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Posts Tagged ‘beaver lodge’

After running some errands in Brockville on Friday, RailGuy and I visited the Mac Johnson Wildlife Area, located on the northern edge of the city, and enjoyed a short hike. The day was a bit overcast, but it was mild and there wasn’t much wind. The main feature of the wildlife area is a large lake and wetland, and several trails follow the shore of the lake and wind through mixed woodland.

We followed the Railway Trail, which is so named because about half its length follows the abandoned bed of a railway track. It was quiet in the woods, as is usual at this time of year. Apart from a troop of chickadees, we didn’t see any wildlife stirring. However, there were signs of summer activity.

Close to the trail, I noticed this nest, still in good shape for so late in the winter. The weather has taken a toll on many nests by February. From the trail, it looked like a woven ball, but by pulling the branch down a bit, the interior of a nest was revealed. It was probably constructed by a red-eyed vireo (Vireo olivaceus). Red-eyes are common woodland birds, but they are more often heard than seen as they usually sing from perches high up in the canopy of the forest. They are about 6 inches long, a bit bigger than chickadees, and rather plainly dressed in olive grey. They really do have red eyes. Their song always reminds me of a hyper robin.

The nest, constructed by the female, is typically deep-cupped and suspended in a horizontal fork of a slender tree branch. She uses grasses, paper, bark strips and rootlets. It may be bound to the supporting twigs and covered on the outside by spider webbing.

Another tree showed evidence of yellow-bellied sapsuckers (Sphyrapicus varius). Sapsuckers drill holes in trees in spring and drink the sap, usually early in the year when insects are still scarce. Their handiwork, or maybe billiwork is very distinctive. The small holes are drilled in orderly rows. These holes may have been a couple of seasons old. They were perhaps drilled in 2008.

This snag had been well-worked over by a piliated woodpecker (Dryocopus pileatus). Piliateds are very large woodpeckers, about 18 inches in length. They are year-round residents, but it is more usual to find their excavations, sometimes very large, than to see the birds themselves.

The rail path leads down to the waterfront. Looking out over the lake, we spotted a paraskier near the far shore. He/she was moving along quickly…until a tumble.

Close to shore, there were a few muskrat lodges.

Farther along the trail, this pile of branches suggested a beaver had been at work at some time, but the lodge didn’t look occupied. In fact, the long stems and seed pods of Swamp Milkweed (Asclepias incarnata) were springing from the branches.

On a section of the lake near the parking lot, ice had been cleared for an outdoor skating rink, and there was even a heated cabin for changing into skates available. Probably the ice is busy on weekends, but on a Friday afternoon, there were no skaters on hand. The park is a nice spot for dog-walking and is probably popular, being close to the city. We just met one dog and his walker, as we were returning to our car. Samson was delighted to meet RailGuy. Mac Johnson Wildlife Area offers Brockville residents a great spot to enjoy nature close to the city.

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ucbsentrance

As noted earlier in the week, the November full moon is also known as the Beaver Moon. Sure enough, when we visited Upper Canada Bird Sanctuary, there was evidence that beavers (Castor canadensis) had recently been hard at work, getting ready for winter.

ucbshousefrompath

Not far from the entrance to the trail, a beaver lodge was nearing completion. Beavers are well known for building dams. However, they only construct dams if it is necessary in order to maintain the water level at a depth sufficient to ensure that the bottom of the waterway won’t freeze. This is required in order to provide underwater storage for winter food and year-round underwater access to the lodge, secure from predators.

ucbsbeaverviewofwater

The lodge may be located in the middle of a pond, or on the bank of a waterway, as in this case. Lodges are usually built over about a month in the autumn. The lodge includes a feeding den, a resting den, a source of fresh air, and usually more than one underwater tunnel, which allows for a means of escape should a predator enter the lodge through one of the tunnels.

ucbsviewoflodge

The lodge is constructed from a pile of twigs, branches and bark. As freezing weather begins, the beavers use their front paws to plaster the lodge with mud, leaving an air intake near the top of the lodge. This makes a concrete-like outer shell that predators can’t break through. Inside, the dens are constructed on a platform about 10 centimetres above the water line. They are created by gnawing out space in the pile of branches. The average lodge is about 5 metres in diameter and about 2 metres high. The lodge may be occupied for many years. In winter, it may be home to a pair of adults, their yearling kits and the young of the year.

ucbstopoflodge

Most of the branches used in the construction of the lodge were small in diameter. On average, a beaver cuts down about 215 small trees (under 40 cm in diameter) a year. These beavers had to bring the branches from quite a distance, as the lodge was located well away from the edge of the forest. There were multiple trails through the cattails at the edge of the water.

ucbsbeavertrail

Perhaps it was this long trip to drag branches back that inspired the beavers to try taking down one of the larger trees closer to their lodge. It was an ambitious undertaking, still in progress! If you would like to read more about beavers, visit Bibliophilia Monday: Two About Beavers for a couple of suggested titles.

ucbsgnawedtree

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valleyview

On July 5th, Japan’s Emperor Akhito and Empress Michiko visited the Mer Bleue Conservation Area as part of their eleven day tour of Canada. The protected area encompasses 33 square kilometers southeast of Ottawa. It’s main feature is the Mer Bleue wetland, about 50% of which comprises a sphagnum bog, rare this far south. It was designated as a Wetland of International Significance under the Ramsar Convention in October of 1995.

openwater

The name, Mer Bleue, is French for Blue Sea. It is thought that the name reflects the appearance of the bog when it is shrouded in an early morning mist. RailGuy and I took a walk on the boardwalk trail on the weekend. The trail is 1.2 kilometers long and begins on a sand ridge that overlooks the bog. The boardwalk leads first through an area of marsh and open water, home to beavers, muskrats and other wildlife, and then enters the bog.

bogpasture

Near the point at which the boardwalk enters the bog from the marsh is an interpretive sign that outlines the acidity level of the bog.

merbleueaciditychart

Water in the bog has an acidity level, or pH, of 3 to 4, making it up to 1000 times more acidic than milk. The sign shows the standard acid/ base scale that runs from 0 (very acidic) to 14 (very alkaline). Each increment on the scale represents a 10-fold increase. That is, 3 is 10 times more acidic than 4.

spraphum

The high level of acidity is the result of poor drainage. No running water rinses the acidity from the bog and a specialized plant community that can cope with the high level of acidity develops. This includes larch and black spruce trees, Labrador tea and leatherleaf shrubs, and cottongrass and sphagnum moss.

tunnelweb

The webs of spiders, glistening in the sun, could be seen ornamenting the sphagnum and low vegetation, including this funnel web.

merbleutreedistance

While walking along the boardwalk, one tree caught our eye. It had a large, round globe-shaped growth situated conspicuously near its tip. A witch’s broom! I only recognized it as such because such a growth was recently featured on Birdgirl’s blog, The Marvelous in Nature.

merbleuepuzzlecloseup

Two beaver lodges were located near the boardwalk. One showed little sign of activity. The second, however, had gnawed branches floating nearby, suggesting it was in use.

beaverlodge

Passages through the marsh connected the lodge with open water.

passage

It was a very hot day, and the boardwalk leads through an open expanse where you are exposed to the bright sun. The trail returns through the marsh and then enters a final section of forest. Part of the forest was natural, while the remainder was an old pine plantation. The shade of the trees was a welcome respite from the heat of the sun.

For a visit to another bog, see this post on Alfred Bog.

trees

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