Beaver dam (above) and eagle nest (below). Read more about eagles and beavers (pdf format).
Architecturally speaking, Ohios landscape has a lot to boast about. Yet the engineers for many of the states most impressive structures never spent a day in the classroom. From skyscraping nests to elaborate shelters and tunnels, the ingenuity of natures animal architects rivals that of the greatest engineering minds.
Long before the first degree in hydrodynamics was ever conferred, beavers were busy damming streams and engineering well-built riverside lodges. Industrious and dauntless, beavers are guided by instinct to dam up waters where a pond or lake does not already exist.
Like human engineers, beavers assess a variety of factors before building a dam, including whether the stream water is fast or slow moving. If its fast, they might build a second, smaller dam to help ease the waters pressure. In fact, beavers are so good at what they do that humans apply the same guiding principles to man-made dams.
Building from the bottom up, beavers wedge large sticks and logs in streambeds then add layers of branches that are held in place with rocks, mud and loose vegetation. Once a pool has formed, the focus shifts to building a lodge.
Also made of logs and sticks, the cone-shaped lodge receives coats of mud, sealing out bad weather and protecting the beavers from predators. Except for a small opening at the very top for ventilation, the sturdy structure becomes air and water tight. Cozy by beaver standards, the average lodge is 15 feet in diameter and protrudes about 5 feet above the waterline. As many as a dozen beavers may live in the lodge at one time.
Beaver dams can be seen in many places across Ohio, including Tinkers Creek State Nature Preserve in Portage and Summit counties. An area of rich peat, swamp and marshland, Tinkers Creek is the perfect habitat for busy beavers. Brian Stenger, a conservation worker at the preserve, suggests following the half-mile Seven Ponds Trail, where youll find good views of the resident beavers and their handiwork. Stenger noted that beavers are actively preparing for winter now, cutting and gathering twigs, bark, roots and other vegetation to sustain them during the cold days ahead.
Birds are also great architects. From the belted kingfisher that digs a simple cavity into a stream bank to the barn swallows nursery of mud pellets, nests are as varied as the birds that build them.
One of the most imposing nests is that of our national symbol, the American bald eagle. Soaring high above the Ohios patchwork of waterways, farmlands and forests, eagles were building their lofty dwellings well before steel and concrete skyscrapers ever rose from the ground.
An eagle pair, which typically stays together for life, shares in the responsibility of building a nest and rearing offspring. And choosing the right place to call home is a weighty matter, since the average eagles nest is 4 to 5 feet across and 3 to 6 feet deep! Taking that into consideration, its understandable why eagles favor large trees that can also support a nest some 50 feet or more from the ground.
Using their beaks and amazingly strong talons, eagles actually break off branches and twigs from nearby trees for nest material. Like beavers, they build in layers from the bottom up. Following a triangular pattern, a frame is constructed using sticks that vary in size from 12 inches to 8 feet in length, and up to 3 inches in diameter. Smaller material is woven between each layer for added strength and protection. Finally, with an eye toward comfort, the eagle pair finishes off a nest by lining it with grasses, cattails and even cornstalks.
The largest eagle nest of all time was recorded right here in Ohio. Appropriately called the Great Nest, it was built near Vermilion in the 1890s. The giant nest measured 8 _ feet across, was 12 feet deep and weighed nearly two tons the size of a small pickup truck! Perched 80 feet from the ground, it was used by different eagle pairs for more than 35 years until a storm blew it down in 1925.
Testaments to durability, eagles nests are often used by a succession of eagle pairs, year after year. Starting in late fall in preparation for the following springs nesting season eagles perform routine nest repairs by adding sticks, twigs and grasses. Now, with leaves off the trees in late fall and early winter, its a great time to venture out for a view of this off-season maintenance or perhaps to discover where a new nest is being constructed.
In 2003, Ohio recorded a modern record of 88 nesting bald eagle pairs that fledged 105 young. Several nest locations around the state (especially those in the Lake Erie region) offer an opportunity to glimpse eagles at their work. Inland, one of the most accessible sites is a nest at the Delaware State Wildlife Area in central Ohio.
Ohios amazing animal engineers are not limited to beavers, songbirds and eagles and you dont have to look far to find examples of their work. From mound-building ants to web-weaving spiders, the Buckeye State is full of these architectural wonders. The next time youre go exploring Ohios great outdoors, keep your eyes open for the well-built places that our wildlife calls home.