The purpose of this feature is to give scout leaders, educators and naturalists an idea of some of the natural events coming up each month. We will try to cover a variety of natural events ranging from sky events to calling periods of amphibians, bird and mammal watching tips, prominent wildflowers and anything else that comes to mind. We will also note prominent constellations appearing over the eastern horizon at mid-evening each month for our area for those who would like to learn the constellations. If you have suggestions for other types of natural information you would like to see added to this calendar, let us know!
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Notes and Images From October and November 2016
Okay, the joke goes like this. A vulture decides to skip the tedious flight south and take a commercial airline flight instead. Packing a dead chicken for a snack, he heads to the airport. The ticket agent asks, " Would you like to check that bag, sir?" "No," the vulture replies, "It's carrion" (drum roll, cymbal).
I first began to appreciate vultures when I learned to fly sailplanes. In light of that, I should begin this story when I was 16 years old and came across a National Geographic article called "Sailors of the Sky." The author wrote about discovering the world of soaring and his quest to fly cross-country. I was struck by the beauty of the sailplanes and the stories of circling high above the countryside with hawks off the wingtip. My chance to fly didn't come for eight more years, when I discovered the small gliderport in Eagleville, Tennessee. But more on that later.
New World Vultures are in the family Cathartidae. The family name comes from the ancient Greek word meaning "purifier" and shares the same roots as the word "cathartic." Even those who cannot admire the bird must appreciate its importance in cleaning and recycling. But beauty is in the eye of the beholder. The odd-looking, clumsy bird on the ground is transfigured in flight. If you want to see true mastery of soaring flight, just spend some time watching vultures.
Both species are well adapted for soaring flight. This type of flight is gravity-powered. Adaptations include a broad wing with low wing-loading. The low wing-loading allows the vulture to have a low sinking speed, and to maximize its time in the air. The separated primary feathers at the wingtips increase the efficiency of the wing for low speed flight. The higher drag associated with this type of wing does not hurt the foraging ability of vultures. Pursuit is not required.
The glide ratio of a Turkey Vulture is said to be around 15:1, so for ever 15 feet it flies horizontally, it sinks 1 foot. There are other birds which have higher glide ratios, notably the Wandering Albatross, with a glide ratio of 20:1. But the vulture's glide ratio suits its lifestyle.
The Turkey Vulture is the larger of the two species. It's about 26 inches tall and has a wingspan of around 67 inches. Weight is about 4 pounds. In flight, Turkey Vultures hold their wings in a distinct dihedral (V-shape). They also teeter from side to side. Black Vultures have a much shorter tail, don't teeter from side to side, and have whitish patches at the wing tips. Black Vultures are about 25 inches tall and have a 59 inch wingspan. Black Vultures tend to flap more than Turkey Vultures, and their wing beat is shorter and more "floppy" looking. Though Black Vultures are smaller than Turkey Vultures, they weigh more and dominate Turkey Vultures at feeding sites.
Both soaring birds and sailplanes are always moving down relative to the air around them. To climb, you must find a pocket of air that is rising fast enough that it carries you up with it, much as a bit of ash is carried up by the hot rising air over a barbeque grill. With thermal soaring, the Sun warms the ground enough that the air above it warms up, expands, and then rises in a column.
Hawks, vultures and sailplanes circle in the column of rising air and are carried upward. Soaring birds and sailplanes also use wind that is deflected upward by ridges and mountains to gain altitude. But soaring is possible on windless days. A vulture can gain altitude in one thermal, then fly cross-country to another, making its way across the countryside using the thermals like you would use stepping stones to cross a brook.
Turkey Vultures have a lower minimum sinking speed than Black Vultures. This may explain why the Turkey Vulture's summer range extends much farther north. Even though the Sun is not as efficient in heating the ground at more northern latitudes, the Turkey Vulture's relatively lower sink rate allows it to stay aloft.
Unlike, Black Vultures, Turkey Vultures use their sense of smell in locating food. Often we see Turkey Vultures hunting low to the ground. Their longer tail seems to give them a superior ability to handle high winds, and they seem to do that effortlessly.
Both of these species don't build nests, but tend to occupy cavities like hollow trees and stumps. Also used are caves, deep crevices on cliffs and man-made structures. They form long-term monogamous relationships according to The Sibley Guide to Bird Life and Behavior, but may pair again upon the death of a mate.
As I said at the beginning, I first started learning about birds of prey from the cockpit of my LS1-f sailplane. It was not unusual to find a vulture or a hawk circling in the same thermal as I was. Probably because they forage at a higher altitude, I flew more often with Black Vultures than with Turkey Vultures. Often I would find them even at cloud base, thousands of feet above the ground.
Soaring in its truest form is really a dance with the wind. To do it well, you have to know how to read the clouds and fronts. On a really good day, you get spectacular views of the landscape below. There is no engine roaring away, just the sound of the wind slipping by. It's a wonderful feeling when you are gliding fast across the landscape and you feel the tell-tale bump of the plane entering rising air. Sometimes you can tell which way to turn by which wing was raised by the lift, sometimes it's just a guess.
