Native Squirrels and Introduced Squirrels
When the public is polled regarding
suburban and urban wildlife, tree squirrels generally rank first as problem
makers. Residents complain about them nesting in homes and exploiting bird
feeders. Interestingly, squirrels almost always rank first among preferred
urban/suburban wildlife species. Such is the paradox they present: We want them
and we don’t want them, depending on what they are doing at any given moment.
Although tree squirrels spend a considerable amount of time on the ground, unlike the related ground squirrels, they are more at home in trees. Washington is home to four species of native tree squirrels and two species of introduced tree squirrels.
Native Washington Tree Squirrel
The Douglas squirrel, or chickaree (Tamiasciurus douglasii) measures 10 to 14 inches in length, including its tail. Its upper parts are reddish-or brownish-gray, and its underparts are orange to yellowish. The Douglas squirrel is found in stands of fir, pine, cedar, and other conifers in the Cascade Mountains and western parts of Washington.
The red squirrel (Tamiasciurus hudsonicus,) is about the same size as the Douglas squirrel and lives in coniferous forests and semi-open woods in northeast Washington. It is rusty-red on the upper part and white or grayish white on its underside.
The Western gray squirrel (Sciurus griseus,) is the largest tree squirrel in Washington, ranging from 18 to 24 inches in length. It has gray upper parts, a creamy undercoat, and its tail is long and bushy with white edges. This species is found in low-elevation oak and conifer woods in parts of western and central Washington.
The Northern flying squirrel (Glaucomys sabrinus,) is the smallest tree squirrel in Washington, measuring 10 to 12 inches in total length. It is rich brown or dark gray above and creamy below. Its eyes are dark and large, and its tail is wide and flat. These nocturnal gliders are surprisingly common, yet are seldom seen in their forest homes throughout the state.
Introduced Tree Squirrels
The Eastern gray squirrel (Sciurus carolinensis,) and Eastern fox squirrel (Sciurus niger) were introduced in Washington in the early 1900s. Since then they have been repeatedly released in parks, campuses, estates, and residential areas. They are now the most common tree squirrels in urban areas.
The upper parts of the Eastern gray squirrel are gray with a reddish wash in summer; its underparts are whitish. It’s about 20 inches long, half of which is its prominent, bushy tail. The Eastern fox squirrel measures 22 inches in length, including a 9 to 10 inch tail. Its upper parts are usually dark grayish with a reddish cast, and the underparts are orange to deep buff.
The fur color of these two introduced squirrels can vary greatly. Some individuals, even whole populations, may be almost entirely black.
The increasing number of introduced Eastern gray squirrels is often said to be responsible for the decrease in Douglas squirrels in certain areas. However, given that these squirrels have different food and shelter preferences, it’s likely that increasing housing and other development, and loss of coniferous forests is responsible for any decline in Douglas squirrel populations.
Although tree squirrels spend a considerable amount of time on the ground, unlike the related ground squirrels, they are more at home in trees. Washington is home to four species of native tree squirrels and two species of introduced tree squirrels.
Native Washington Tree Squirrel
The Douglas squirrel, or chickaree (Tamiasciurus douglasii) measures 10 to 14 inches in length, including its tail. Its upper parts are reddish-or brownish-gray, and its underparts are orange to yellowish. The Douglas squirrel is found in stands of fir, pine, cedar, and other conifers in the Cascade Mountains and western parts of Washington.
The red squirrel (Tamiasciurus hudsonicus,) is about the same size as the Douglas squirrel and lives in coniferous forests and semi-open woods in northeast Washington. It is rusty-red on the upper part and white or grayish white on its underside.
The Western gray squirrel (Sciurus griseus,) is the largest tree squirrel in Washington, ranging from 18 to 24 inches in length. It has gray upper parts, a creamy undercoat, and its tail is long and bushy with white edges. This species is found in low-elevation oak and conifer woods in parts of western and central Washington.
The Northern flying squirrel (Glaucomys sabrinus,) is the smallest tree squirrel in Washington, measuring 10 to 12 inches in total length. It is rich brown or dark gray above and creamy below. Its eyes are dark and large, and its tail is wide and flat. These nocturnal gliders are surprisingly common, yet are seldom seen in their forest homes throughout the state.
Introduced Tree Squirrels
The Eastern gray squirrel (Sciurus carolinensis,) and Eastern fox squirrel (Sciurus niger) were introduced in Washington in the early 1900s. Since then they have been repeatedly released in parks, campuses, estates, and residential areas. They are now the most common tree squirrels in urban areas.
The upper parts of the Eastern gray squirrel are gray with a reddish wash in summer; its underparts are whitish. It’s about 20 inches long, half of which is its prominent, bushy tail. The Eastern fox squirrel measures 22 inches in length, including a 9 to 10 inch tail. Its upper parts are usually dark grayish with a reddish cast, and the underparts are orange to deep buff.
The fur color of these two introduced squirrels can vary greatly. Some individuals, even whole populations, may be almost entirely black.
The increasing number of introduced Eastern gray squirrels is often said to be responsible for the decrease in Douglas squirrels in certain areas. However, given that these squirrels have different food and shelter preferences, it’s likely that increasing housing and other development, and loss of coniferous forests is responsible for any decline in Douglas squirrel populations.
This information was provided by the Washington State Department of Fish and Wildlife, Russell Link and Michael Holmquist
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