Summary

The western gray squirrel (Sciurus griseus) is the largest native tree squirrel in Washington, once ranging widely across oak and pine forests throughout the state (Washington Department of Fish & Wildlife [WDFW], n.d.-a). Today, its range in the state has contracted severely, with only three isolated populations remaining: South Puget Sound, Klickitat County, and portions of Okanogan County (WDFW, n.d.-a). Habitat loss, competition with non-native squirrels, and disease have contributed to this decline.

“The squirrel is a survivor. It is ever-present. It is changeable. The squirrel is legion.”

-Mary Treat, 19th-century American naturalist and entomologist

Description

The western gray squirrel is a striking rodent with a long, bushy, silver-gray tail and sleek steel-gray fur accented with white underparts. Adults can measure up to 24 inches in length, making them the largest tree squirrel in Washington (U.S. Forest Service, 2011). Unlike some mammals, there is little sexual dimorphism in this species—males and females are similar in size and appearance (WDFW, n.d.-a).

A key challenge for the western gray squirrel is competition with non-native squirrels introduced to the region. The eastern gray squirrel (Sciurus carolinensis) is smaller, stockier, and highly adaptable, thriving in urban parks and residential areas. The eastern fox squirrel (Sciurus niger) is larger, with a reddish-brown belly and rusty-colored tail. Both species reproduce quickly, tolerate fragmented habitats, and often outcompete western gray squirrels for food and nesting sites (Stuart & WDFW, 2012; WDFW, n.d.-b).

Feature	Western Gray Squirrel (Sciurus griseus)	Eastern Fox Squirrel (Sciurus niger)	Eastern Gray Squirrel (Sciurus carolinensis)
Size (total length)	22–24 in	18–24 in	16–20 in
Fur Color	Steel-gray back, white underparts	Reddish-brown or orange belly, rusty-colored tail	Gray back, white underparts; can have brownish tones
Tail	Long, bushy, silver-gray	Bushy, often reddish or rusty	Bushy, gray with white edges
Native to WA?	Yes	No; introduced 1920s–40s	No; introduced early 20th century
Habitat Preference	Contiguous oak and pine forests	Open woodlands, farmland edges, urban neighborhoods	Urban, suburban parks; adaptable
Reproduction / Adaptability	Slower reproduction; specialized habitat	Fast reproduction; highly adaptable	Fast reproduction; very adaptable
Identification Tip	Large, silver-gray tail, white belly	Reddish belly, rusty tail; very distinctive	Smaller gray tail, gray belly
Distinctive Sounds	High-pitched “kuk” or “kik” call; alarm or contact call	Loud barking or “rattle” sounds; alarm and territorial	Series of rapid “quaa” or “chirp” notes; alarm or mating call

History of Eastern Gray and Eastern Fox Squirrels in the West

Both the eastern gray squirrel and eastern fox squirrel were introduced to Washington and other western states by humans in the early 20th century. Eastern gray squirrels were intentionally released in Seattle, Spokane, and other cities during the 1920s–30s to provide “charming” wildlife for urban parks (Stuart & WDFW, 2012). Eastern fox squirrels were introduced around the same period, often by private individuals or hunting clubs seeking a game species.

Once established, both species expanded quickly. They tolerate fragmented habitats, reproduce more frequently than western gray squirrels, and thrive in urban, suburban, and open woodland environments. Their adaptability and rapid population growth have allowed them to dominate human-dominated landscapes, often at the expense of native western gray squirrels, which require larger tracts of contiguous oak and pine forest to survive (Stuart & WDFW, 2012; WDFW, n.d.-b).

Status

At the federal level, the western gray squirrel is not listed under the Endangered Species Act. However, in Washington, it is classified as a state threatened species due to its fragmented distribution and population declines (WDFW, n.d.-a). Local extinctions have already occurred in parts of its historical range, such as the San Juan Islands and much of the Puget Sound lowlands.

