Natural Calendar February 2012

Natural Calendar - February 2012

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 January 2012

Upland Chorus Frog, Pseudacris feriarum, Nikon D40x and 105mm Lens

The Lover of the Festival: With the mild and wet weather conditions this January, the Upland Chorus Frogs at our farm have been calling night and day. The scientific name for the Upland Chorus Frog is Pseudacris feriarum. "Feriarum" is Latin for holiday, festival or leisure time. In any case, this species does like to "party hardy" and choruses, once started, can go for days or weeks on end, if not interrupted by colder temperatures.

Even then, these little frogs do not give up easily. We have one record of an Upland Chorus Frog calling on a morning where the ground was covered with frost and the air temperature was a measured 29 degrees Fahrenheit. A cold front had passed through the night before and the water had still not yet frozen. It was calling very, very slowly. The calls of this frog, and our other two Pseudacris species, Mountain Chorus Frog and Spring Peeper, are a welcome part of the winter landscape of Tennessee.

Jupiter & Europa, January 5th, Point Gray Flea 3 Video Camera and 20 Inch Newtonian Reflector. Europa is partially eclipsed by Jupiter's shadow.

One fun part of observing the planet Jupiter is the constant dance of the four Galilean moons. They change position constantly in relation to the planet, transiting across the face of Jupiter or being eclipsed by its shadow.

On January 5th I caught the moon Europa emerging from behind the great planet. Because sunlight is coming from the right as you view the image, the shadow cone of Jupiter is displaced to the left of the planet. Europa appeared for about 5 minutes before being eclipsed by Jupiter's shadow. The image at right shows Europa about halfway into Jupiter's shadow. In recent years Europa has been viewed as a favorable habitat for life due to the probable existence of liquid water beneath it's frozen surface.

Sky Events for February 2012:

Evening Sky:

Look for bright Jupiter at the beginning of the month in Aries. The great planet is about 57 degrees above the southwest horizon as the evening begins. Binoculars will show the Galilean moons if you hold them steady.

Venus shines brilliantly in the southwest after sunset. At magnitude -4.1, it is the brightest star-like object in the sky.

Mars rises about 8:17pm near Leo the Lion's rear foot at the beginning of the month. The red planet is steadily brightening, and will be at magnitude -1.2 by month's end. Mars is coming to opposition on March 3rd and will be closest to Earth on March 5th. In February the apparent diameter of Mars increases to 13.8 seconds of an arc. This is a good time to get a telescopic view of the planet. If you do, waiting until the planet is due south and has reached its highest elevation above the horizon will give you the best chance of seeing details.

Saturn on January 29th, Point Gray Flea 3 Video Camera and 20 Inch Newtonian Reflector.

Saturn rises about 11:16pm at the beginning of the month, and will be in good position to view in the predawn sky before sunrise. It rises near and a little below the bright star Spica in Virgo. Saturn will be the brighter of the two objects. The rings are now open to 15 degrees of tilt. Just about any telescope will give a stunning view.

Mercury will gradually slip into view in the western sky after sunset late in February. Look for it beginning about 30 minutes after sunset from February 22nd on through the end of the month. You will need a flat western horizon. Binoculars will make it easier to spot, but make sure the sun has completely set before using them. Permanent eye damage can occur if you happen to sweep onto the sun with binoculars.

All times noted in the Sky Events are for Franklin, Tennessee and are Central Standard Time. These times should be pretty close anywhere in the mid-state area.

Constellations: The views below show the sky looking east at 9:30pm CST on February 15^th. The first view shows the sky with the constellation outlines and names depicted. Star and planet names are in green. Constellation names are in blue. The second view shows the same scene without labels.

Messier 81, February 18th and 19th, 2010, 6" Apochromatic Refractor and ST-2000XCM CCD Camera. Total Exposure Time 6 Hours, 40 minutes.

Leo, the Lion, is prominent with its bright star Regulus. Approaching opposition in March, Mars is growing brighter and glows like a hot coal near the rear foot of the lion. Use Regulus and Leo to guide you to the faint constellation of Sextans, the Sextant.

Conspicuous in the northeast is Ursa Major, the Great Bear. Near the "snout" of the bear lie two great galaxies, Messier 81 and Messier 82. These can be seen as faint smudges in binoculars on a clear night, and observers in pristine skies have even reported seeing a glimpse of M81 with the naked eye.

