SGL#166 Beaverdam Wetland

On a rainy Sunday afternoon in early October, my husband Bruce and I joined fellow members of our Juniata Valley Audubon Society on a field trip to SGL#166.

George Mahon, a member of the Juniata Valley Audubon Society, in the Beaverdam area

George Mahon, a member of the Juniata Valley Audubon Society, in the Beaverdam area (Photo by Bruce Bonta)

This 11,776-acre game land includes the Beaverdam Wetland Biological Diversity Area (BDA), which is tucked in a remote wooded valley in southern Blair County between Canoe and Brush mountains and forms the headwaters of Canoe Creek. And it lives up to its name because beavers still occupy the creek and wetlands.

Since Beaverdam Road is only open during big game seasons to a parking lot four miles from the game land’s southern boundary, we had a reasonably short hike on the gravel road to reach the Beaverdam area.

The rain stopped when we started off through a diverse upland hardwood forest that includes such trees as American basswood, sugar maple, and white oak, as well as limestone-loving yellow or chinquapin oak and the thicket-forming shrub or small tree American bladdernut that favors moist, floodplain forests and stream banks.

A winterberry growing along the trail

A winterberry growing along the road (Photo by Bruce Bonta)

From the road I saw invasive stiltgrass and garlic mustard and occasionally a fern understory, but according to the Beaverdam Wetland BDA report, this forest also contains the usual invasive multiflora rose, Japanese barberry, and European privet as well as the native spicebush and black haw shrubs. We also stopped to admire a young American chestnut tree, a patch of partridgeberry and a winterberry, covered with red berries.

The BDA report lists a wide variety of spring wildflowers in the forest such as blue cohosh, wild ginger, jack-in-the-pulpit, mayapples, false Solomon’s seal, yellow fairy bells, and sweet cicely.

We were in, what I later learned from Justin Vreeland, Regional Wildlife Management Supervisor for the Southcentral Region of the Pennsylvania Game Commission, is the Canoe Creek Old Forest Unit (OFU), a 3,922-acre portion of the game land managed for late-successional forest attributes.

A view of Canoe Creek in the Canoe Creek State Park, downstream from the Old Forest Unit

A view of Canoe Creek in the Canoe Creek State Park, downstream from the Old Forest Unit (Photo by David Brossard in Wikimedia, Creative Commons license)

In addition to protecting the Canoe Creek riparian zone, it is hoped that this contiguous tract of mature hardwood forest will attract many forest-interior and riparian birds of conservation interest including Acadian flycatchers, blackburnian, black-throated green, black-throated blue, worm-eating, Kentucky and cerulean warblers, Louisiana waterthrushes, red-shouldered and broad-winged hawks, scarlet tanagers, wood thrushes, and yellow-throated vireos.

During our visit our bird list was meager—gray catbird, blue jay, eastern towhee, field sparrow and ruby-crowned kinglet—due to the weather and because most of the previously mentioned forest birds were already on their way south for the winter.

The beaver pond in the wetland area

The beaver pond in the wetland area (Photo by Bruce Bonta)

Once we reached the wetland complex with beaver ponds on either side of the road, the trees and shrubs changed to what the BDA report describes as “a mosaic of graminoid [grassy] meadow, shrubland and palustrine [wetland] forest communities.” The BDA report adds that “the floodplain holds an especially interesting palustrine woodland with a high diversity of plant species,” such as poison sumac, royal, interrupted and marsh ferns, white turtlehead, yellow marsh marigold, five sedge and two grass species.

We saw the shrub buttonbush and the vine virgin’s-bower, both wetland species, as well as thickets of alder. The bark of the latter is sometimes eaten by beavers, although they prefer aspens above all, followed to a lesser degree by willows, but they will eat the bark of other tree species if neither aspen nor willow are available. In spring and summer months, they switch to non-woody vegetation especially grasses and aquatic plants.

For instance, a study in Mississippi found in the stomachs of beavers material from 42 tree species, 36 genera of green plants, four kinds of woody vines and a lump of grasses, according to Ben Goldfarb in his engaging book Eager, the Surprising Secret Life of Beaver and Why They Matter. He writes that “beavers are among our closest ecological and technological kin” because both humans and beavers are “wildly creative tool users who settle near water, share a fondness for elaborate infrastructure, and favor fertile valley bottoms carved by low-gradient rivers.”