If everything goes right, you slow from cruising speed into your minimum sink speed in one long curving pull up, and you find yourself perfectly centered in the core of a thermal. The needle of the rate-of-climb indicator, called a variometer in sailplanes, swings up to a positive rate of climb. The patchwork fields pirouette below, and the altimeter slowly winds up as you gain altitude. When you top out in the thermal, you quickly accelerate to cruise speed and set out again on course. There's a rhythm to it - it's a dance.
One of the facts of life for cross county sailplane pilots is the possibility of an outlanding. Though sailplanes are designed to be highly controllable and to land without taking up too much real estate, landings away from an airport never feel routine.
My sailplane was a wonderful flying machine, with a glide ratio of 38:1. That meant that if I was a mile high in perfectly still air, I could glide 38 miles. But sometimes even that was not enough to get back to an airport. If you make one bad decision you're probably okay. Make two, and things get a little more dicey. Make three and you're probably going to be looking for a place to land, and it's going to be someplace interesting.
There's always the possibility that you will damage the plane, no matter how carefully you set up the landing. There are sometimes unpleasant surprises that become visible as you turn onto final approach that you didn't see on the downwind and crosswind legs. Perhaps it was a shallow ditch, a small tree line that didn't show up, cattle that somehow escaped your notice, or a downhill slope.
When I dreamed about sailplanes as a teenager, I had a pretty unrealistic view of outlandings. In my fantasies I'd put the plane down in an impossibly small field, stopping inches from a stone wall, impressing everyone near or far. This is not the way real outlandings work. Again, if you have to make an outlanding you've made at least one, and probably several, really dumb decisions. The images shown at the Mount Mitchell Golf Course were made after I pushed too hard to make contact with the primary mountain wave from Mount Mitchell. I arrived too low and couldn't manage to climb up into the wave.
From the Marion, North Carolina airport, you have to cross over the Blue Ridge Parkway to get to the area, and I was low enough to have to fly though a mountain pass to do that. Below was a large area where there was nowhere to land other than the golf course. I landed on a par 5 hole, but about a third of the way down the fairway was a line of trees that I had to get over. The plane handled well, however, and I rolled to a stop without alarming anyone. Later in the week I climbed to 23,000 feet above sea level, and qualified for my Diamond Altitude Badge.
On this particular day, however, my flying was over. I had to disassemble the plane and get someone to bring the trailer to take it back to Marion. Unlike the people in my teenage fantasies, most people you meet on an outlanding think you're a bit daft. Although they tend to be very kind and understanding, you always seem to have to answer the inevitable question, "Did the wind quit on you?"
'The only people that you can count on impressing with an outlanding are any kids on bicycles that happen to see you land. If you offer to pay one of them a bit to watch the plane while you make a few phone calls, you usually have a happy kid.
That's where we come back to vultures, particularly Black Vultures. More than once they've saved me from having to land out. For all of the instrumentation I had on my sailplane, Black Vultures were much better at finding thermals than I was. At the end of a task, on a final glide where you're starting to see entirely too much detail in the trees below, spotting a gaggle of vultures can be your ticket home. They don't seem to mind the long-winged white bird that pulls in beside them. You are the beginner - they are the experts. For a few seconds you don't feel anything, and then there it is. A bump, then another, then the needle of the variometer rises up to zero, and then starts to indicate climb. You gingerly center the thermal and try to be patient as you gain a few feet with each circle. Then, as the light starts to fade, it's time for the long glide home.
Sky Events for December 2016:
The Geminid Meteor Shower peaks on the evening of December 13th. A full Moon will tend to wash out the sky and make fainter meteors harder to see. TheWinter Solstice, marking the beginning of winter in the Northern Hemisphere, occurs at 4:44am CST on the 21st.
Bright Venus sets in the southwest about three hours after sunset at the beginning of the month. It will gradually set later and later after the sun as the month progresses.
Mercury will reach greatest elongation from the Sun on December 10th. Look for it low in the southwest, below and to the right of Venus. A good time to begin looking for it is about 30 minutes after sunset. A flat southwest horizon will help, as will binoculars.
Mars makes its way from Capricornus into Aquarius this month. Look for it about 35 degrees above the southern horizon at dusk. By the end of the month the apparent size of Mars will shrink to less than 6 seconds of an arc in diameter, making telescopic detail hard to see.
Jupiter rises about 2:21am CST at the beginning of the month in Virgo.
Saturn is in Ophiuchus this month. Though it appears too close to the Sun to see most of the month, you may be able to spot it low in the southeast towards the end of the month. Try about 30 minutes before sunrise.
Constellations: The views below show the sky looking east at 10:00pm CST on December 8th. The first view shows the sky with the constellations outlined and names depicted. Star and planet names are in green. Constellation names are in blue. The second view shows the same scene without labels.
