Mus Musculus and Apodemus Sylvaticus
Generally speaking there are two species of mice which enter houses in the UK. These are the house mouse and wood mouse.
House mice originated in Asia but have since spread throughout the world. Along with brown rats, they are considered to be the most widespread terrestrial mammal other than humans. In modern warm houses and with a supply of food available, house mice can breed all year round. Wood mice only move indoors in autumn and winter time to escape the cold weather.
Both species mice need 3 grams (about 1/8th ounce) of food per day to survive and provided there is moisture in the food mice can manage without needing further liquids. Despite popular belief, their favourite food is not cheese, but grains and cereal products, so the larder of a modern house, with packets of breakfast cereals is ideal. For variety, mice will nibble at anything else available, including fruit and vegetables. As their sense of taste is not as keenly developed as that of humans they can survive on items which surprise us such as soap, candles, or almost anything that has some trace of fat or nutrition. The ability to survive on tiny amounts of food and the fast breeding rate mean that mouse infestations develop quickly. By the time you see a mouse running across the floor it is very likely that the infestation includes not just the mouse you see, but all its relatives.
The signs of a mouse infestation are the damage caused during feeding -loose foods such as sugar scattered in cupboards and food packages nibbled round the edges. Mouse droppings are black, and about the size of a grain of rice. They will be scattered everywhere that mice roam, but particularly in corners of cupboards or around food packages. Although mice eat only small amounts of food each day, they tend to nibble and urinate liberally. Most of the damage caused by mice is due to the contamination of food.
If you have evidence of mice in your kitchen cupboard, check all food packages carefully: discard all open packets and any packets that show signs of damage and transfer new food out of paper and cardboard packaging into mouse proof containers. Glass jars with screw lids or heavy plastic containers with strong snap on lids are ideal.
Mouse traps can be effective, but unless you have just one or two mice they will not clear an infestation. The average domestic cat is generally not effective at eradicating infestations. It may catch, play with, and kill single mice, but it is only a game. The best way to control mice is to use poisons which have been specifically designed for the purpose. Once poison is laid and consumed, mice will start to die quickly. There is a risk that if a mouse dies in an inaccessible location under the floor or behind built in furniture there may be a smell. Where safe and practical to do so attempt to remove the body, but if this cannot be done without damage to your house, the smell will go away in about a week, and during this time it can be masked with an air freshener.