Red squirrels build nests, called dreys – and they will sometimes share dreys to keep warm during cold winter months.
Nobody’s sure how many red squirrels there are, but it’s thought they’re decreasing. Both habitat loss and the introduction of the grey squirrel are the main threats to the red squirrel. Grey squirrels have replaced their red-haired cousins in much of Britain as they’re stronger and they carry a virus that only affects red squirrels.