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MINKS, SHREWS AND MEN IN A WINTER SWAMP
Bil Gilbert
March 18, 1963
Smooth as water on glass, the mink flowed across the path of the three unseen amateur naturalists in the opening scene of an unforgettable experience
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March 18, 1963

Minks, Shrews And Men In A Winter Swamp

Smooth as water on glass, the mink flowed across the path of the three unseen amateur naturalists in the opening scene of an unforgettable experience

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Lee would not tell this story, except perhaps to say, "It was a good trip." He is not an abstracter, a summarizer. His restraint in this respect seems remarkable to John and me. John would tell the entire story this way: "On a winter trip to Cranesville swamp in search of the northern water shrew (Sorex palustris), Bil, Lee and the writer had the happy experience of observing several minks at play in the snow." John reasons that anyone who does not already know why three middle-aged men want to trap shrews and study the gait of minks will not profit from this story, no matter how much explanation is made.

There remains my way. I am forever seeking the general significance of such things as shrews and minks and frozen swamps. Shrews as an order are perhaps the commonest mammals in North America, but paradoxically they are also among the least known. Shrews are very small, the smallest of our mammals. They move quickly and secretively under leaves, rocks and logs. In a gross way, from a distance, shrews look like young mice. A great many people have never looked carefully enough to see a shrew. Others who have seen shrews do not know what they have seen. Often when John, Lee and I ask permission to set out our traps on private land we are told, "Go ahead. But shrews—there's nothing like that around here." We take satisfaction in returning and showing our catch to this kind. In the same way, one point of this story is to note a very fine specimen of euphoria, not because it is uncommon but because it is so much commoner than generally believed.

John (a senior research scientist at a well-known university), Lee (an engineer in charge of the technical services of a trade association) and (euphemistically, a communicator) have been amateur mammalogists for a long time. We have studied shrews for years. Currently we want to live-trap a northern water shrew in the Cranesville swamp, which straddles the West Virginia-Maryland state line.

As shrews go, the northern water shrew is large, about six inches long, including the tail. It is handsomely marked, black above with silvery underparts. Water shrews are found along streams, shallow lakes and marshes, where they hunt minnows, amphibians, insects and other small aquatic creatures. These shrews are good swimmers, a fringe of stiff hairs growing between the hind toes giving them in effect a webbed foot. In conformation and habits they suggest a diminutive otter. Though relatively abundant in the northern and western parts of the U.S., water shrews are rare and have been found in only a few scattered locations south of the Adirondacks. The Cranesville swamp is one of the most southerly places in which they have been collected. Two have been taken there, the last almost 20 years ago. We go to Cranesville because it is the only place within weekend driving distance of our homes where we have any reason to think we might trap a water shrew. Also another record—a current one—of this species in the swamp would be significant.

Water shrews aside, the Cranesville swamp is a remarkably interesting place for naturalists. It is a few miles west of the Youghiogheny River, a high swamp some 2,000 feet in elevation, lying on a plateau in the Allegheny Front. The swamp is a frost bowl, i.e., a shallow depression into which cold air flows down the sides and toward the center. Evidence of this action can be seen in the early fall when low vegetation in the middle of the swamp is browned by frost while the plants around the rim of the bowl are still green.

This high, cold swamp forms an isolated biological niche that supports some animals and plants that are distinctly northern and are curiosities in the southern highlands. Besides the water shrew, snowshoe hares, woodland jumping mice, certain fish and amphibians are found here, south of their normal range. Tamarack and black spruce, both northern trees, grow in the swamp as do sundew and northern gentians. There are patches of sphagnum moss interlaced with cranberry bushes.

Despite the northern oddities, the dominant swamp growth is typical of the region. White pine, hemlocks and red spruce grow around the swamp and on islands within it. Rhododendron and alder are the principal low cover. The underbrush is laced through with tough green briars. There are many small, cold, black streams rising, sinking, flowing erratically through the swamp. There are occasional cattail swales and patches of open water but, in the main, Cranesville is a dense, muddy thicket. (The wildest, most interesting part of the swamp, a 200-acre tract, has been purchased and set aside as a sanctuary by Nature Conservancy, an effective private conservation group.)

On our first summer trip it took us nearly an hour to flounder and crawl half a mile from the nearest road to a big beaver pond at the center of the swamp. We trapped along the pond for no better reason than that the Indians called the water shrew "beaver mouse" because it was so often seen about dams and lodges. After the first hard summer trip into the swamp, Lee, our logistical expert, suggested that we try it in the winter on snowshoes. It would be easier packing our traps in over the snow than through the thickets. We might find shrew signs in the snow. Animals often come more readily to trap baits in the winter when natural food is scarce.

When we returned in early March there was a two-foot snow cover on the swamp, but it was not cold for these parts. The snow was melting in the full sun. As Lee had predicted (Lee is the kind who carries a waterproof map case, can always bring out the right topographic sheet and unroll it right side up on the first try), the going was easier than it had been in the summer—easier but not easy. We could walk over many of the thickets through which we had crawled in August. However, tough, gnarled rhododendron stobs are admirably shaped to catch the webbing of snowshoes and trip a snowshoer. Also, because of the thaw and the moving water in the swamp, the ice was rotten in spots. Each of us had the experience of stepping on what appeared to be solid, snow-covered ice and then breaking through into black swamp water and muck.

We proceeded carefully, lifting our shoes and waving them gingerly ahead of us like pedal antennae. Once down the brushy rim of the swamp, we picked up the main outlet from the beaver pond. The straight, narrow channel was mostly frozen and made a good trail. We set the traps in chinks in the dam and lodge, under windfalls and by open water, wherever it seemed to us we would be if we were water shrews. In several places we found very small mammal tracks and once a single, twisted scat. However, small tracks blur quickly in wet snow, and shrew scatology is an esoteric business. We did not know that shrews had made these signs—deer mice and voles were other possibilities—but we did not know that they hadn't, so we trapped these obscure trails.

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