The eastern gray squirrel (Sciurus carolinensis), also known, particularly outside of North America, as simply the grey squirrel, is a 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.
One of our most familiar mammals, the grey squirrel can be found in woods, gardens and parks across town and country, and often proves to be very tame. It is a frequent visitor to gardens with bird tables and feeders. Grey squirrels feast on hazelnuts by cracking the shell in half. You may also find pine cones that have been nibbled, leaving what looks like an apple core behind. They will cache their food in autumn if it is abundant. Grey squirrels make a rough nest, called a 'drey' out of twigs, leaves and strips of bark in the fork of a branch, high up in the tree canopy. Females may have two litters of three to four young a year.
The grey squirrel has a silver-grey coat, with a brownish face and feet, and pale underside. It has a characteristically bushy tail. It is distinguished from the red squirrel by its larger size, grey fur, and smaller ears without tufts. However, grey squirrels can vary in colour, with some appearing slightly ginger. Grey squirrels are renowned for their agility, adept climbing and cunning - they can crack open bird feeders and run along tight-rope washing lines to get at their nutty prize.