The Eastern grey squirrel (Sciurus carolinensis) may be cute and fuzzy to on-lookers, especially in the popular tourist areas of Stanley Park in Vancouver, but it is an invasive mammal in British Columbia that is ranked by the Invasive Species Specialist Group (ISSG) as one of the Top 100 Invasive Species in the world.
This small mammal has some big ecological impacts—it has depleted populations of native squirrels through out-competition and disease (parapoxvirus), and displaces native birds of their nesting habitat, eating the birds’ eggs and nestlings. It also competes with native mice and voles.
Economically, Eastern grey squirrels cost homeowners repairs due to digging up of lawns and gardens, chewing through electrical wires, eaves and shingles, and nesting in roofs, attics, and chimneys. Fruit and nut trees and vines may not produce as well due to the bark chewed away from these critters.
Native to central and eastern North America, Eastern grey squirrels take up residence in the deciduous woodlands of the Lower Mainland and Vancouver Island, and it has now made its way into the Southern Interior, primarily in the South Okanagan. In 1909, a small number were released in Stanley Park, where they are now a thriving resident. In 1966, several escaped from a game farm on Vancouver Island, where they pose a threat to sensitive Garry Oak ecosystems.
The Eastern grey squirrel is one of seven mammals among the 173 invasive species identified by the Garry Oak Ecosystem Recovery Team (GOERT) as a species of concern to Garry oak and associated ecosystems. These areas are home to more plant species than any other terrestrial ecosystem in coastal BC, and many of these species occur nowhere else in Canada.
This little critter bites out the tips of the acorns of some oaks, including Garry oaks, which may slow regeneration. They also damage and kill trees by stripping the bark.
Under “Schedule C” of the Wildlife Act, homeowners in BC are permitted to live trap and humanely euthanise or shoot the Eastern grey squirrel. Trapping is most effective during winter months when food is scarce.
Eastern grey squirrels are identifiable by their dark to pale grey backs that may be brushed with cinnamon on hips, feet, and head. Ears are buff to grey to white, and its tail is white to pale grey.
Prevention and persistence are key to management of the Eastern grey squirrel. To prevent their spread, please consider the following measures:
Don’t feed or relocate grey squirrels
Keep all compost, garbage and pet food covered
Use squirrel-proof bird feeders
Please report sightings to your Regional Committee or the Invasive Species Council of BC at 1-888-WEEDSBC. Visit www.bcinvasives.ca for contact information.