The most easily identifiable sign of voles is an extensive surface runway system (Figure 4) with several openings to burrows. Runways are 1 to 2 inches wide.
Vegetation near well-traveled runways may be clipped close to the ground. Feces and small pieces of vegetation are found in runways. Pine voles do not use surface runways. Instead they build an extensive system of underground tunnels. The surface runways of long-tailed voles are not as extensive as those of most other voles.
Damage to Structures
Voles invade structures only occasionally, so they present little threat to structures.
Damage to Livestock and Pets
Voles do not pose a direct threat to animals, but they consume and contaminate feed.
Damage to Landscapes
Voles can cause extensive damage to orchards, ornamentals, and plantings of trees through girdling, usually in fall and winter (Figure 5). Marks from girdling and gnawing alone are not necessarily indicative of damage by voles because other animals, such as rabbits, may cause similar damage.
Damage to trees from girdling by voles is differentiated from girdling by other animals through non-uniform gnaw marks. The marks occur at various angles and in irregular patches. Marks are about 1/8 inch wide, 3/8 inch long, and 1/16 inch or more deep. Marks made by gnawing by rabbits are larger and not distinct. Rabbits neatly clip branches at an oblique 45° angle. Examine the damage and accompanying signs (feces, tracks, and burrow systems) to identify the animal causing the damage.
Voles can damage and completely destroy field crops, such as corn, soybeans, alfalfa (Figure 6), clover, potatoes, artichokes, and sugar beets.
Runways and tunnels of voles interfere with irrigation of crops by displacing water and causing levees and dikes to wash out. Voles can ruin lawns, golf courses, and ground covers.
Health and Safety Concerns
Voles pose no major hazard to public health because of their infrequent contact with humans. They may carry diseases, such as plague (Yersinia pestis) and tularemia (Francisilla tularensis). Ectoparasites such as mites and ticks feed on voles. Use protective equipment when handling voles.