The lazy, hazy days of summer are dwindling, and beavers’ internal clocks are telling them it’s time to batten down the hatches and prepare for several months of life below the ice. This entails adding a significant amount of mud to the outside of their lodge. The mud freezes and creates an impenetrable barrier between them and predators such as coyotes that, thanks to ponds being frozen, will have access to beaver lodges. This mud is anchored by the addition of debarked branches and logs that have provided the beavers with meals of cambium during the summer.
A beaver can transport its own weight in material (roughly 45-60 pounds). Retrieving debarked pieces of wood in many cases involves carrying them over both land and water, using only jaws and sometimes a shoulder for support. A beaver’s short, muscular neck and its powerful lower jaw muscles make this possible. Try lifting one of the larger logs on a lodge or beaver dam sometime. Then imagine carrying it any distance in your mouth with no assistance from your hands. (This feat rivals that of a moose carrying two 25 – 30 pound antlers around for several months.) While there are recorded cases of beavers felling trees 150 feet tall and 5 feet in diameter, logs of this size are not used as building material for dams and lodges, but rather the bark and upper branches provide them with food. (Thanks to Roger and Eleanor Shepard and Sara and Warren Demont for photo op.)
Little did I know when I wrote yesterday’s post about the silver lining of our low water levels that I would so quickly encounter another predator benefiting from the current drought. I have spent a considerable amount of time this summer watching three generations of beavers do their best to survive as their pond proceeded to diminish to the point of exposing one of their lodge entrances and confining them to an increasingly small body of water. The underwater entrances to a beaver lodge are vital to their protection, and predators are well aware of this.
Yesterday the importance of water as a protective barrier was made very clear to me when a coyote appeared on the opposite shore of the beaver pond from where I sat. It stood for several seconds exactly where the beavers leave the pond on their way to nearby woods to cut poplars and birches which they haul back to their pond to eat. A well-worn trail marks the spot. You could imagine the coyote, upon surveying the shallowness of the pond, telling itself to be patient, as better days were just around the corner.
Moments after the coyote left, the mother beaver got out of the pond precisely where the coyote had been standing and took a few steps before sniffing the ground and then the air (see insert). Being nocturnal, beavers have an acute sense of smell which they use for detecting danger, food and for communication with each other. It took mere seconds for the beaver to detect the scent of the coyote, at which point she turned and sought refuge in the dwindling amount of water remaining around her lodge. May the heavens open up soon.
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With their breeding season nearly at an end, red fox vixens are preparing for the arrival of a litter of pups in March or April. This involves locating and cleaning several dens, and then choosing one in which to give birth and raise young. An adult female red fox may use the same den year after year; eventually one of her daughters may take it over.
While specific den locations vary, most are on sandy hillsides, often in the woods but close to an open area, and usually there is water within 300 feet or so. A den typically has several entrances, with the main one measuring about ten inches in diameter. At this time of year (if there is snow on the ground) it is relatively easy to locate fox dens, due to soil that has been removed and scattered on the snow.
Vixens often renovate an abandoned woodchuck burrow, but occasionally den underneath an outbuilding, in a hollow log, rock pile or other sheltered area. Pictured are a typical hillside den as well as an abandoned beaver lodge that has been renovated by a fox. Scat (located about 2 o’clock in the photo) deposited near the entrance of the lodge indicates that this may well be a den that will be used for raising young.
Reproductive activity begins when a beaver reaches the age of three years. Beavers mate in January and February, with the peak activity in mid-February. Typically mating takes place in the water (under the ice), but can occur inside their lodge. Kits, usually three or four, will be born in May or June. Beavers are monogamous and pair for life. (Note: ponds still frozen – photo not recent)
Beavers are meticulous housekeepers, in that they almost always defecate in the water, not in their lodge, and rarely on land. Because of this, it is rare to see their scat, but fall is as good a time as any to look for it (should you wish to see it).
In preparation for winter, beavers are repairing their dams and lodges, and stock-piling a winter food supply pile of branches in the pond near their lodge. They spend a lot of time working in the water in one area, which means that signs of their presence, including scat, are plentiful in these areas. If you look in the water along a beaver dam at this time of year, it’s highly likely that you will find light-colored, kumquat-size pellets, which, as you might expect, are full of tiny bits of woody fiber. The pellets are essentially little balls of sawdust, and disintegrate easily. (Handling, for those tempted to do so, is discouraged due to giardia or “beaver fever.”)
Beavers are hard at work refurbishing their mud and stick lodges in preparation for the coming winter, when their movements will be restricted and they will spend both days and nights inside their lodge. When we think of a beaver lodge, we picture it in the middle of a beaver pond. This was not always the case, however, and still isn’t today. The earliest and most primitive beaver lodges consisted of a burrow in the side of a high bank with the entrance under water (see exposed bank lodge entrance in photo insert). The next advance was the addition of sticks and mud piled over the top of the bank as added protection from predators (see photo). Eventually beavers started building a complete lodge on top of the bank which had an underwater entrance. The most advanced design is the lodge we most commonly associate with beavers — one that is built up from the bottom of the pond and is completely surrounded by water. It requires the greatest amount of work but offers the greatest amount of protection to the beaver.