Before Europeans arrived in North America, researchers calculated that the continent had between 15 and 250 million beaver ponds. “The Lehigh River,” Goldfarb writes, was “almost choked with beaver dams, which helped form the ‘Great Swamp’ at its headwaters…” Beavers still change the landscape and by doing that create prime songbird habitat.

A beaver dam

A beaver dam (Photo by Tom Gill on Flickr, Creative Commons license)

In another study in coastal Maryland back in 2000, researchers found that a single beaver pond slashed the discharge of total nitrogen by 18%, phosphorus by 21%, and total suspended solids—waterborne particles classified as a pollutant by the Clean Water Act—by 27%.

These clever engineers build their dams for safety from predators—black bears and coyotes in our area—shelter from weather, and food storage. Propelled in water by their webbed feet, they can hold their breath for 15 minutes, have transparent eyelids that allow them to see underwater, and a second set of fur-lined lips behind their upper and lower chisel-shaped teeth, that enable them to chew and drag wood without drowning.

Beaver fur consists of two-inch-long coarse guard hairs over a soft, thick, buoyant and waterproof underfur. A Scrabble-letter-sized patch of it has as much as 126,000 individual hairs, more than we have on our heads. Their flat, scaly tails are rudders and alarm systems and they have a net of tightly meshed blood vessels that can regulate their temperature.

A beaver at work

A beaver at work (Photo by Tim Lumley on Flickr, Creative Commons license)

They fell trees by balancing on their back legs with their tails beneath their bodies, and use their large teeth to chip away at the trunk until the tree falls. Then they gnaw off the branches and cut the trunk into manageable pieces before hauling them off to their building site. Researchers report that 62% of the trees beavers cut fall in the direction of the dam they are building. They peel their lodge or dam sticks and eat the inner bark before weaving them into their constructions.

The dams they build can be as small as a couple feet to half-mile-long dikes. A family unit of between four and ten consisting of mating adults, newborn kits, and yearlings can build and keep up more than 12 dams and change a narrow stream into a broad chain of ponds. They also construct burrows and lodges where they sleep, raise kits and winter. Since they don’t hibernate the adults spend the winter dragging sticks and roots from their submerged larder to feed their family.

Needless to say, we didn’t see any beavers during our field trip. Vreeland hopes to develop higher-quality beaver habitat along Canoe Creek by planting aspens.

The Canoe Furnace used trees from the Canoe Valley as fuel

The Canoe Furnace used trees from the Canoe Valley as fuel (Photo in the Penn State Special Collections in Flickr, Creative Commons license)

There have always been beavers in this valley, although trees were first cut as early as 1807-1809 and into the 1870s to fuel Canoe and Etna iron furnaces. A lumber railroad operated in the upper Canoe Creek watershed and mining railroads along the southern ridge.

Since that time, at least one lumber company early in the twentieth century “turned [the valley] from a splendid forest to a desert waste,” according to outdoor writer and hunter, Harry P. Hays, who frequented the valley then. He also visited Margaret Aurandt, whose grandfather, John Hancuff, was the first settler in the valley in the early nineteenth century.

Aurandt was born in 1866 and lived in the valley most of her life, the last 17 years—from 1912 to 1929— alone and on her own, “her friends the trees, birds, flowers, animals, and other things of the forest. Her home stood at the edge of a magnificent stand of white pine trees, where the mid-day sun could only send scattered shafts of gold.” The logging “was a great blow to the lonely woman, who grieved deeply, and was bereft of much of the former joy of her woodland life,” Hays writes.

One hundred years have passed since the logging occurred. I think Aurandt would be pleased to learn of the establishment of the Canoe Creek Old Forest Unit, which Vreeland hopes will benefit many mature-forest-dependent species including a wide variety of birds such as northern goshawks, wild turkeys, and winter wrens, as well as mammals—fishers, silver-haired bats, white-tailed deer, black bears, gray and southern flying squirrels.

