Voles

Voles are small, stocky, short-tailed rodents (often called meadow mice or field mice) that live in grass and ground cover and eat plants, roots and the bark of young trees. In a yard they show up as narrow surface runways in the lawn, small open holes and gnawed shrubs, and in boom years UC IPM says their numbers can soar to several thousand per acre.

Voles are often confused with moles and mice, and the ID decides which control works: mole traps, castor oil and grub killer do nothing for voles.

What are voles? Identification

• Body: compact, 4-8 inches including the tail; Penn State gives 5-7 inches for most adults.
• Tail: short, about 1-2 inches. Penn State's quick test: a mouse's tail is nearly half its body length; a vole's is much shorter.
• Head: blunt, rounded snout; small black eyes; small furred ears that barely show above the fur; chisel-shaped, often orange front teeth.
• Fur: dense, chestnut-brown to gray-brown mixed with black, gray belly. Young are uniformly gray.

House and deer mice have big ears, big eyes, pointed snouts and long tails. Shrews are smaller (a shrew fits in a tablespoon), with long pointed snouts and eyes nearly hidden in fur. A vole looks like a mouse that's been compressed. Do voles have eyes, and are voles blind? Yes they have eyes, and no, they aren't blind; unlike moles, their eyes are plainly visible.

Common US voles

ICWDM counts 23 vole species in the US, seven of which cause significant damage:

• Meadow vole (Microtus pennsylvanicus): the most widespread, across the northern two-thirds of the US (Michigan, Ohio, Indiana, Idaho, Utah and Colorado yards included). 5½-7½ inches. Lawns, fields, orchards.
• Prairie vole (Microtus ochrogaster): Great Plains and Midwest grasslands; 5-7 inches with "peppery" fur. Famous in science for pair-bonding.
• Pine or woodland vole (Microtus pinetorum): eastern US, including Georgia and much of the Southeast; 4-6 inches. Lives mostly underground, uses mole tunnels, and is the main destroyer of bulbs, hostas and roots of shrubs and fruit trees.
• Montane, California, long-tailed and Oregon voles: western states.

"Water vole" in British nature writing means a European species. The North American water vole (Microtus richardsoni) lives along mountain streams in the Northwest and rarely bothers yards.

Voles vs moles

The two often overlap: voles travel through mole tunnels and do the plant damage moles get blamed for. Penn State notes that plant damage blamed on moles is often caused by voles and mice in mole runs. If bulbs and roots are disappearing, look for voles even if you see mole ridges. For mole control see how to get rid of moles.

What do voles eat?

Mostly grasses and other green plants, plus clover, seeds, roots and tubers, flower bulbs (tulips, crocus, lilies), and vegetables such as carrots, beets, lettuce, spinach, sweet potatoes and tomatoes. In late summer and fall they store seeds, bulbs and tubers underground. In fall and winter, especially under snow, they gnaw the bark and roots of young trees and shrubs (apple and other fruit trees, arborvitae, holly, ornamentals) and can girdle them completely. They also chew drip irrigation lines.

Signs of voles in your yard

• Runways: paths about 1½ inches wide where grass is clipped to the soil, worn bare or covered with cut grass, hidden under overhanging grass. Penn State notes they're most visible in early spring, when melting snow exposes a winter of activity, and that the lawn usually recovers quickly.
• Holes: round, open, about 1½-2 inches across, connected by runways. Pine voles instead push up small cone-shaped piles of soil from underground tunnels.
• Gnawed bark: irregular tooth marks about 1/8 inch wide and 3/8 inch long at various angles, at the base of trunks, often at or below ground level or under mulch. Rabbit gnawing is larger and more uniform, with clean angled cuts on twigs.
• Plants that wilt or pull out of the ground easily because roots and bulbs are eaten. Trees with root damage grow slowly and look yellowish and weak.
• Droppings: rice-shaped, about 3/16 inch, green when fresh and turning brown or gray, in runways. Fresh clippings and green droppings mean the runway is in use; mold or roots growing in the path mean it's abandoned.

Vole biology: why they boom

• Active all the time: voles don't hibernate and are active day and night, with peaks at dawn and dusk. Are voles nocturnal? Not strictly.
• Fast breeding: gestation is about 21 days, young are weaned at 3 weeks, and females can breed at 35-40 days old. Penn State gives 1-5 litters a year in Pennsylvania; UC IPM gives 5-10 in California, with 3-6 young each.
• Short lives: most live 2-16 months.
• Small home range: usually a quarter acre or less, often a few hundred square feet.
• Cycles: populations peak every 2-6 years, unpredictably, then crash.

