree in Horticulture from OSU, and an emphasis on Urban Horticulture. As instructor for the OSU Extension Service online Home Horticulture and Master Gardener Program, she uses her experience and training in gardening, urban forestry and ecological landscaping to communicate about and promote sustainable gardening and landscaping practices.

Photo of Weston Miller

Weston Miller

Project Founder and Content Writer

Weston Miller served as Community and Urban Horticulture faculty for Oregon State University Extension Service for Clackamas, Multnomah, and Washington Counties. Weston is an author for content for this website. He developed funding partnerships with Portland area agencies to initiate and build out the Solve Pest Problems website focused on this goals:

Photo of Dana Sanchez

Dana Sanchez

Dr. Dana Sanchez, Extension Wildlife Specialist, addresses wildlife-related questions on Ask Extension and produces Extension publications, webinars, and presentations to groups such as Master Gardeners. She also conducts research on native mammal species of the West in collaboration with her graduate students and undergraduate research interns.

Photo of Kaci Buhl

Kaci Buhl

At the state level, I lead the Pesticide Safety Education Program (PSEP). The program hosts live recertification events around the state, serving over 1,000 licensed pesticide applicators each year. We also produce web-based training modules and license-preparation study manuals. Special training for unlicensed pesticide applicators is also available through a grant from the USDA Specialty Crop Block Grant Program. The PSEP at OSU works closely with the Oregon Department of Agriculture's Pesticides Division.