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Squirrel
Releasing two dozen Eastern grey squirrels in Stanley Park around 1914 was a nutty idea. Perhaps second only to the bad idea of introducing starlings to North America. The non-native squirrel stayed in the park for decades but suddenly, in the 1980s, there were sightings all over Vancouver and Vancouver Island. Now the furry fiend has become a pest throughout the Northwest, digging up gardens for bulbs, chewing through eaves and shingles to make nests in attics, and taking over bird feeders.
Karl Larsen, Professor of Wildlife Ecology and Management at Thompson Rivers University is studying the invasion since this species is now considered one of the top 100 invasive species in the world. In Europe, grey squirrels were introduced to Britain, Ireland, and Italy, and in all three countries have spread and replaced the native European red squirrel. It is anticipated that the squirrels will occupy every country in Europe within two decades.
Invasive species are a big problem for agriculture, and for biodiversity. Is the Eastern Grey Squirrel the next big threat to B.C.’s orchard and vineyard industries? Probably not, but growers need to familiarize themselves with the new squirrel on the block that has recently moved into the central Okanagan and Thompson.
First let’s look at our native squirrels, their habits and habitats. The Douglas squirrel is found in the Lower Mainland, while its close cousin the red squirrel lives in all other areas of the province. The Douglas squirrel is reddish brown with cinnamon undersides while the red squirrel is tan or grey-brown with pale undersides. Both squirrels occur in coniferous or deciduous forests feeding on cone seeds and often making big piles of cast-off seeds. These small native trees squirrels fiercely defend their territories so squirrel densities are usually about one per hectare.
The Eastern grey squirrel is either grey or black in colour and is twice the size of the native squirrels and has a large, bushy tail. This species allows its territory to overlap with others, so squirrel density is much higher where they have taken over. It does well in urban habitats, being comfortable on the ground scrounging handouts and preferring urban edges to denser stands of native forest. The native squirrels prefer coniferous seeds and habitats where trees touch so that they can travel across branches.
Both squirrels will eat buds, mushrooms, fruits and small bird nestlings when they are available. Grey squirrels have become a problem in hazelnut orchards in Europe, but so far are not a major pest in fruit trees or orchards. It is not an animal that likes open country, fields, or vineyards, although it is causing trouble in hazelnut plantations in Italy. This new squirrel may follow the pattern of the Eastern Fox Squirrel, which was introduced to the American Okanagan in 1948, showing up in Osoyoos about 1974 and slowly spreading north in low numbers.
Unfortunately the larger, more gregarious Grey Squirrel is having an ecological impact on songbirds, competing for food and eating bird eggs and nestlings. It depletes populations of native squirrels and mice after it moves in through competition and disease.
To help prevent the establishment of this alien species don’t feed them. Second, never trap and relocate them. This “kind” approach to wildlife management is likely what is causing the population explosion in British Columbia as people trap, but do not euthanize the animals they catch. The same applies to all rodents that are trapped—trap and humanly kill, never relocate. You are just spreading the problem. Keep in mind that relocation is not permitted for invasive species.
Under “Schedule C” of the Wildlife Act, property owners in B.C. are permitted to live trap and humanely euthanize or shoot the Eastern grey squirrel. Trapping is most effective during winter months when food is scarce. Prevention and persistence are key to managing the Eastern grey squirrel.
Eastern Grey squirrel sightings can be reported to the Invasive Species Council of BC at 1-888-WEEDSBC and to Karl Larsen who is tracking the expansion of the squirrel in the B.C. interior. The web site www.bcinvasives.ca has more information on the squirrel as well as a place to pose questions and report sightings. ■
Margaret Holm works for OSCA, the Okanagan Similkameen Conservation Alliance. For information on local wildlife and wildlife management contact outreach@osca.org or go to www.osca.org.