Wildlife Watching in America's National Parks: A Seasonal Guide

9. November—Beaver of Cuyahoga River Valley

142 | 9 { November Beaver of Cuyahoga River Valley Cuyahoga Valley National Park—located in northeastern Ohio just a half hour from the Cleveland metropolitan area and millions of people—is one of the newest parks in the National Park System. Surprisingly, even an “urban” park such as Cuyahoga Valley can conserve wildlife and provide quality wildlife-watching experiences. True, a visitor won’t find wolves or grizzly bears, but one will find many other fascinating critters, including species deeply connected with America’s heritage, like the American beaver. In some ways these new parks located near major metropolitan areas may be even more important than the remote wilderness parks in terms of conservation value, as they help to connect millions of citizens, including urban residents, with our natural resources. November is a great time to visit Cuyahoga Valley National Park and watch the beavers ' handiwork (or should we say “toothy work”) as they busily prepare for the coming winter. What’s Remarkable about Beavers? The beaver is one of the few creatures that, like humans, can modify their environment to better meet their needs. Once a beaver finds a suitable site in a stream or small river it begins constructing a dam (how they determine a site “suitable” is unknown, but they seem to do a good job at it). The dam is constructed from branches the beaver has cut from the nearby 143| November–Beaver of Cuyahoga River Valley uplands and mud it collects from the stream bottom or bank. The process and the logic that goes into building the dam is still somewhat of a mystery , but beavers typically start the dam by inserting some branches vertically into the streambed. This isn’t an easy task; a beaver must jam the pointed end of the branch far enough into the substrate so that the current won’t wash it away. The beaver then weaves horizontal branches between the vertical branches, all the time hoping that the vertical poles are fastened strongly enough to withstand the increasing water pressure on the dam. Mud and vegetation is then applied to strengthen the structure and to fill the holes. The entire construction may take months or even years. If the river or dam has a relatively steep grade the beaver may build a succession of dams, creating a stair-step series of ponds. As testament to their engineering prowess, dams on small low-flow streams are often straight across, whereas those on large high-flow streams are often bowed upstream to better withstand the immense force of the water (think Hoover Dam). Some dams also have spillways to Viewers don’t always need to see the animals to know they are around. Beavers leave as much or more sign than any other animal. (Photo by Gary W. Vequist) 144 | Fall relieve the water pressure during high-flow periods. The longest known dam, in a remote area of Canada, was over one-half mile long and was actually discovered by satellite imagery. Once the dam is completed a pond starts to form, providing the beaver the ideal environment it needs for food, safety, and to raise a family. Of course, like any engineered structure the dam requires regular maintenance. It appears that beavers are stimulated to repair a dam by both the sound of running water and changes in current. In one ingenious experiment, beavers exposed to a loudspeaker broadcasting the sound of running water began piling up branches. However, beavers also find and readily plug underwater pipes with water flowing through, even though the pipes produce no sound (as far as we know). Whatever the stimuli, when a dam needs repair the entire beaver colony gets to work immediately. Following the completion of the dam the next chore for the beaver is to construct a dome-shaped “lodge” out of more branches and mud. Within the cozy lodge the beaver will rest and raise a family. The structure is so solidly built that even bears cannot get to the occupants. The lodge’s underwater entrance provides a safe exit for the beaver as well as reliable underwater access during the ice-covered winter months. Yet the beaver’s work is never done. The next task is for the beaver to The old saying “busy as a beaver” is not without merit as the industrious animals are constantly repairing dams, building lodges, and stockpiling food, especially in the fall. (Photo...