The Muridae family.

Part three the harvest mouse.

One of the worlds smallest rodents, the harvest mouse weighs less than a 2p coin. Because it is so tiny it can climb fast and confidently among thin stalks. As their name implies, harvest mice have always been associated with corfields, but now that these are reaped by machines and then ploughed up, it is difficult for them to live their permanently. They more often live in the long grass at the base of a hedge, invading the growing corn crop in early summer so that they can nest and feed. Tall vegetation such as brambles and rushes is, however, their main summer home, and they are common in reed beds despite the water below. Their peak breeding season is between August and September. When young harvest mice become independent at about 16 days old they are grey-brown, they later moult to their adult colouring. Although harvest mice are threatened by urban development and modern day farming methods such as stubble burning and scrub and hedge removal,( to be fair to farmers they are putting some hedge rows back in to their estates) they may be able to benefit from the huge, motorway embankments. Because they are active by day and night, the mice are likely to be caught by both daytime and nighttime predators, because of this threat most harvest mice only live for a couple of months. The harvest mice has a blunt nose, small ears and yellow-brown fur, they are very agile, this is important because they use their tail as a fifth limb to grasp stalks as they are moving around. They are about two and a half inches in length with their tail being about the same size in length. They are quite widely spread in coarse vegetation and hedgerows, but are not found on higher ground. Their nest is a tennis ball shape fixed about eighteen inches off the ground, they are normally built in grass or reeds. They are about two and a half inches across , the framework is woven from neatly shredded living leaf blades, so the nest hangs between stems. Seeds, grains, grass shoots and soft fruit, as well as insects such as weevils, are all part of the the harvest mouses diet. Because the harvest mouse is very active, it has a large appeteite for its size. There are usually from three to eight young in a litter, born onto a layer of chewed grass leaves. Females are pregnant for 17-19 days and may have three litters in a year, each one in a new nest. When tall plant stems die back in Autumn, the harvest mice are left exposed and seek cover in low vegetation or sometimes in barns . Many mice die during winter, but for the surviving mice their coat is darker so they can blend in better to their surroundings. They build a winter nest which is low, usually in a clump of grass or under a hedge.