Sunday, November 11, 2012

CASTOR CANADENSIS: I've called this critter by other names too, some unprintable....

(Written by Rose Moore 2006 after the Great July Flood)

HEADLINE: If a creek runs through it, the beavers will too

IF THERE'S ONE good thing about the recent flood damages to our Concord Township property, it might be that it has washed away a few squatters. Or so we like to think, but we're careful not to delude ourselves when it comes to these particular residents; we've been proven wrong before.

Over the years along our creek, this colony of CASTOR CANADENSIS (American Beavers) have been exercising their natural rights of eminent domain, acquiring ever-increasing amounts of our land. It was only a few years after we built our house on a high-point of our acreage that these buck-toothed, over-sized, bark-chewing, tree-eating, vegetarian rodents began sneaking in.

At first we were naive about the implications; when they began to build a dam, we sat quietly on our porch at dusk and happily watched them work. We felt lucky.

Then autumn arrived and the trees lost their leaves, and we were startled to see that at least an acre of formerly dry, wooded, wildflower-studded land on the other side of the water was now completely treeless; our furry neighbors had built a lodge there. As time went on, we discovered these interesting creatures can destroy acres of woodlands each year. They can and do erode creekbanks... And, as wildlife officials have told us, they can also destroy ponds, damage lake dams, block draining, flood roads...

One year we cheered as we watched the beavers' dam destroyed by our rain-swollen creek; perhaps they'd move out now, we thought. To our dismay, the beavers simply spanned the water with a larger dam upstream, just out of view. They also began enlarging their lodge, and the fetid mosquito swamp they had created continued to thrive and expand. It extended, in fact, into the rest of our woodland on that side of the creek, undermining roots, eroding banks, drowning trees and wildflowers...

Finally we applied for and received a nuisance permit and hired a trapper. Briefly it seemed the beavers were abdicating, but in their own court of nature and public opinion, the beavers always seemed to win their case and return in ever greater numbers. Eventually we gave up.

Conventional wisdom says the beaver sticks to quaking aspen (poplar), rarely chewing coniferous trees except for building purposes, or if the animal is in starvation mode. But if your property is populated by beaver colonies, you soon discover they also turn to hemlock, pine and spruce, red maple ("swamp maple"), wild cherry and other trees---even when good supplies of "favored foods" are easily available. (Some experts have speculated they do this for medicinal purposes).

The rodents also quickly clear saplings and brush from the understory where many wildlife species nest. They use branches of the fallen trees for food and construction, and they chew voraciously on the bark to keep their back teeth from outgrowing their front incisors. (Oh for orthodontia!)

CASTOR CANADENSIS WAS listed as extinct here in a 1940 Natural History of Lake County. (So was the Canada Goose). Beaver were re-introduced back into our streams more than 30 years ago; the problem is, they were brought back into a habitat that no longer had the predators (bobcat, lynx, giant river otter) to keep the beaver population in balance.

The population multiplied beyond expectatons. Before too long, the option of control by managed hunting clashed head-on with the anti-fur and anti-hunting movements, and soon the hunters and trappers found the fur market no longer could support their labors. The beaver population mushroomed.

For a time, the State of Ohio relocated destructive beavers at property owners' requests. But this largest of our rodents was prolific, and as the population continued to grow, Ohio discontinued the re-location program and ceased to even recommend it, because, I was told, "It only re-locates the trouble, which will soon return."

Our problems with Castor Canadensis are by no means unique to our property or even our county. Even the Park System had its problems with these critters in Washington, D.C. When the industrious mammals began to attack the famous cherry trees there, wildlife officials began to trap them, and they were set free elsewhere. (Hopefully not on someone else's land; the Park Service refused to say where).

I'm sure their troubles weren't over. A mated Castor Canadensis produces three or four pups each season, and several generations live and grow in one colony. As the lodges expand, the younger generations then begin to establish their own homes, building their own or moving into someone else's abandoned lodge. Any property owner who has tried to evict these aquatic mammals can attest to the fact that a vacated lodge is all-too-soon re-occupied by such squatter families. A wildlife officer once explained that to me with the declaration that "Nature abhors a vacuum."

About the time Castor Canadensis began moving into our own property, a Geauga resident warned, "My woodland trails went to bed intact for the winter, but by springtime we discovered the beavers had moved in, and what a mess!." He said he worried that his spring-fed lake would soon fall prey to these rodents "who like digging into earthen dams almost as much as they like building their own."

Around 1980, Concord Township trustees enlisted the aid of state wildlife people in removing a good number of these aquatic engineers who had become especially destructive to the properties around Brightwood Lakes. The animals were taken to a nature preserve in Hambden Township.

Soon officials and property owners throughout the region, especially in rural areas, found themselves "up a creek" without much help, when the animals' talent for obstructing drainage began flooding and eroding rural roads and damaging fields.

ON THE BRIGHT SIDE, things could be worse. Really.

There is sound evidence that Ohio was once frequented by giant predecessors of our rodent creekside tree-chewers. When the glaciers receded from northeast Ohio, allowing plant life to quickly take hold in the scree left behind, our bottomlands were prowled by huge Castor Canadensis who measured more than seven feet from nape of neck to base of hip. (They were tail-less). Eventually the blessing of Mother Nature's evolutionary widsom left us with a smaller version of the animal.

All I can say is, it's a good thing we didn't have anyone around at that time to insist on re-introducing the big ones!

(Rose may be out in high boots today, searching her creek for Castor Canadensis, which have returned a number of times since this was written)