Écureuil gris— species and hunting in Quebec

The eastern gray squirrel (Sciurus carolinensis), spelled as grey squirrel outside of the United States, is a species of tree squirrel in the genus Sciurus. It is native to eastern North America, where it is the most prodigious and ecologically essential natural forest regenerator. Widely introduced to certain places around the world, the eastern gray squirrel in Europe, in particular, is regarded as an invasive species. In Europe, Sciurus carolinensis is included (since 2016) in the list of Invasive Alien Species of Union concern (the Union list). This implies that this species cannot be imported, bred, transported, commercialized, or intentionally released into the environment in the whole of the European Union.

Habitat and range

Sciurus carolinensis is native to the eastern and midwestern United States, and to the southerly portions of the central provinces of Canada. In the mid-1800s the population in the midwestern United States was described as being "truly astonishing," but human predation and habitat destruction through deforestation resulted in drastic population reductions, to the point that the animal was almost absent from Illinois by 1900. The native range of the eastern gray squirrel overlaps with that of the fox squirrel (Sciurus niger), with which it is sometimes confused, although the core of the fox squirrel's range is slightly more to the west. The eastern gray squirrel is found from New Brunswick, through southwestern Quebec and throughout southern Ontario plus in southern Manitoba, south to East Texas and Florida. Breeding eastern gray squirrels are found in Nova Scotia, but whether this population was introduced or came from natural range expansion is not known. A prolific and adaptable species, the eastern gray squirrel has also been introduced to, and thrives in, several regions of the western United States. In 1966, this squirrel was introduced onto Vancouver Island in Western Canada in the area of Metchosin, where it is considered highly invasive and a threat to both the local ecosystem and the native squirrel, the American red squirrel. Overseas, eastern gray squirrels in Europe are a concern because they have displaced some of the native squirrels there. For example, in Britain, they have largely displaced the red squirrel; in Ireland, they compete with the Eurasian red squirrel. They have also been introduced into Italy, South Africa, and Australia (where they were extirpated by 1973).