At times when mice or vole populations are high, it can be difficult to make much impression on their numbers. Fortunately these rodents do not sustain high populations for long and their numbers will drop back to normal low levels.
Where possible tolerate or use barriers and contained storage to deter damage from these animals as all methods of control involve killing them. RSPCA advice on living with mice cab be found here
Fitting young or newly planted trees with tree spirals (biodegradable spirals based on potato starch are available) can help reduce damage to bark.
Trapping can be effective for mice in a garden situation, although voles can be harder to control. Break-back traps of the type used against house mice can be effective when set in places where damage is occurring. Pieces of carrot or dessert apple are effective baits for voles, and peanut butter for mice. When using traps or baits out of doors, they should be placed under covers to reduce the risk of other animals interfering with them. Birds are particularly vulnerable to accidental trapping.
Non-lethal traps are available but these must be checked at least twice a day, to comply with animal welfare legislation, and the rodent released some distance (several miles is usually recommended) from the trapping site. These animals suffer high levels of stress in the traps, during transportation and tsurviva rates once released are unknown.
Poison baits can be used against field mice and voles but may not be very effective during spring-autumn when there are plenty of alternative food items available. Only baits approved for outdoor use can be used in gardens, and every care (by following the manufacturer's instructions closely) must be taken to avoid non-target species consuming the bait. Baits approved for indoor use can be used in sheds and greenhouses, but again great care should be taken. Accidental poisoning of non-target animals is illegal.
Dead animals should be disposed of by burying them or placing the corpses in a polythene bag and disposed of in refuse collection. Always wear rubber gloves when handling traps, bait or dead rodents.