A few weeks ago I was both delighted and dismayed to discover the handiwork of beaver in a nearby wooded wetland, where the furry little engineers had constructed a barrier of aspen and birch branches and mud across a small culvert, damming the small stream running through it and creating a lovely wetland in its place.
It was beautiful and serene, as titmice and cedar waxwings flitted and twittered all around, and the autumn reflections of overhanging red maple, yellow birch, black cherry and hemlock danced in gentle ripples upon the surface of the newly formed pond. On the one hand, I celebrated the creation of this lovely new wetland as a gift of nature - wetlands provide critical habitat for fish, ducks, geese, turtles, amphibians, mink, deer and countless other creatures, while regulating and recharging ground water supplies, reducing erosion, filtering out sediments, detoxifying pollutants and minimizing flooding downstream. And I celebrated the creativity, ingenuity and adaptability of the beavers themselves, whose architectural, engineering and construction skills are nothing short of phenomenal.
But on the other hand, I also grieved, knowing that these particular beaver (probably a young, newly mated pair) were likely doomed - for their wetland was in the midst of property where their activity would not be tolerated by the landowners, and where human concerns over the loss of trees and flooding elsewhere would take precedence over the ways of nature. No other mammal has a greater ability to alter its environment than the beaver, except for humans. And rarely will humans tolerate the competition.
Holding a twig in its claws, a beaver gnaws the bark with its sharp teeth. Beavers are one of the largest rodents on Earth.
Photo by National Geographic
The North American beaver (Castor canadensis) is the largest member of the order Rodentia, named from the Latin "rodere," which means "to gnaw." Their scientific name refers to the beaver's castor glands, which produce a special scent with which they demarcate their territory. And masters at gnawing they are. With chisel-like incisors and powerful jaws, beaver can easily cut down a 5-inch thick willow in less than three minutes, merely by biting out chips in a deep groove around the trunk. Beaver especially seek out trees such as aspen, poplar, willow, birch and maple, some as large as three feet across, and use them as both food and as construction materials with which they create their dome-like home (the lodge) and their wetland habitat (via their dam). Once a tree is felled, beaver will typically trim off the branches, cut them into pieces and carry them in their teeth to the lodge or dam site, where creative construction varies according to the condition of the waterway. Larger branches up to 6-feet long usually provide the dam's scaffolding, which is then woven together and packed with smaller twigs, grasses, cattails and other plant material (even corn stalks) and then caulked with mud. Dams may be 6-feet high or more and can reach 25 to 40 feet across. The purpose of the dam, as impressive as its size may be, is to create a still, safe and relatively deep watery habitat in which the lodge may be built, winter food may be stored and young may be raised.
Next week I'll discuss the home and family life of these remarkable rodents, as well as how they manage to succeed in their frigid, semi-aquatic environment now that winter is approaching.
Becky Nystrom is a professor of biology at Jamestown Community College, a long-time CWC supporter and volunteer and a founding trustee of the CWC. The Chautauqua Watershed Conservancy is a local nonprofit organization that is dedicated to preserving and enhancing the water quality, scenic beauty, and ecological health of the lakes, streams, wetlands and watersheds of the Chautauqua region. For more information, visit www.chautauquawatershed.org or call 664-2166.