Anyone who frequents the Bloomingdale Bog Trail knows there are some very active beavers along the trail. The marsh at the southern end of the trail is dotted with a couple lodges, the inhabitants of which are responsible for the dams at the end of the marsh as the water runs north.

Go not even a mile up the trail to where it opens into the bog and you will see some even more impressive work, where the beavers have built a series of dams in the ditch along the trail. The largest dam is perhaps a mile and a half up from the south end, not far past the old rail car on the western side of the trail.

There the beavers – which have lodges mounded along the banks of the canal – have not only built impressively high dams, but have gouged out a deep channel across the entire trail which is filled with about three feet of water. They have also created a tunneling network of trails through the thickets when they cruise their timber.

beaver dam - Bloomingdale Bog
One of the many beaver dams along the Bloomingdale Bog Trail.

I often see beavers along the bog trail when I'm there, and this fall I've seen one or two pretty much every time I've been on the bog trail. After all, I'm often walking the dog in the evening when beavers are most active. In addition, beavers are also more active in the fall when they are compelled to cut an entire winter's supply of food and store it under the water, providing access to their food when ice is on the surface. It is in these cold months that beavers eat predominantly the inner bark of branches. During the summer much of their diet is composed of the green vegetation of aquatic plants which are flourishing at that time of year.

Beavers are well known for their tail slap in annoyance of any intrusion and they frequently show their displeasure with me and Wren in this way. It can be quite startling if you haven't already noticed a nearby beaver quietly gliding through the water. It is comical to watch Wren's reaction to them – she will excitedly smell the air when a beaver is nearby, get spooked by the tail slap, and then quickly regain her curiosity and go back to following her nose. Just the other night we were out on the Bog Trail and heard a beaver gnawing in the darkness. And then, slap! – it had sensed us standing there silently. We turned and left it alone to its work.

beaver Larry
A beaver on the ice. Beavers are the largest rodents in North America. Photo courtesy of www.masterimages.org.

The tendency of beavers to flood the bog trail has a few local dogwalkers regularly pulling apart some of their handiwork to drop the water level and keep water off the path – something that benefits all of us bog walkers. The beavers repair these holes quickly and the cycle begins again. But dam building isn't simply an inconvenience for hiking. It can fundamentally alter the ecosystem – creating habitat for the beavers (for instance they can store their stick stash in the water), and also creating habitat for other species as well. Hence we call beavers ecosystem engineers because how much they change their habitat. And we call them keystone species because their presence and activities have such a profound impact on other species.

After all, flooded forests can kill trees – making them prime for woodpecker excavation, and many species of birds, such as northern waterthrush and common grackles are often nest along beaver ponds. They are an important component to many ecosystems, and a consistent architect here in the Adirondacks. And although they are quite common, they are always fun to see. Do it now while the water is still open and they are actively stashing their winter supply.