***** Status References: WA State: WDFW North America: NatureServe Global: IUCN Red List *****

Conservation Efforts in Washington

Washington’s conservation efforts for the western gray squirrel focus on habitat protection and restoration. Programs include:

• Oak woodland conservation – Since acorns are a critical food source, preserving Garry oak (Quercus garryana) stands is essential (WDFW, n.d.-a).
• Connectivity projects – Wildlife agencies work with landowners to maintain forested corridors so squirrels can move between isolated patches of habitat.
• Research and monitoring – Biologists track populations to better understand threats like disease (particularly mange) and the impact of invasive squirrel species (WDFW, n.d.-a).

What Homeowners Can Do in Their Backyard

Even if you don’t live directly in western gray squirrel territory, there are ways for homeowners and landowners to contribute:

1. Plant native oaks and pines – Garry oak and ponderosa pine support native food webs and provide the nuts and seeds western gray squirrels depend on.
2. Protect large trees – Mature forests with big trees provide essential nesting sites. Avoid removing them unnecessarily.
3. Limit pesticide use – Reducing chemicals helps sustain the fungi and insects that are part of a healthy forest ecosystem.
4. Report sightings – If you think you’ve seen a western gray squirrel, report it to WDFW’s wildlife reporting portal. Citizen science data helps track populations.
5. Discourage non-native squirrels – Do not feed eastern gray or eastern fox squirrels, as supplemental food allows their populations to expand at the expense of native western gray squirrels.

By making mindful choices in landscaping and wildlife stewardship, Washington residents can play a small but meaningful role in keeping the western gray squirrel a part of our forests.

Nature Art

This detailed hand-colored lithograph by John James Audubon depicts the western gray squirrel (Sciurus griseus), historically labeled as the “Hare Squirrel” (Plate 43) in The Viviparous Quadrupeds of North America (1845–1848). Audubon likely used the name “Hare Squirrel” because early naturalists often applied names based on superficial features rather than modern taxonomy. In this lively scene, the squirrels are shown chasing each other along a tree branch, with long, sleek tails rather than the fully bushy tails we often associate with tree squirrels today, emphasizing their energetic movement and interaction.

In Smith’s 2025 illustration, a western gray squirrel sits perched on a fence board, nibbling on a small snack, perhaps a nut. The squirrel’s fur is a soft gray, and its tail is notably bushy, capturing the species’ characteristic appearance in a calm, natural moment.

Cover photo credit: Squirrel, western gray (Sciurus griseus (Schmierer, 2009)

References

Click here to view all of the references used for this post

Audubon, J. W. (1845–1848). Hare Squirrel (Plate 43). In The Viviparous Quadrupeds of North America (Vol. 1). University of Michigan Digital Library. Retrieved September 11, 2025, from https://quod.lib.umich.edu/s/sclaudubon/x-b6719889/29377_0042

Massone, M. (2010, December 29). Eastern and western gray squirrels [Photograph]. Wikimedia Commons. Retrieved September 11, 2025, from https://commons.wikimedia.org/wiki/File:Eastern_and_western_gray_squirrels.JPG

NatureServe. (n.d.). Sciurus griseus. NatureServe Explorer. Retrieved September 11, 2025, from https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.104592/Sciurus_griseus

Schmierer, A. (2009, August 21). Squirrel, western gray (Sciurus griseus) (8-21-09) Santa Margarita Lake, SLO Co, CA [Photograph]. Flickr. Public domain (CC0 1.0). Retrieved September 11, 2025, from https://www.flickr.com/photos/sloalan/3843297381/

Smith, I. (2026). Western gray squirrel (photograph of painting). Posted with permission.

Stuart, D., & Washington Department of Fish & Wildlife. (2012). Western gray squirrel conservation in Washington [Fact sheet]. Washington Department of Fish and Wildlife. Retrieved September 11, 2025, from https://wdfw.wa.gov

U.S. Forest Service. (2011, June 6). Western gray squirrel: Sciurus griseus [Species profile]. U.S. Department of Agriculture. Retrieved September 11, 2025, from https://www.fs.usda.gov

Washington Department of Fish & Wildlife. (n.d.-a). Western gray squirrel (Sciurus griseus). Retrieved September 11, 2025, from https://wdfw.wa.gov/species-habitats/species/sciurus-griseus

Washington Department of Fish & Wildlife. (n.d.-b). Eastern gray squirrel (Sciurus carolinensis). Retrieved September 11, 2025, from https://wdfw.wa.gov/species-habitats/species/sciurus-carolinensis