Furthermore, according to the comprehensive management plan for the OFU (shared by Mr. Vreeland), officials want to “promote late-successional forest conditions on higher quality soils.” Such forests “are rare because these historically were converted to agricultural land uses or subject to multiple timber harvests.” For this reason, large parts of the OFU are on good growing sites for both hardwood and conifer forests. The plan also calls for providing “an extensive area of unfragmented forest,” although it is now bisected by the game land’s road and a 100-meter-wide electric right-of-way corridor.

Still, the OFU is unique in southcentral Pennsylvania, and Vreeland says in an email, “I firmly believe if we are to conserve wildlife diversity, we need to maintain forests, to include areas largely left to nature’s processes, on an array of soil types, including productive ones, because these will produce different structural and compositional characteristics than a similarly aged forest on poorer soils.”

 

Visitors from the River

Occasionally we are reminded that the Little Juniata River flows past the northeast end of our mountain when unexpected visitors from the river appear here.

Imagine, for instance, my husband Bruce’s surprise when driving down our narrow, gravel, wooded, hollow road one spring morning and encountering a large snapping turtle plodding up toward him. This happened twice in the almost 30 years he commuted to State College. One turtle was only a quarter of a mile from the river, but the other had made it over a mile. In both cases, Bruce stopped the car and waited patiently for it to get out of the way.

Each time I was green with envy and rushed down to look for the creature. I was hopeful that the turtle was a female and looking for a place to lay her eggs. After all, the American or common snapping turtle Chelydra serpentina serpentina has been known to live in small streams like ours and to bury a clutchful of 11 to 83 white eggs in the mud of streambanks. But both times we never saw another sign of a snapping turtle. Whatever they had been doing on our road, they obviously had turned around at some point and headed back to more suitable habitat in the river.

Water birds have also made unexpected visits here. Last April Bruce saw a belted kingfisher sitting on a tree branch at the edge of First Field, at least a mile and a half from the river. Since April is a migration month for kingfishers, it may have been resting before moving down to the river where belted kingfishers have nested for years in the riverbank. As we cross the one lane, steel bridge over the river, we often see them flying back and forth and hear their loud, rattling calls. Sometimes one even perches on the wooden bridge railing.

A more frequent avian visitor has been the great blue heron. Still, I was startled to flush one from the edge of the Far Field one morning. According to Robert W. Butler, who has written the definitive account of this species for THE BIRDS OF NORTH AMERICA, although great blue herons are primarily fish eaters, they will stalk over upland fields in search of voles and other rodents. Yearlings, which often have a hard time catching fish, are most likely to hunt for small mammals in fields. So, perhaps, that great blue heron I saw, and the others that occasionally fly over our First Field, are not out of place at all, but merely searching for food.

Probably the most amazing avian river visitor appeared here on October 4, 1989. It was one of autumn’s glorious days–breezy, cloudless, and crisply cool. As I descended First Field through the locust grove, I heard a high-pitched cree-cree-cree. It could only have been an osprey. I stopped and scanned the sky with my binocular. Finally, I spotted it circling above me, a fish clasped tightly in its talons.

It made several passes over the field and then flew to a tree branch on Sapsucker Ridge where it stood and looked around silently. Moving slowly, I sat down in the locust grove and watched it through my binocular. The top of its white head glowed in the sunlight, while its broad, dark, eye and cheek stripe flowed down the back of its neck like a cowl. It sat motionless, ignoring the fish in its talons, and only looked alertly around when a nearby pileated woodpecker called.

After half an hour, I slowly stood up and started moving toward the osprey, hoping for a closer view. This aroused it from its reverie, and it started calling again as if warning me off. Then it leaned forward, displaying snowy white underparts, before taking flight, still grasping the brown fish it had probably caught in the river. No doubt it had been migrating since the migration period for ospreys in Pennsylvania extends from the second or third week in August to the fourth week in October.

Our mammal visitors from the river have been even more surprising because our Plummer’s Hollow stream, which originates from springs in First Field, is never much more than five feet wide as it flows the mile and a half down to the river. Because, in summer and fall, it is often barely a trickle, it does not support fish although it does have a good population of crayfish and provides a damp environment for salamanders.

So what was a mink doing halfway up the hollow, poking its nose in woody debris spanning the stream one April day in 1997? Mink, after all, prefer to eat muskrats, although they will settle for small mammals such as voles, mice, shrews, cottontails, and even squirrels, all of which live in our hollow. And crayfish are a favorite summer food, followed by muskrats, frogs, fish, snakes, small mammals, and waterfowl.

