HARD WEATHER such as we had last weekend does both good and harm in the countryside. The beneficial effects of frost are to kill off those field and garden pests that might otherwise survive the winter, and to break down lumps of soil into friable tilth. Cold also benefits predators by weakening prey species and making them sluggish. When snow lies, it renders animals such as rabbits, rats and mice more visible, and therefore easier for hawks to spot. A white blanket also has the effect of extending daylight hours, giving buzzards and kestrels - which do not operate at night - more time in which to hunt.
On the other hand, for small seed-eaters, and insect-eaters such as hedge sparrows and wrens, frost is a potential killer because the birds have a struggle to find enough food to maintain their body temperature. Frost also creates dangerous patches of black ice in little-used lanes and has a deadly, astonishingly powerful effect on field walls.
Rain, driven into a wall by wind, penetrates cracks in the stone. When the water freezes, it expands, and literally explodes the stone, shattering it into fragments and often causing whole walls to collapse in ruins.