CAMERON, W.Va. -- If you've ever spooked a cottontail in an old field, you probably watched it zig and zag, and then suddenly seem to disappear into thin air. More likely it dashed into the safety of a brush pile.

When cabin fever strikes next month, get outside on a mild winter day and build a brush pile for wildlife. It's easy, and it provides valuable habitat to a variety of wildlife including everything from mice and chipmunks to snakes, skunks, and many songbirds.

The best place to build a brush pile is on the edge of a wooded area. And they should be placed as far away from houses as possible because some of the species attracted to brush piles can be backyard pests.

Begin a brush pile by laying a foundation of large rocks, concrete blocks, old tires, plastic pipes of various diameters, and/or pieces of downspouts to provide refuge for a variety of species. This base layer elevates the first course of logs above the ground so they rot more slowly. It also creates a maze of escape lanes for a variety of small mammals.

The next step is to place two or three alternating layers of logs or old fence posts, four to six inches in diameter, perpendicular to each other.

Now the foundation is ready for the brush, which can include small trees, broken branches, and at this time of year, used Christmas trees. Most people are happy to donate used Christmas trees to wildlife projects. If you use several conifers, tie them together so they don't scatter in the wind.

Though a backyard brush pile might measure 8 feet in diameter and 4 to 5 feet high, if you live in a rural area, more and bigger brush piles are better and will attract more wildlife. On state wildlife management areas, for example, brush piles can stand 10 to 12 feet high and be 20 to 30 feet long.

A well-constructed brush pile should last five or six years, though over time it will collapse under its own weight. To extend the life of the pile add to it every year as materials become available. When the pile becomes simply a mass of organic matter, build a new one right next to the old one. If you live in a rural area and have access to some acreage, build a series of brush piles about 20 yards apart to create even more habitat.

The success of a brush pile can be evaluated by simple observation. After a significant snowfall, which makes brush piles look like igloos, watch them whenever possible. When predators patrol the area, you'll see birds and mammals dash inside to escape danger.

In the morning shortly after daybreak, watch for birds leaving the brush pile. The blanket of snow that covers the pile provides insulation from frigid night air and makes it an ideal roosting site. In late afternoon, watch as these same birds return to the protection of the brush pile to roost. Birds that roost in brush piles include song sparrows, house finches, juncos, white-throated sparrows, and towhees.

The best way to evaluate how mammals use a brush pile is to inspect the perimeter each morning, especially after a snow. Look for tracks of everything from small mammals such as shrews, deer mice, and weasels to skunks, raccoons and opossums.

A trip to the local library should yield some excellent guides to tracking, including "Field Guide to Tracking Animals in Snow" by Louise Forrest and Denise Casey (1988, Stackpole Books, $19.95), "Tracking and the Art of Seeing: How to Read Animal Tracks and Sign" by Paul Rezendes (1999, Collins, $25), and "Mammal Tracks & Sign: A Guide to North American Species" by Mark Elbroch (2003, Stackpole Books. $46.95). Used copies at discounted prices are available at www.amazon.com.

Send questions and comments to Dr. Scott Shalaway, 2222 Fish Ridge Road, Cameron, WV 26033 or by email at sshala...@aol.com