Although moles are very common in Western Washington, they are rarely seen due to their subterranean lifestyle. But you usually know when they're around. As moles excavate and maintain their underground burrow systems, excess soil is pushed to the surface forming molehills.
Two species—the Townsend's Mole and the Coast or Pacific Mole—are responsible for building the molehills in Washington State. A third species, the Shrew Mole, does not build extensive burrow systems, but spends time on the soil surface or under leaf litter.
Moles are highly specialized digging machines. They have broad, shovel-like forelimbs that allow them to power through soil. Although those who maintain gardens or lawns often view moles negatively, the burrowing is actually beneficial. It aerates and mixes soil layers and improves drainage. In addition, moles feed primarily on invertebrates, including the insect larvae, such as Crane Flies, which damage roots.
Moles are generally solitary, and aggressively defend their burrow systems. Mating season, in January and February, is an exception, when males will seek out females. Females give birth about 4 to 6 weeks after mating. Young moles spend 30 to 36 days with their mothers before dispersing to find their own territories. When they disperse, the young moles usually move above ground at night where many fall prey to owls, coyotes and other nocturnal predators.
Most conflict situations have to do with the molehills. Moles do sometimes harm plants, although inadvertently, by uprooting or covering them up as they diligently excavate. Moles do occasionally eat plant matter such as roots, tubers and bulbs. The presence of moles, however, is likely to be more helpful than harmful to the health of the soil on your property.
Excluding moles from your entire yard is difficult, but there are ways to prevent them from gaining access to your flower or vegetable gardens.
Above: A Townsend's Mole in care at PAWS Wildlife Center