An online resource based on the award-winning nature guide

December

Hooded Mergansers Seek Open Water

hooded merg in snow 050Hooded Mergansers are short-distance migrants that can be found in eastern North America year round where ponds and rivers remain open and slow-moving fish, insects and crayfish are plentiful. Some individuals migrate south and southwest in winter — 80% of birds banded in Maine, Vermont, New Hampshire and New York were recovered in coastal Atlantic states from New Jersey to Florida. A smaller number actually migrate north to spend winters in the Great Lakes and southern Canada. While numbers swell in March/April and November in northern New England due to migration, if there is open water you may well see Hooded Mergansers this far north throughout the winter.

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Huddling to Keep Warm

flying squirrel3 IMG_8550Animals which remain active year round in northern New England use different strategies to survive the cold winter temperatures. Lowering metabolism through torpidity (on cold nights black-capped chickadees and other species reduce their body temperature as much as 22 degrees Fahrenheit from their daytime level in a process called regulated hypothermia), shivering, caching food in the fall, puffing out feathers to create insulating pockets of air, excavating tunnels under the snow, seeking protection in cavities – these are just a few of the life-saving techniques used by mammals and birds which neither migrate nor hibernate.

Another strategy which some of these animals use is to huddle together to conserve warmth. Huddling reduces the animal’s surface-area-to-volume ratio, since it turns many small animals into a single big animal. The larger the animal, the smaller the surface-area to volume ratio and the less relative area there is to lose heat.

Bluebirds and flying squirrels are two animals which huddle to keep warm. Eastern bluebirds may huddle together in a tree cavity or hollow log in groups of up to ten. Flying squirrels often huddle together in large communal nests, sometimes with populations numbering over two dozen squirrels, in an effort to keep warm. If this is not sufficient, the squirrels will enter a state of torpor until temperatures return to normal. (Thanks to Susan Parmenter for photo op.)

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Coyotes Feeding on Deer Carcasses

12-22-14 deer carcass 394Ninety percent of a coyote’s diet is animal matter, including creatures as varied as meadow voles, mice, muskrats, raccoons, beetles and grasshoppers — basically, anything it can outrun. Coyotes have the reputation as major predators of deer. While research confirms that deer (and rabbits) comprise a good portion of a coyote’s diet in the Northeast, the majority of the deer that coyotes consume is scavenged as carrion (see photo). Because they cannot move as fast as adult deer, fawns are more vulnerable to coyote predation.

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How Beavers Digest Cellulose

12-26-14 beaver sign 125Some beavers are still managing to find openings in their ponds which give them access to fresh cambium, the soft layer of wood just under the bark of a tree. Cambium contains a lot of cellulose, in addition to starches and sugars. Like all herbivores, beavers do not possess enzymes that are capable of breaking down the large cellulose molecules (cellulases). In their place, beavers employ micro-organisms, such as bacteria, that can break down cellulose.

These bacteria are located in a pouch called a cecum, located at the beginning of the large intestine. (Ruminants such as moose and deer have rumens in place of ceca.) Colonies of these microorganisms in a beaver’s intestines digest up to 30% of the cellulose from the woody material that it eats. Further nutrients are recovered in the form of fecal pellets that the beaver re-ingests.

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Overwintering Red-tailed Hawks

12-24-14 red-tailed hawk-juvenile 002Red-tailed hawks are “partial migrants” — some individuals are migratory, and others are not. Many Red-tails living in the northern portion of the species’ range in southern Canada and northern United States migrate to more southerly locations for the winter. A few northern birds, however, remain on their breeding territories even in the most severe winters.

Overwintering Red-tailed Hawks are generally easy to spot, as they often perch on dead trees overlooking open fields and on telephone poles next to highways, where they watch for prey. Mice, voles, squirrels, snowshoe hares and an occasional bird make up most of their diet. If you notice the coloration of a Red-tailed Hawk’s tail, it will tell you whether the bird is a juvenile or adult. Adults have rufous tails; juveniles have barred, brownish tails. Seconds after this photograph was taken this juvenile Red-tailed Hawk killed and consumed an American Crow while being mobbed by more than 50 other crows.

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Northern Red Oak Buds

12-23-14  red oak terminal buds IMG_6865There are approximately 600 species of oaks in the genus Quercus, all of which are in the Beech family. This genus has two subgroups, the red oaks and the white oaks. The leaves of trees in the red oak group have sharply pointed lobes with bristles. The white oak group has leaves with rounded lobes lacking bristles. Although usually there are some leaves on an oak tree that persist well into the winter, it is helpful to be able to identify a species by its buds alone. Oaks tend to have multiple terminal buds. Northern Red Oak’s terminal buds are large, pointed, cone-shaped and covered with reddish-brown, mostly hairless scales that overlap like shingles, with one edge covered and the other edge exposed.

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Muskrats Enjoying Last Days Above Ice

12-22-14  MUSKRAT IMG_3496Muskrats and beavers are eking out the last few days that they will spend above the ice for perhaps several months. Fortunately for muskrats, they can hold their breath and remain under water for up to 20 minutes, time enough to get from one unfrozen patch of water to another. Once the ice freezes completely, muskrats will use ‘push-ups’ or ‘breathers’ as resting places and breathing holes — masses of vegetation collected from underwater and pushed up through cracks or holes in the ice.

Throughout the year muskrats eat the roots and stems of a number of aquatic plants as well as crayfish, frogs, turtles and other prey, when available. Unlike beavers, muskrats don’t store food for the winter, but forage for vegetation (see green plants on ice). Sometimes muskrats will feed from the winter food supply piles gathered by beavers. They have also been known to use the walls of their own lodge as food.

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