ON THE BACK: Harvest mice are the smallest rodent in Europe, weighing in at less than a 2p coin. They can live for up to 18 months. Being small and light and aided by their prehensile tail, harvest mice can move quickly through the undergrowth. They can be found in a variety of habitats which include cornfields, hedgerows, long grass, bramble patches and reed-beds. Looking for their woven nests and analysing barn owl pellets for their remains are used to survey for these elusive rodents.