Underneath our gardens, woods and meadows is a secret world of tunnels carved by moles, voles, shrews, groundhogs, chipmunks and other burrowing animals.
Some are simple pathways from here to there. Others are sophisticated networks that combine roadways, nesting rooms and food storage areas. They are hidden on purpose, but there are telltale clues.
For moles, tunnels are food delivery mechanisms. As they dig, moles shake loose insects, spiders and worms. Moles live most of their lives underground, so you do not see them often, but you can look for low ridges or dirt mounds they have pushed up from below. Sometimes their tunnels rip up the lawn.
Moles do not eat plants, but people think they do. "Moles get blamed a lot for vole damage," says Fairfax County extension agent Adria Bordas.
Voles, admittedly, are hard to love. Pine voles, which burrow through leaf mold and mulch, can eat their own body weight in 24 hours. They like to gnaw roots, and sometimes the first sign they are around is that your shrub or ornamental tree keels over. Mouse-sized, but with stubbier faces, they have five or six litters a year. Sometimes you can see a small hole next to a tasty plant, tracks in the winter snow or small animals darting about.
Bordas gets lot of calls about getting rid of voles and offers advice about trapping. For people who want to discourage voles from settling in, she suggests not planting species they like to eat. If you do, throw some sharp-edged rocks into the planting hole. And do not pile mulch more than two inches high.
Craig Tufts, chief naturalist for the National Wildlife Federation, adds the following: Do not let birdseed from your feeder fall on the ground. Voles love that. Rats, too.
(There also is a meadow vole that nests aboveground and uses runways under matted leaves or grass.)
At the other end of the likeability spectrum are chipmunks, which live in burrows under logs or rocks or in other protected places with trees nearby. They have a widely varied diet that includes nuts, acorns, seeds, mushrooms, berries, corn, insects, bird eggs and small invertebrates.
Chipmunks are responsible for some garden surprises because they bury food with the intention of unearthing it later. "Crocus and sunflowers can end up in the oddest places," Tufts says, "because chipmunks store food and forget about it."
The burrowing animal that helps others the most, Tufts said, is the groundhog, sometimes called a woodchuck. He calls them "woodpeckers of the earth" because they excavate summer and winter dens that they often later abandon, providing free housing or escape routes for other animals.
Like other tunnelers, they aerate the earth as they dig and expose dormant seeds to the sun, allowing them to grow. You might see a 6- to 10-inch-diameter entrance hole to their den, but groundhogs also build a secret entrance. Their burrows can be several feet deep and up to 30 feet long.
"As long as they are not trashing your vegetable garden, they are a pretty interesting animal to watch," Tufts says. "And when you think of what they do in churning soil over and producing den sites, you realize they are a pretty significant critter in our area."
Also among the burrowers is the tiny shrew, which makes tunnels through loose surface dirt, preferably in a damp area. Sometimes, when an outdoor cat brings back a small animal, it is a shrew (or vole), not a mouse.
Shrews, which are active year-round, are extremely nervous animals. They do not let themselves be seen often, but they are very noisy, with a sound that Tufts describes as a high-pitched rapid chitter, somewhat like a bat's.
Easily shocked, they can die of fright from hearing a thunderclap. So when you hear the boom of fireworks tonight, think of the tiny shrew, shivering in its burrow.
-- D'Vera Cohn