What eats voles? Hawks, owls, snakes, weasels, foxes, coyotes, raccoons, opossums and house cats. UC IPM warns that predators, owl boxes included, can't keep vole numbers below damaging levels around homes; predators move on to other prey and the remaining voles rebuild fast.

Are voles dangerous?

To people, rarely. UC IPM notes voles are poor climbers and usually don't enter homes, unlike mice; they may wander into garages or sheds with gaps. They bite only if picked up. Like other rodents they can carry parasites and pathogens, so handle dead voles with gloves or a plastic bag turned inside out. The real cost is to property: dead lawn strips, lost bulbs and vegetables, and young trees killed by girdling.

How to get rid of voles in the yard

1. Reduce cover. Voles avoid open ground because of predators, and Penn State calls removing weeds, ground cover and litter an excellent long-term control.

• Mow lawns and edges regularly, keeping cover at about 3-6 inches; mow tall grass around gardens, orchards and ditch banks.
• Pull mulch and vegetation at least 2 feet back from tree trunks (UC IPM suggests a 4-foot clear circle around young trees). A 3-4 inch layer of crushed stone around trunks also works.
• Clear weeds, dense ground cover, boards and brush piles near beds. Rake up matted grass in fall.
• Don't leave fallen fruit or spilled bird seed.

2. Protect plants.

• Wrap young trunks with ¼-inch hardware cloth cylinders 18-24 inches high, buried 4-6 inches, taller than expected snow depth and wide enough for a few years' growth. These also stop rabbits.
• Plant bulbs in wire baskets or with sharp gravel around them.
• Fence gardens with ¼-inch mesh or aluminum flashing at least 12 inches high, buried 6-10 inches, with a weed-free strip outside.

3. Trap. For a lawn or garden, snap traps are the tool. UC IPM's method:

• Use ordinary mouse traps, and plenty of them: at least a dozen for a small garden, 50 or more for larger areas.
• Set them at right angles across a runway with the trigger end in the path. Bait is optional; if you use it, try a peanut butter-oat mix or apple slices.
• Cover traps with a piece of gutter, a board or a box to protect birds and pets.
• Check daily. When catches stop, move traps 15-20 feet to new runways, then break up old runways with a shovel so new voles don't move in.
• Fall and late winter to early spring, before breeding peaks, are the best times.

4. Baits, with care. Zinc phosphide and anticoagulant baits are registered for voles, but Penn State notes they're restricted-use pesticides there, and UC IPM says zinc phosphide is restricted-use and only for non-residential turf, ornamentals, golf courses and parks. In practice, baiting voles is a job for a licensed applicator. Poisoned voles can kill hawks, owls and pets that eat them.

5. Repellents (capsaicin, thiram, castor oil, predator urine) have little data behind them. UC IPM calls their efficacy questionable, and they must go on before damage starts and be reapplied after rain. Use them only on plants the label allows, and never as the main control.

What doesn't work: gas cartridges (vole burrows are shallow with many open holes), ultrasonic or electromagnetic devices, and flooding, all rated ineffective by UC IPM.

What people who dealt with it say

Homeowner and lawn-care threads show a few clear patterns:

• The ID is the hardest part. Many people spend a season on mole products before realizing they have voles. Posts with photos of a "mole" often turn out to be voles or pocket gophers once someone points out the gnawing teeth.
• What fails: castor-oil granules and coyote urine come up often as first tries. Several people say castor oil did nothing for voles.
• What works: covered snap traps (mouse or rat size) baited with peanut butter, set right in the runways. People who use several traps report catches within a day or two. Others say the problem eased once they mowed shorter and stopped piling mulch thick around beds.
• Spring shock: many first notice voles when snow melts and the lawn is crisscrossed with runways. Raking out the dead grass and overseeding usually fixes it, as extension sources say.
• Mistakes: setting scissor-style mole traps for voles (wrong animal), and piping engine exhaust into holes, which is dangerous and illegal.

When to call a pro

Call a licensed pest control or wildlife operator if voles are girdling an orchard or landscape trees, you see damage over a large area, or baits are needed. For broader approaches, see rodent control.