Although red squirrels forage alone, they roost in communal nests during the winter. The red squirrel constructs its nest in the branches or cavities of trees or stumps. In winter, it lives on food diligently stored up during late summer or autumn. A single cache may contain several hundred spruce or pine cones. Grey squirrels introduced to the UK have spread because they are much more suited to the changing habitat of our woodland.
Grey squirrels can thrive on acorns and a wide variety of other foods.
They also survive well in our widespread mixed deciduous woodland. So, although persecution by humans and disease has been a threat to the red squirrel, the major reason for their decline is habitat loss and fragmentation. A major decline in red squirrels occurred in England during the 1940s and 50s, corresponding to a decline in hazel crops. In southern England, red squirrels are only now found on the Isle of Wight and on three small islands in Poole Harbour. There are no grey squirrels on the Isle of Wight.