On Jan. 7 we woke to almost a foot of snow and the first good dump of the white stuff of the new year. My week kept me busy with no time to walk around our property in the snow until Jan. 14. By then most of the deep snow had melted, leaving the backyard and fields with only an inch or two and the shaded corners and woods with more.

I discovered two sets of fresh deer tracks in the yard coming from over the wall between the yard and pasture. I crossed the wall and followed the tracks through the field and into the woodlot at the south end of the field. I also found tracks of a squirrel who had dropped from a tree at the edge of the field and had been digging among the grass for its buried treasure of acorns cached in the fall. But what caught my eye was a series of melting tunnels, only an inch or two in diameter that crisscrossed in the snow-covered field just above the wet grass.

Just as tracks on freshly fallen snow reveals the habits and whereabouts of our wildlife neighbors, tracks and tunnels below the snow also provide a unique glimpse into the life and winter survival of lesser known, but still important animals. In our region there are a few rodents able to survive the cold season by living within grassy tunnels in the “subnivean” zone between grass and snow.

“The word subnivean comes from Latin “sub” (under) and “nives” (snow). Mice, voles, and shrews retreat here for protection from cold temperatures, bitter winds and hungry predators. Under the snow, these tiny mammals create long tunnel systems complete with air shafts to the surface above,” wrote Barbara Mackay in “Subvniviean Zone: Shelter in the Snow,” from The Outside Story, volume two.

Meadow voles created the tunnels in our back field, and though infrequently seen by us, voles are a critical part of the ecosystem. These cute little rodents are a food source for many animals including fox, coyote and bobcat. The Stokes Guide to Nature in Winter lists voles as the most important food source for birds of prey and many carnivorous mammals. According to Stokes, 95 percent of our eastern hawks’ and owls’ winter diet consists of the meadow vole.

Here are some interesting facts I uncovered about voles.

• Voles are small rodents and very common to our region. There are two species found here, the meadow vole and the woodland vole, though it is the meadow vole that is the most abundant.
• Voles are up to 6 ½ inches in length (including the tail) stocky in appearance with a short snout, small inconspicuous ears, brownish fur on their bodies and lighter on the undersides with tail of 1 to 2 ½ inches in length. Meadow voles have more color variation than the woodland variety and are also larger, weighing from ½ to 2 ½
• Meadow voles can be found throughout the northern third of the United States and up through Canada. The woodland vole is found throughout the eastern U.S. Meadow voles inhabit open areas, like my back field, as well as yards and marshes, while woodland voles prefer woods and forest.
• Voles create shallow tunnel systems. The meadow vole creates passages and runways on the surface through thick grass and cover. They can nest in underground chambers but may also make nests on the surface under cover of vegetation during the summer.
• Primarily herbivores, voles rely on grass, clover, roots, tubers and flowers. They also eat the bark of fruit trees and can cause serious damage in orchards by eating the inner bark, or phloem, impeding the flow of sap and nutrients to the tree. They will occasionally eat insects or small invertebrates.
• As a primary food source for most carnivores, voles evolved to reproduce in significant numbers each year. In our region, meadow voles can produce 5-12 litters a year. They have the highest reproductive rate of any mammal, with females able to breed as young as one month old.

If you see a fox, bobcat or coyote in your yard, or a bird of prey perched above a field, there is a good chance a vole is on the dinner menu. Nature has provided our carnivorous mammals and birds with an abundant food source in the meadow vole, making them an important link within the ecosystem and relied on by many of our region’s wildlife.

You never know what you might find in your own backyard, even in the snow and cold of winter. We live in a beautiful place called The Last Green Valley National Heritage Corridor. I hope you’ll join us as we explore our region, care for it, enjoy it and pass it on.

Information for this column was sourced from The Outside Story, volume 2 published by Northern Woodlands, The Stokes Guide to Nature in Winter, The Kaufman Field Guide to Nature in New England, and the website Wildlifeofct.com.

Bill Reid is the Chief Ranger of The Last Green Valley National Heritage Corridor and can be reached at 860-774-3300 or bill@tlgv.org