The constellations of Coma Berenices, Berenice's Hair, Virgo, the Virgin and Crater, the Cup are all just making their way above the horizon and will be seen better next month. If you can't wait, you can always stay up a little later and watch them as they climb higher above the horizon.

February 15th, 9:30pm, Looking East

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 February. 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 Regulus in the above scene looking east), 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 stars of the "Big Dipper."

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 March 15th at 9:30pm CST, you can stay up till 11:30pm CST on the February 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 May 15th at 9:30pm CST (3 months from now), you would need to get up at 3:30am CST on February 15th (3 months times 2 hours/month = 6 hours).

Recommended:

Sky & Telescope's Pocket Star Atlas is beautiful, compact star atlas. It is destined to become a classic, and is a joy to use at the telescope.

A good book to learn the constellations is Patterns in the Sky, by Hewitt-White. You may also want to check out at H. A. Rey's classic, The Stars, A New Way to See Them.

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.

Starry Night has several software programs for learning the night sky. Visit the Starry Night web site at www.starrynight.com for details.

Amphibians:

Crawfish Frog

The amphibian season continues to build in February. One trick to finding amphibians in winter is to go out on mild (50 degrees Fahrenheit or warmer) rainy nights. For safety, it is important that you have another person with you to help watch for traffic as you slowly drive the back roads. Look for things that cross the road in front of you and stop frequently and listen. Early breeding frogs like Upland Chorus Frogs, Spring Peepers and Wood Frogs are already calling by the first of the month. On warmer nights listen for Southern Leopard Frogs. Spotted Salamanders and Tiger Salamanders also breed in January and February, and the eggs of both can often be found this time of year. Towards the end of the month, given mild temperatures, you can sometimes hear American Toads beginning to call. In west Tennessee, Crawfish Frogs give their loud snoring calls starting in late February and continuing on into early March. At higher elevations, listen for Mountain Chorus Frogs towards the end of the month. Remember that on mild nights you may find frogs and toads out foraging that you do not hear until later in the season.

Birds:

Many times when we have been out looking for amphibians in February we've witnessed courtship flights of the American Woodcock. Listen for the "peent" call at dusk and watch as the male Woodcock spirals upward till it's almost out of sight, then dives back to the ground, twisting and turning. For more about watching American Woodcocks see, "The Woodcock's Call."

Red-Shouldered Hawks mate as early as February in Tennessee. Watch for courtship activities of these and other hawks.

Stick Nests: With the leaves down, this is a great time of year to find raptor stick nests. I make notes of all the nests I find and then periodically check them to see if anyone has "moved in." Many times Great Horned Owls make use of an old Red-Tailed Hawk's nest from the previous year. The owls can already be incubating eggs in January. Of the hawks, Arthur Cleveland Bent, in his "Life Histories of North American Birds of Prey," writes,

"[Red-tailed Hawks]...begin their nest building late in February or early in March; I have seen a wholly new nest half completed and decorated with green pine twigs and down as early as February 18th, over a month before the eggs are laid...Typical nests are from 28 to 30 inches in outside diameter, the inner cavity being 14 or 15 inches wide and 4 or 5 inches deep...The nests are well made of sticks and twigs, half an inch or less in thickness, and neatly lined with strips of inner bark, of cedar, grapevine or chestnut, usnea, and usually at least a few green sprigs of pine, cedar or hemlock. Some nests are profusely and beautifully lined with fresh green sprigs of white pine, which are frequently renewed during incubation and during the earlier stages of growth of the young...They "stake out their claim" late in February or early in March...by marking the nest they propose to use with a sprig of green pine...I believe that the birds prefer to build a new nest each year, but they sometimes use the same nest for consecutive years..."

Bent was writing about the Red-Tail Hawks in New England, so our times could be a little earlier.

You probably have already put out your bird feeders, but if you haven’t you're missing out on a lot of good looks at winter feeder birds. This is a great time of year to start learning your birds. Watch and listen for winter residents such as White-throated and White-crowned Sparrows, Yellow-bellied Sapsuckers, Red-breasted Nuthatches, Golden-crowned Kinglets and Brown Creepers.

Recommended:

The Sibley Guide to Birds, David Allen Sibley

The Sibley Guide to Birds of Eastern North America, David Allen Sibley

An inexpensive guide for beginners is the Golden Guide for Birds.