The grey squirrel has adapted from the mixed broadleaved woodlands of North America to our lowland mixed broadleaf woodlands, which provide an abundant, diverse diet but, importantly, which have no natural predators other than foxes. However, there is growing evidence that when pine marten populations increase, those of grey squirrels decrease. They are equally at home in large woodlands, parks, farmland, suburban or even urban areas.
Grey squirrels do not thrive in purely coniferous habitats, needing to retain their weight throughout the winter which is not possible on a diet of cones.