Look for the bright stars Castor and Pollux in the constellation of Gemini, The Twins. Compare the colors of the bright stars Betelgeuse and Rigel in Orion. Betelgeuse is a red giant and Rigel is a very hot, blue-white supergiant. If you have a telescope or binoculars, look at the center of the three "sword" stars below Orion's belt. There you will find the Orion Nebula, M42, one of the most magnificent emission nebulas in the sky. The pink glow of hydrogen alpha light is visible only in very large telescopes and the nebula appears as a small greenish glow in small telescopes. Crouching beneath the feet of Orion, is Lepus, the Hare. Sirius, the brightest star in the sky, shines below Orion. Sirius is in Canis Major, the Great Dog, and for that reason is known as the Dog Star. In the late summer, Sirius rises at the same time as the sun. Because of this, the late summer days are known as the "dog days." The faint constellation Monoceros, the Unicorn, follows Orion over the eastern horizon. Low in the eastern sky below Gemini is Canis Minor, with its bright star Procyon. Procyon means, "before the dog," and refers to the fact that Procyon rises just before the Dog Star, Sirus. Look below Gemini and see if you can spot the faint glow of M44, the "Beehive Cluster." This cluster is located in Cancer, the Crab.
On Learning the Constellations: We advise learning a few constellations each month, and then following them through the seasons. Once you associate a particular constellation coming over the eastern horizon at a certain time of year, you may start thinking about it like an old friend, looking forward to its arrival each season. The stars in the evening scene above, for instance, will always be in the same place relative to the horizon at the same time and date each December. Of course, the planets do move slowly through the constellations, but with practice you will learn to identify them from their appearance. In particular, learn the brightest stars (like Sirius and Procyon in the above scene), for they will guide you to the fainter stars. Once you can locate the more prominent constellations, you can "branch out" to other constellations around them. It may take you a little while to get a sense of scale, to translate what you see on the computer screen or what you see on the page of a book to what you see in the sky. Look for patterns, like the three stars in a line in Orion's belt.
The earth's rotation causes the constellations to appear to move across the sky just as the sun and the moon appear to do. If you go outside earlier than the time shown on the charts, the constellations will be lower to the eastern horizon. If you observe later, they will have climbed higher.
As each season progresses, the earth's motion around the sun causes the constellations to appear a little farther towards the west each night for any given time of night. If you want to see where the constellations in the above figures will be on January 15th at 9:30pm CST, you can stay up till 11:30pm CST on the December 15th and get a preview. The westward motion of the constellations is equivalent to two hours per month. For instance, if you want to see what stars will be on your eastern horizon on March 15th at 9:30pm CST (3 months later), you would need to get up at 3:30am CST in the morning on December 15th (3 months times 2 hours/month = 6 hours).
Sky & Telescope's Pocket Star Atlas is beautiful, compact star atlas.
For skywatching tips, an inexpensive good guide is Secrets of Stargazing, by Becky Ramotowski.
A good general reference book on astronomy is the Peterson Field Guide, A Field Guide to the Stars and Planets, by Pasachoff. The book retails for around $14.00.
The Virtual Moon Atlas is a terrific way to learn the surface features of the Moon. And it's free software. You can download the Virtual Moon Atlas here.
Cartes du Ciel (described in the monthly notes above) is a great program for finding your way around the sky. It is also free, and can be downloaded here.
Apps: We really love the Sky Safari 5 Pro. It is available for both iOS and Android operating systems. There are three versions. The Pro is simply the best astronomy app we've ever seen. The description of the Pro version reads, "includes over 27 million stars, 740,000 galaxies down to 18th magnitude, and 620,000 solar system objects; including every comet and asteroid ever discovered."
For upcoming events, theSky Week application is quite nice. Available for both I-phone and Android operating systems.
Another great app is the Photographer's Ephemeris. Great for finding sunrise, moonrise, sunset and moonset times and the precise place on the horizon that the event will occur. Invaluable not only for planning photographs, but also nice to plan an outing to watch the full moon rise. Available for both androids and iOS.
December really marks the beginning of the breeding season for our Tennessee frogs and toads. We have had breeding choruses of Upland Chorus Frogs as early as December 4th. Breeding even before Wood Frogs, these irrepressible inhabitants of flooded winter fields and other wet areas will call throughout the cold winter months. Listen for their call, which sounds like someone dragging their thumb across the teeth of a plastic comb, on mild wet winter evenings. Listen also for Southern Leopard Frogs. We hear them throughout the fall. Many other Tennessee frogs and toads can be seen on mild December nights, but most are silent.
Recommended: The Frogs and Toads of North America, Lang Elliott, Houghton Mifflin Co.
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Natural Calendar December 2013
Nature Notes Archives: Nature Notes was a page we published in 2001 and 2002 containing our observations about everything from the northern lights display of November 2001 to frog and salamander egg masses.
Night scenes prepared with The Sky Professional from Software BisqueAll images and recordings © 2016 Leaps.