The word solstice means sun (sol) stops (stice). It refers to the sun stopping its march south on the horizon where it rises and sets. December 21/22 is the solstice date most years, but there is less than one minute difference in day length for
Take the time to look to the north at on sunny days to observe the super-deep blue skies caused by the lowest sun angles of the year and the low humidity. Because the sun is so low in the sky at , the angle of its rays reaches deepest into homes from south-facing windows this time of year, which is the principle used to heat passive solar homes.
Around sunset, Orion’s rising in the east is always cause for celebrating and easy to pick out. Orion’s belt rises as three vertical stars, with the orange-ish Betelgeuse (pronounced beetle juice) framing the belt on the lower left and the bluish Rigel on the upper right of the rectangle. Soon to follow is the brightest star in the sky, Sirius. Andromeda is high overhead, with the “diamond” of Pegasus high in the west. Also overhead is a double open star cluster, beautiful through binoculars, located midway between Perseus and Cassiopeia, and nearby, the recent astronomical phenomenon: comet Holmes. Discovered in the 1800’s after it flared into naked-eye visibility from its orbit between Jupiter and Mars, comet Holmes has once again flared up inexplicably, possibly caused by a collision with an asteroid. While it is fading back into obscurity, a pair of binoculars or a telescope will reveal the halo of cometary debris that surrounds the core--the tail’s diameter currently exceeds the diameter of the sun. For sky maps pinpointing its location, check out www.spaceweather.com or www.skyandtelescope.com.
Down on the ground, nature has prepared for the sun’s shorter, lower treks across the sky in a myriad of ways. Most people know that mammals prepare for colder temperatures by growing thicker coats of hair, but few are aware of how elegantly this is done. The winter coats of mammals generally have two layers. The outer guard hairs are longer and have and oils that shed water and allow them to slip through brush easier. The inner layer of mammal fur is called the underfur and is soft, thick and downy. Fur can be so insulating that snow can remain on a back without melting.
Will we get snow this December? Snow has a way of transforming the landscape. Wildlife activities are easier to track after a snow; property lines disappear, and the land seems reconnected under the unifying blanket. Snow reflects sunlight away from the ground, making the air colder than it otherwise would be. Why is snow white? Because the millions of edges break the reflected sunlight into all colors of the spectrum, and a mix of wavelengths result in us seeing white. When it’s sunny, look at the shadows of a snowdrift and see how blue it is – like the sky. Ever notice how snow blowing across the road or snow field looks like wispy cirrus clouds? The reason is that cirrus clouds are gusts of ice crystals blowing in the upper reaches of the troposphere.
When ice forms on lakes, creeks and rivers, some wildlife get water by eating snow, but if there is none, the cold weather ice concentrates their numbers as they move toward larger bodies of water for drinking. Eagles move from
Many over-wintering birds have gathered into mixed species flocks, which many an Audubon member can attest to at their well-stocked bird feeders. Crows, in contrast, join together in single species flocks. Many raptors can be seen by the roadside, perched in trees looking for food. Most are red-tailed hawks. (Look for the rust-colored tail, dark head and light breast). And, of course there are the flocks of waterfowl at area reservoirs, most visible around sunrise and sunset.
This is a great time of year to take a hike in the woods to enjoy the still-green green briar vines, the “blooming” mosses, the orange bittersweet fruit, and, of course, to look for signs of wildlife. Among those many signs are the piles of sticks against trees – pack rats! Saplings stripped of bark and bare patches of earth are signs of the recent deer mating season. Look for rabbit and deer-pruned twigs from last year’s succulent new growth on shrubs. Squirrels have been known to eat bark and tap the sap of the maple in a hard winter. With the reduced osage orange and acorn production caused by the late spring freeze last April, expect more competition at the bird feeders!
Finally, the prairie grasses have lost much of their seed heads by December, and grasses are increasingly matted down by ice, snow and rain as the dormant season progresses. You can still find green shoots of wild onion, yarrow and rosettes of mullein, daisy and thistle, with the onion almost always grazed down a bit by a hungry rodent or deer. Speaking of rodents, look for a tallgrass bunch that has been chewed off a few inches up from the ground by a nest building rodent who will use the straw for insulating its over-wintering burrow. One of my favorite winter-time hiking activities is to find a patch of tallgrass grasses on a cold but sunny day and lie down into the grasses, creating a nest that protects me from the wind and is open to the sun. It is amazing how comfortable this can be. I’m too big to nestle into an Eastern red cedar tree, but many a small bird can attest to its value as a wind break and heat retaining structure on a cold night!