Squirrels are rodents. They live mainly in trees, but they frequently come down to the ground in search of fallen nuts. In summer the coats of grey squirrels turn reddish, and sometimes people mistake them for red squirrels, the original native squirrels of Britain and Europe.
Grey squirrel (summer coat)
Grey squirrels are now far more plentiful than red squirrels - indeed, since their introduction from North America, grey squirrels (Sciurus carolinensis) have replaced red squirrels in many parts of the British Isles. Fortunately there are still a few strongholds of red squirrels - notably on Anglesey, the Isle of Wight, Cumbria, Ireland and Scotland.
Grey squirrels have an unfortunate tendency to damage trees by stripping them of their bark. Once the bark has been removed all the way round a tree, it must almost surely die.
Squirrels also help to propagate trees, as they bury caches of nuts underground. Whenever they fail to recover these stores, some of the nuts may germinate and then new trees can arise.
Grey squirrel (winter coat)
A squirrel's nest, which is usually in a tree, is called a drey; it is where the young squirrels are looked after for the first two months of their lives. A typical litter would be between three and five youngsters.