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Archive for January, 2013

Woodland Snow Doughnuts

1-31-13 woodland snowdonuts by Ginny 1 27 (5) (2)Photo by Ginny Barlow

Snow Doughnuts

1-31-13 snowdoughnuts by Ginny Barlow  1 27 (1)A fairly rare natural phenomenon is the creation of snowballs without the help of any living creature. These structures, called snow doughnuts (there is a hole in the center of them) or snow rollers, require a precise balance of air temperature, ice, snow, moisture and wind in order to form. To begin with, the ground surface (typically quite flat) must have an icy, crusty snow, on which new falling snow cannot stick. On top of this, there needs to be about an inch of loose, wet, sticky snow. The air temperature needs to be around 32 degrees F. Last, but not least, there must be a strong, gusty wind blowing 25 miles per hour or more. Snow doughnuts begin to form when the wind scoops chunks out of the top inch or so of snow and these chunks roll, bounce and tumble just like tumbleweeds, downwind. They gather additional snow as they roll and become larger and larger until they are too large for the wind to push. Snow doughnuts can be as small as a tennis ball or as much as two feet in diameter, depending on how strong the wind is and how smooth the surface of the snow is. There can be hundreds of them in a field or patch of woods, usually on level ground. When a snow roller starts to form, there is no hole in the center of it. As it picks up speed and snow, the thin center crumbles, forming the snow “doughnuts.” (Thanks to Ginny Barlow for the snow doughnut photograph.)

Ruffed Grouse Roosts and Scat

1-30-13 grouse beds & scat IMG_2420A trail of ruffed grouse tracks in the snow led me to the spot where two grouse had bedded down for the night behind a fallen tree. With snow too shallow to burrow into, this was as protected a location as they could find. More often than not, a grouse defecates in its night roosting site before leaving in the morning. Grouse scat comes in two forms, one a dry, fibrous cylindrical pellet with a white-wash of uric acid at one end, and the other a softer, darker brown plop. The vast majority of a grouse’s diet (buds, twigs, leaves, catkins) goes directly through its digestive system and forms the dry, courser scat. Finer (and more nutritious) material such as the cambium layer of woody plants enters the caeca, two specialized pouches, before passing through the large intestine. The caeca contain bacteria which break down cellulose and produce the more digested, and therefore more liquefied, scat. Sometimes the two kinds of scat are deposited separately and sometimes, as in the bed on the right in the photograph, together. (Thanks to Dr. Alcott Smith who clarified grouse digestion for me.)

Moose and White-tailed Deer Track Comparison

1-29-13 deer & moose track IMG_2286Even with the knowledge that the moose is the largest member of the deer family, the discrepancy between the size of its hoof and that of a white-tailed deer’s is impressive. A moose’s front foot track is somewhere between 4 ¼ ” and 7” long, whereas a deer’s front track is between 1 ¼ “ and 4” long. Both have hooves that are heart shaped, and point in the direction of travel. Deer are more hindered by snow than moose, so finding a deer taking advantage of a moose’s trail by stepping directly in the moose’s tracks (see photo) makes perfect sense. (The moose’s foot was dragging as it stepped into the snow, thus causing the groove that leads to the track.)

Sharp-shinned Hawk

1-25-13 sharp-shinned hawk2 IMG_1977If the majority of your diet consisted of one type of food, and that food was concentrated in certain spots, it would make sense to frequent those spots. Bird-eating predators, such as the sharp-shinned hawk, are frequently seen at bird feeders for this very reason. Although not very large — roughly the size of a blue jay (the female is a third again larger than the male) — this accipiter is a formidable predator, and one which causes feeder visitors to either disappear or become motionless for a considerable amount of time. The sharp-shinned hawk is the smallest hawk in North America and derives its common name from the sharp-edged “shin” on the lower part of its legs. Its long tail and short wings make it extremely adept at flying through dense woods in search of small birds.

Bird of Prey Kill Site

1-24-13 bird of prey kill by SRichards IMG_6546Dramatic stories are not limited to the snowy woods of northern New England! This photograph was taken in Jamaica Plain, a neighborhood of Boston, Massachusetts. It tells the story of a small bird being killed by a relatively small bird of prey, most likely a Cooper’s Hawk or a Sharp-shinned Hawk – both are accipiters and predators of small birds (as well as other prey). Because their wingspans overlap, there’s no way to unequivocally state which of these raptors left this imprint, but whichever it was, it was successful, judging by the feathers and blood that remain. Both of these hawks are listed as Massachusetts Species of Special Concern, with the Sharp-shinned hawk sighted most often in the western part of the state. (Photograph by Sadie Richards)

Downy Woodpeckers Drumming

1-24-13 downy woodpecker3 IMG_7588Non-vocal communication between birds of the same species has become apparent in the last week or so — downy woodpeckers have started to hammer out bursts of steady staccato drum beats on nearby trees. Both male and female woodpeckers drum year round, but they do so most intensively from January to May, especially during the courtship and early nesting season which begin in March. Woodpeckers drum for a variety of reasons: defending territory, attracting a mate, maintaining contact with a mate, signaling readiness for copulation and summoning a mate from a distance. Woodpecker pairs do engage in duet drumming , which is thought to play a role in nest site selection and in promoting and maintaining the bond between mates.