Again, I was not lucky enough to see the mink, but Tim, one of our hunters, was taking a noonday walk, and had an excellent view of the creature. Perhaps it was a female in search of a den site since mink will sometimes construct dens along the banks of streams or under stumps and logs, and they commonly give birth in April or May. But they usually take over abandoned muskrat houses, and, so far, we have not seen muskrats up here.

Early last May another hunter friend, Jeff, drove up to show us the body of a nursing mink he had found by the side of the highway next to the river. As we admired her almost untouched, silky, chocolate brown coat, we could see why mink fur is so popular. Her death by car meant that her litter of from four to nine probably perished, although both parents do rear the young and bring food to the den. But weaning the kits does not begin until they are five to six weeks old. Since wild mink usually live three to six years, we wondered if the dead female was the same mink Tim had seen three springs ago? As usual, nature presented us with more questions than answers.

Then, last February 27, we had our strangest visitor yet from the river. It was 42 degrees and overcast at dawn. Misty rain had been falling off and on for days and most of the snow had melted. Every spring on the mountain spouted water into our stream. Lying in bed, I could hear water rushing down the drainage ditches. Another dull day, I thought, as I listened to one of three wintering song sparrows singing.

But, as I went into the kitchen, the intercom buzzer from our guesthouse went off. Our eldest son, Steve, who was visiting for the weekend, yelled, “Mom, come quick! There’s a beaver in the stream below the guesthouse.”

At first I didn’t believe him. But as he insisted, I grabbed my binocular, pulled on my boots and jacket, and ran down in time to see an adult beaver emerge from the culvert pipe beneath the road. I was amazed at how large it was especially when it stood up on its hind legs beside the drainage ditch to look around. We had plenty of time to study its paddle-shaped tail lying flat on the lawn and admire its sleek, dark brown coat.

Although our sons Dave and Steve stood with me on the guesthouse porch less than 50 feet from the beaver, quietly talking, it seemed supremely unconcerned by us. Perhaps it was looking over the terrain and trying to decide if it had potential as a future home. But two houses and three adult humans were probably enough to discourage it. After five minutes of indecision, it continued up the drainage ditch toward the powerline right-of-way, wading through the six inches of flowing water.

I rushed back to our house to rouse Bruce who grabbed his camera and tripod. Together we ran up our driveway to the powerline right-of-way ahead of the beaver. While I stood on one side, scanning downstream with my binocular, Bruce crossed the ditch and set up his camera and tripod on the embankment above.

When the beaver came into view, I called quietly to Bruce, “Here it comes.”

Remaining still and out of sight, I watched while the beaver attempted to climb over a fallen tree and then toppled over backward. Undeterred by that setback, it tried again and made it over what must have been the last of dozens of fallen trees that span the stream.

It waddled determinedly up the ditch, by then only intermittently filled with meltwater. Finally, it sensed Bruce above it and stopped. Again it sat up on its hind legs and peered toward Bruce, who shot picture after picture before the beaver slowly turned around and headed downstream.

Again we watched from the guesthouse porch as it went down into the culvert pipe and emerged in the stream directly below us. Hopeful that it might set up housekeeping in our marshy meadow, I didn’t follow it down the mountain. But our marsh is only an acre at most, and it doesn’t have enough of the preferred winter food trees–aspen, sugar maple, tulip poplar and willow–or the aquatic plants, forbs, and grasses that beavers eat in the summer. They also like flat terrain or valleys and large streams with enough water for damming. Like the mink, the beaver ultimately rejected our marginal beaver habitat, or so we surmised. Still, I searched the stream for several days before giving up hope.

Probably the beaver we saw was a two-and-half-year-old that had voluntarily left its parents’ lodge and was looking for a home of its own. But it was a couple months ahead of schedule according to the books I checked. Usually a mature beaver leaves its parents and younger siblings between April and September and becomes a floater segment of the population, following water courses as far as twelve and a half miles from its natal home in search of its own turf.

This beaver, like many of the wild creatures we encounter here, had not read the books and had instead set out on its own during February’s thaw, convinced by the sound of running water that spring was here to stay.