Because of the popularity of hazel nuts, it is surprising to find viable fruits on Beaked Hazel (Corylus cornuta) in mid- to late winter. Ruffed Grouse, Wild Turkey, Red-bellied Woodpeckers, Beavers, Snowshoe Hares, Raccoons, Red Squirrels, Eastern Chipmunks and White-footed Mice all vie for these delectable nuts.
This multi-stemmed, wind-pollinated shrub bears fruit that is wrapped in a modified leaf (involucre). Beaked Hazel (as opposed to American Hazel, Corylus americana) is named after the tapering beak-shape of its nuts’ involucres. One might suspect that any fruits remaining on hazel shrubs at this time of year must not be edible, but the photographed specimen was very tasty!
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Beavers spend a great deal of time tending to their coats, grooming several hours a day throughout the year. Grooming consists of removing sticks and debris that have become embedded in their fur, as well as applying oil from their anal glands to waterproof their fur. Waterproofing is essential, as it prevents the cold water from penetrating their fur. Typically they sit with their tail between their hind legs, stretched out in front of them, with their anal glands exposed. Beavers procure the oil with their front feet, and use all four feet to comb it through their fur. The two inside nails on both of their hind feet are split, increasing the efficiency with which they can apply the oil. Sometimes two beavers will groom each other, engaging in “mutual grooming.” The male and his offspring begin to groom each other when the kits are only two weeks old, yearlings and kits from three weeks on, and the mother and kits when the young are four weeks old. Mutual grooming continues as long as they are a family unit. ( I am humbled by the response to yesterday’s post. You will each be hearing from me soon. )
Ice is starting to form on ponds, and days are numbered when beavers can be out grooming themselves on land or eating freshly-cut branches. As long as the ice is thin enough to crack by swimming up under it and bumping their heads against it, they will do so, for soon it will be thick enough to lock them into their pond. Life under the ice is challenging. At 32 degrees F. a beaver’s resistance to heat loss in water is about 1/8th of that in air at the same temperature. This is due to the fact that its fur is compressed in the water, allowing the insulating air between the hairs to escape — a beaver’s pelt accounts for about 24% of its total insulation in water and body fat is responsible for the rest. Heat is also retained through a beaver’s tail and hind legs, which serve as heat exchangers. In the summer, a beaver can lose 25% of its body heat through its tail, but it only loses 2% in winter. Even so, it’s no wonder beavers risk getting a headache in order to see the sun for the last time until spring.
Beavers are meticulous housekeepers, in that they almost always defecate in the water, not in their lodge, and rarely on land. The best place to find their scat, should you be so inclined, is where they have been working for an extended period of time — for example, in the water adjacent to their dam. Their scat consists of 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 if disturbed. Their light color makes them visible even under water. Congratulations to all who guessed correctly — I’ll make the next mystery post even more challenging!
2-29-12 Beaver Sign of Spring
Anyone who buys and consumes the pale, relatively tasteless, store-bought tomatoes in the winter, and then, finally, can eat their own garden tomatoes right off the vine, will identify with the winter and spring diets of beavers. While they are locked under the ice, the beavers’ entire winter supply of food is a pile of branches they store at the bottom of the pond near their lodge. Once the ice on the pond begins to melt, beavers take immediate advantage of any escape holes, enlarging them if need be, in order to make their way to fresh, nutritious food. While their preferred spring food, herbaceous plants, are not yet up, the fresh cambium of living trees is most likely a welcome change from their water-logged winter food. It is always fun to come upon signs of their activity when there’s still snow on the ground – it’s one of my favorite signs of spring.
Beavers, like many mammals, communicate with chemical signals. In scent marking, beavers actually build a mound of mud on which to place their scent. First they dive down to the bottom of their pond, dig up an armful of mud with their front feet and swim to shore with the mud held against their chest. Walking on to the shore on its two front legs, the beaver deposits this mud next to the water. Beaver scent mounds can be quite small, or as high as three feet or more, depending on how many loads of mud they contain. The beaver straddles this pile of mud and applies castoreum from its castor glands, or anal gland secretions, or both. The purpose of building a mound is to elevate the odor (helps with scent dispersal), to intensify the odor by putting it on a moist substrate, and to protect it from flooding when the pond level fluctuates. Beavers build most of their scent mounds in the spring, when young beavers are dispersing and claiming new ponds, but I have found several fresh ones this fall, including the one in the photograph. (Click on photo to enlarge.)
There’s a period of time in the fall, and again in the spring, when pond ice is thin enough to break under the pressure of a beaver’s head punching it from underneath, but is not quite hard enough to support the beaver’s weight. After an audible crack, a beaver’s head emerges from the recently-made hole in the ice, and immediately the beaver lifts its front feet up onto the edge of the ice in front of it and then lunges forward, breaking a path with its body through the ice to where the beaver wishes to go. Over and over the beaver lunges, pausing periodically to catch its breath. Why the beaver doesn’t swim under water from point A to point B (beavers can swim up to half a mile underwater, and remain submerged for up to 15 minutes), which would mean having to break through the ice only once, when it gets to where it’s headed, instead of laboriously breaking trail through the ice is unknown to me, but the process is great fun to observe.
If there’s any species that knows how to survive a heat wave, it’s beavers! More at home in water than on land, the beaver can hold its breath for up to 15 minutes, and swim up to half a mile under water. Beavers also have valves in their nose and ears that automatically close when beavers are submerged, and transparent nictitating membranes that act as a third eyelid, covering and protecting their eyes under water.