The grey squirrel was introduced to Great Britain in the mid-19th century. There is now an estimated population of 2 million making them much more common than the native red squirrel.


Grey Squirrels and humans

Humans are the main predators of grey squirrels in Britain.  Since intentionally releasing them into the countryside in the 19th Century they have spread and flourished and now people are trying to control their numbers.  As an invasive species these squirrels  are causing many problems to other animals, trees, birds and humans.  The three greatest impacts of the grey squirrel to UK wildlife are to native red squirrels, trees, and many of our woodland birds.

Grey squirrels seem much stronger and more adaptable than our native red squirrels and have taken over many of its former territories.  This is partly because grey squirrels carry the squirrelpox virus, which is relatively harmless to greys, but which can kill red squirrels.  Also, the greys' larger size makes them the obvious winners in any physical confrontation with red squirrels.

Photo of a tawny owlForesters, gamekeepers, park keepers and many conservationists regard grey squirrels as pests, mainly because they damage trees. Young saplings (sometimes rare species) are destroyed and they gnaw the bark of hardwood trees, such as beech and sycamore, to get at the nutritious sapwood below. The raw scar left on the trunk encourages fungal attack and may lead to distorted growth.

There is growing evidence that grey squirrels are affecting native woodland bird populations.  It is thought that these foreigners are affecting birds in three ways.  Firstly by eating eggs and baby birds from the open nests of birds such as thrushes and finches and discouraging birds from using nest boxes.  Secondly, squirrels use ideal nesting spots that would usually be occupied by birds such as the tawny owl, kestrel, jackdaw, stock dove and starling.  In some areas it has been reported that squirrels can halt the breeding of tawny owls altogether by taking up these useful nesting sites.  Thirdly, they eat the same food!  Squirrels have been seen taking a bird's store of winter foods and their diet means that they are in direct competition with other birds such as the nuthatch, hawfinch and bullfinch.

In many forest areas, the grey squirrel population is controlled by trapping and shooting. Gamekeepers shoot the squirrels on private estates. It is illegal to keep, import and release grey squirrels in Britain, unless you have a special licence from the Ministry of Agriculture or Secretary of State for Scotland. The Forestry Commission and National Trust also trap and shoot grey squirrels and sometimes they put them on the menu!  Squirrels were eaten a lot in the past and now they are coming back on the menu in some places including London's top restaurants.

Although the grey squirrel is a pretty, appealing and entertaining little animal, it can be a great nuisance in a garden too, especially to a bird lover. It is very bold and soon learns to take food from bird tables and chew through baskets of peanuts. It will also destroy birds' nests to eat eggs and nestlings.

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