Over the past six months, australia has been struggling to contain a plague of mice. They're destroying crops, munching through stock piles and infesting houses. The mouse plague has caused 100 million australian dollars in damage to crops and grain stores so far. So why are things so bad? The main reason is the weather. Heavy rains have allowed grain growers to plant the largest area of winter crop ever recorded. This bumper harvest has created ideal conditions for a mass breeding season amongst the mice. And that's why this particular year has been one of the worst on record for Australia.