Within One Watershed:

Essays from Hackleman Creek

Part 2

The Valley

Wetland Secrets 

The creek murmurs softly a hundred yards in the distance. Shafts of gentle morning light angle down through the tree canopy to bathe the forest floor in a cathedral glow. With no particular destination in mind, I walk the woods without benefit or need of a trail. Wandering westward through the middle portion of the Hackleman Valley, I am greeted by a loud chorus of rib-it, rib-it, rib-it: the familiar song of Pacific tree frogs.

The two-inch males are advertising their desirability to the slightly larger females, who remain quiet. To make his amorous call, each male frog shuts his nostrils and inflates his throat sacs, amplifying the sound of air rushing over his vocal cords. When a female hears a call to her liking, she follows the sound until she finds her chosen mate waiting in shallow water.

I’m drawn to the sounds, too, and soon find myself approaching an opening beyond the trees where they seem to resonate most loudly - but when I step out from the woods at the fringes of a wide wetland, the frog chorus stops immediately; apparently the males have sensed my intrusion.

A heavy sweet musk hangs in the air: the scent of skunk cabbage. The flowers, each a club-shaped stalk cloaked by a bright yellow hood, dot the saturated ground. Huge waxy leaves, each two feet long and a foot wide, look like something a stegosaurus would have relished millions of years ago. The scent these plants release mimics the smell of rotting meat to attract pollinating flies and beetles. Carefully picking my way from one dry spot to the next along the spongy ground, I nearly step in an enormous pile of coal-black bear scat filled with green chunks: partially digested skunk cabbage.

Beetles and flies aren’t the only ones attracted to the fetid aroma of this plant; black bears seek it out for its laxative properties after they awaken from hibernation. The last thing a bear ingests before denning up for winter is a combination of hair, dirt and conifer needles; this clump forms a fecal plug in the bear’s intestine. The bear will not defecate or urinate during hibernation, but when it wakes up in spring, it needs to unplug itself before it can begin feeding on fresh spring grasses and forbs. A large helping of skunk cabbage does the trick.

My next step sends a tiny Pacific tree frog leaping out of the way. After a minute of artful frog hunting, I have it in my hand. Its dark throat tells me he’s a male. He sports the black eye stripe typical of his species and his skin color is a gorgeous mix of bright spring green and coppery brown. This pattern may only be temporary, as these frogs have the ability to change their body colors in response to environmental conditions. Tomorrow he could be completely brown or green or an entirely new palette of earthy tones. I gently put him back and push deeper into the marsh.

 Parting a snarl of willow branches with my hands, I get a view across an open expanse of still water; then I notice it: a ridge of sticks and mud about three feet high stretches at least 100 yards along the edge of the flooded clearing, impounding the water. This pond is the work of beavers! Grasses, forbs and willows growing on the dam indicate that it’s been here for many years, harboring multiple generations of the aquatic mammals.

I slosh back to dry ground and walk along the bank to reach one end of the dam. Cut branches mantled with a criss-crossing of smaller sticks protrude from the mud. Gnawed tips point skyward; rocks and gobs of gooey vegetation plug the weak spots, making the dam nearly watertight.  In damming this tributary of Hackleman Creek, the beavers have engineered a deep-water haven for themselves and created a biologically rich wetland habitat that benefits multiple species.

As water pools in the pond, it gradually soaks into the soil, where it cools down and flows underground below the dam into Hackleman Creek, chilling the water downstream. The dam traps and holds sediments, creating clear water and clean gravel beds necessary for aquatic insect larvae and spawning fish downstream. Water impounded behind the dam inundates and kills trees, creating nesting sites for ducks, woodpeckers and other cavity-dwelling birds. Willows felled by hungry beavers re-sprout even bushier the following spring, providing excellent cover for songbirds. The pond’s rich insect life feeds fish, which in turn sustain Belted Kingfishers, Great Blue Herons, Bald Eagles and other piscivores. Occasional breaks in the dam offer fattened fish a chance to escape and join their kin in the main stem of the creek. Pond plants absorb phosphorus and nitrogen carried in runoff, slowly releasing the vital nutrients into the watershed over time.

Pondering the gifts that beavers bestow upon a watershed, I amble close to the water’s edge. Several sticks, stripped bare of their bark to expose the sweet cambium layer that makes up the bulk of the beaver diet, rest below the glassy surface: the remains of a recent meal. Looking closer, I see an underwater opening leading into the bank below me. Further investigation reveals countless sticks, gnawed on both ends, plastered with mud over a gap between exposed tree roots under my feet. Lost in thought, I’ve unknowingly wandered onto the roof of the beavers’ house. Instead of building the classic mounded beaver lodge in the middle of the pond, these animals have burrowed into the bank beneath the interlacing root system of an old tree to create a predator-proof home. Within its dark interior, adults tend to their infants with help from the kits born last year. The two-year-old kits left the family to strike out on their own when this spring’s newborns arrived. I quickly step away from the beavers’ home, hoping I haven’t disturbed any of the residents.

Afternoon shadows grow long, signaling the time to head back. I leave the pond and its skunk-cabbage perfume. My departure prompts the all-male frog choir to resume its performance. As I retreat deeper into the forest, the ardent sounds soon fade, replaced by the creek’s soft singing. I head for the car, thankful for the revealing of more Hackleman secrets and another day to witness the workings of this watershed.