E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Sciurus carolinensis Gmelin, 1788
Eastern Grey Squirrel
Family: Sciuridae

© David Blevins  Email the photographer   (Photo ID #95)


Distribution of Sciurus carolinensis in British Columbia.
Source: Map courtesy of David Nagorsen

Introduction


The Eastern Grey Squirrel is an introduced species in British Columbia, and is native to eastern North America. It has spread since its arrival in the province and is now found in the lower Fraser Valley, the Okanagan and southern Vancouver Island. In spite of concerns, according to Nagorsen (pers. comm.2012, there is no evidence that this species is impacting the native Douglas Squirrel. Read more below.

Species Description:

This is a large, bushy-tailed squirrel species, larger than the native Douglas Squirrel and Red Squirrel. The head and body length ranges from 23 to 30 cm, the tail from 19 to 25 cm and the adult weight varies between 400 and 600 grams (Wikipedia 2012) There are three colour morphs of the Eastern Grey Squirrels in British Columbia: grey, intermediate (brownish) and black: the black and intermediate colour morphs are a form of melanism (Nagorsen 2005). The grey colour morph is grey on the back, with white undersides. The melanistic form is almost entirely black or brownish with a reddish belly, and is predominant in some regions.. There are also individuals with black tails and black colored squirrels with white tails. Black and intermediate colour morphs are common in the lower Fraser Valley, while the grey colour morph dominates on Vancouver Island (Nagorsen 2005). However, intermediate colour morphs have been observed in Victoria.

Biology

The Eastern Grey Squirrel stores food in numerous small caches for later use. It also builds nests of dry leaves and twigs in the forks of tree branches.

Reproduction:

The Eastern Grey Squirrel breeds twice a year, with two to four young in each litter (sometimes 8 young) (Wikipedia 2012)

Diet:

The Eastern Grey Squirrel eats a variety of foods such seeds, nuts and acorns, and sometimes eats bark. Nuts are the primary food source, and in BC, where nut trees are rare in the Fraser Valley, this squirrel has been observed eating buds and fruit of maples, oaks and hazelnuts; on Vancouver Island Garry oak acorns are a food source (Nagorsen 2005).It is often seen digging up bulbs in gardens and also frequents bird feeders.

Behaviour:

The Eastern Grey Squirrel is a diurnal species, and does not hibernate.

Habitat:

Throughout its range, this species inhabits deciduous forest and wooded habitats, including in urban areas. In BC, it inhabits deciduous and mixed forests.

Global Range:

The native range of the Eastern Grey Squirrel is the eastern United States and adjacent southern Canada; New Brunswick to Manitoba, south to eastern Texas and Florida. However, it has been introduced to other parts of North America and to Europe. It was introduced to the British Isles, Italy, South Africa, and Australia (extirpated by 1973). On mainland Britain, it has almost entirely displaced the populations of native Red Squirrels. It was also introduced to a variety of locations on the west coast of North America, including British Columbia and the states of Washington and Oregon and, in California, to the city of San Francisco and the peninsula area of San Mateo and Santa Clara counties, south of the city. It has become the most common squirrel in many urban and suburban habitats in the western United States north of central California.

BC Range:

In British Columbia, the Eastern Grey Squirrel is found in the lower Fraser Valley, the Okanagan, and southern Vancouver Island. There were two separate introductions of the species in the province, one in Stanley Park around 1914 (an intentional introduction), and one in southeastern Vancouver Island in the late 1960's (three squirrels escaped from a farm). It is now well established in the lower Fraser Valley (east to Chilliwack and south to Boundary Bay), with reports from 100 Mile House and Quesnel. In 2009, it was first reported in the Okanagan (Nagorsen pers. comm. 2012). On Vancouver Island it is found west to Sooke, and north to Duncan.

Carl and Guiget (1958) provide the following information on its first arrival in BC:: "Gray Squirrels were introduced to Stanley Park at Vancouver shortly before 1914. Three or four pairs were released from stock believed to have been obtained in Ontario. They had become established by 1920."

Taxonomy:

Five subspecies of the Eastern Gray Squirrel are recognized. The BC populations are thought to be derived from Ontario populations, which are Sciurus carolinensis pennsylvanicus

Conservation Note :

Displacement of the native Douglas Squirrel and Red Squirrel in BC by this introduced species has been a concern of naturalists and the provincial Ministry of the Environment. Nonetheless, any declines or range loss in the two native squirrel species is more likely the result of the loss of coniferous forest habitat from urbanization on SE Vancouver Island and the lower mainland rather than displacement by the Eastern Grey Squirrel. In eastern North America, Red Squirrels and Eastern Grey Squirrels co-exist but use different habitats. A preliminary study done by a student from the University of Saskatchewan in Stanley Park and Pacific Spirit Park in the lower mainland (see Hwang and Larivière 2006) found little evidence for a decline in the native Douglas Squirrel despite populations of Eastern Grey Squirrels in the parks. However, impact on Garry oak savannas on southeastern Vancouver Island may be a concern, as Eastern Grey Squirrels may kill some acorns before burying them. More research is need to determine the impact of the Eastern Grey squirrel on our native flora and fauna.

Conservation Note Author: David Nagorsen

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
COSEWIC
ExoticSNAExoticNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Photo Sources

Species References

Carl, G. Cliford and C. J. Guiguet. 1958. Alien Animals in British Columbia. British Columbia Provincial Museum, Department of Education, Handbook No. 14. Victoria, BC.

Hwang, Yeen Ten, and Serge Larivière. 2006. A test of interspecific effects of introduced Eastern Grey Squirrels, }i}Sciurus carolinensis, on Douglas’s Squirrels, Tamiasciurus douglasii, in Vancouver, British Columbia. Canadian Field-Naturalist 120(1): 10-14.

Nagorsen, David W. 2005. Rodents and Lagomorphs of British Columbia. Royal BC Museum Handbook. Royal BC Museum, Victoria.

General References


Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2017. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 10/12/2017 6:01:13 PM]
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