The mole (Talpa europaea) is found throughout Britain but not in Ireland. They are present in most habitats where the soil is deep enough to allow tunnelling but are uncommon in coniferous forests, on moorlands and in sand dunes, probably because their prey is scarce.
Moles spend most of their lives underground in a system of permanent and semi-permanent tunnels. Surface tunnels are usually short-lived and occur in newly cultivated fields, in areas of light sandy soil and in very shallow soils, where prey is concentrated just below the surface. More usual is a system of permanent deep burrows which form a complex network often hundreds of metres long at varying depths in the soil. The deepest tunnels are used most in times of drought and low temperatures. Permanent tunnels are used repeatedly for feeding over long periods of time, sometimes by several generations of moles. Within the tunnel system moles construct one or more spherical nest chambers, each lined with a ball of dry plant material. Nests are used for sleeping and for raising young.
Earthworms are the most important component of the moles diet; an 80g mole needs around 50g of earthworms per day. Moles also eat many insect larvae particularly in the summer. Earthworms dominate the winter diet; the moles sometimes collecting and storing them alive in spherical chambers. The stored worms are immobilised by a bite to the head segment. Food is either actively dug out of the soil by the mole or more often collected from the floor of the tunnel. Many soil animals fall through into the tunnels. Moles occasionally forage on the surface particularly during times of drought.
Males and females are solitary for most of the year, occupying exclusive territories. With the start of the breeding season males enlarge their territories, tunnelling over large areas in search of females. A litter of 3 or 4 naked babies is born in the spring. Fur starts to grow at 14 days, eyes open at 22 days and they are weaned at 4-5 weeks. The young start to leave the nest at 33 days and disperse from their mother’s range at 5-6 weeks. Dispersal takes place above ground and is a time of great danger. Moles are sexually mature in the spring following birth.
The mole uses its fore limbs to dig, shearing soil from the sides of the tunnel with alternate strokes. Hind limbs are used to brace the mole’s body against the tunnel walls. The mole turns round, scoops up accumulated soil with its fore limbs and pushes it along a previously dug side tunnel leading to the surface. The soil is pushed out above the ground to form a molehill.
Most moles don’t live beyond 3 years but can live up to 6 years. Their main predators are owls, buzzards, stoats, cats and dogs but vehicles and humans also kill many. They have no legal protection in Britain and are frequently regarded as pests by farmers, horticulturists and green-keepers. Surface tunnelling in newly planted fields may disturb plant roots so much that they will wilt and die. Mole hills cause damage to farm machinery. Mole hills also cause contamination of grass used to make silage. Despite their nuisance status moles can be beneficial to man, preying on many harmful insect larvae such as cockchafers and carrot fly, while tunnels help drain and aerate heavy soils. At the beginning of the century moles were trapped in large numbers for their pelts but today they are killed as pests. Where control measures can be justified, there are two main methods, trapping and poisoning with aluminium phosphide. Strychnine hydrochloride can no longer be purchased or used for mole control in the UK. The approval for this product expired on 31 August 2006.