Thursday, December 31, 2009

The Earth Year

On this last day of 2009, it is important to realize that, beyond our home planet, a year, the cherished span by which we measure our history and our lives, is merely a segment of time. And while the duration of a year correlates with the period of Earth's orbit around the sun, the specific timing of man's calendar year is not tied to any natural cycle; rather, it is a product of human culture, influenced by politics and religion.

It might be argued that our year should begin at the winter solstice (the beginning of the solar cycle as perceived from Earth) but that would produce a 6 month variance of the calendar between the Northern and Southern Hemispheres. Of course, were it not for the tilt of our planet's axis, the seasons would not exist and we would not have solstices. If that were the case, the period of sunlight (for any given location) would not vary through the year and humans would likely be fixated on the moon, measuring our lives and our history in lunar cycles.

Beyond Earth, a year has no more significance than, say, 23 seconds, 51 hours or 813 days; it is just our measure of time based on our planet's orbit and on our experience of seasonal change. If we lived on Mercury, our year would be 88 Earth-days long while, on Neptune, an Earth-year would take us only 1/165 of the way around the sun. When viewed from the perspective of our galaxy, a year becomes even less significant as a period of time; it takes somewhere in the neighborhood of 230-250 million years for our solar system to orbit the center of the Milky Way. As in all aspects of natural science, it is important to acknowledge that our perspective, as observers from planet Earth, can temper our understanding of the Universe. Happy New Year!

Tuesday, December 29, 2009

The Threat of Argument

Argument, the unruly and emotionally-charged cousin of discussion, is often triggered by disrespect, intolerance and selfishness. While arguments are common in human relationships, they seem to be an increasingly common form of public interaction, threatening the welfare of society as a whole.

Recent town meetings to discuss health care policy descended into shouting matches, a Congressman became a folk hero by interrupting a Presidential speech to call him a liar and Capitol Hill has broken into polarized camps. All of this is fueled by an increasing assortment of talk media where bombastic moderators (from the left and right) invite guests from the political fringe and encourage heated argument, all the while interrupting with their own self-righteous remarks. In like manner, "reality shows" of courtroom antics and dysfunctional families entertain us with open combat between attention-starved participants, seeking their brief but fleeting opportunity for fame.

While open debate, dissent and calm discussion are essential to the health of democracy, crass and manufactured arguments have no place in government, entertainment or education. Nothing is accomplished, a poor example is set for our children, disrespect and intolerance are encouraged and stress is induced in participants and viewers alike. Unfortunately, an increasingly large segment of society seems to be entertained by this behavior and by the media programming that supports it; for the rest of us, it is time to vote with our ballots and our remotes.

Monday, December 28, 2009

Formation of Waterfalls

Liquid water, acting under the force of gravity, has sculpted spectacular landscapes across our globe and waterfalls are among the most beautiful and inspiring. Most waterfalls develop where a stream passes a geologic boundary, crossing from a hard, resistant bedrock to a softer, less resistant one; this causes an abrupt drop in the level of the stream flow. The "fall line" of the southeastern U.S. offers an excellent example of this process; here, rivers flowing from the Southern Appalachians to the Atlantic all possess significant waterfalls at the boundary of the Piedmont (underlain with hard igneous and metamorphic rock) and the Coastal Plain (composed of soft sedimentary deposits).

Once waterfalls form at these geologic boundaries, they begin to erode upstream and, over thousands of years, produce rugged gorges through the hard bedrock; an excellent example is provided by the Niagara Gorge, which formed (and continues to develop) as the falls cut their way upstream through the Niagara Escarpment. In other areas, waterfalls form when the walls of river valleys are altered by glaciers or landslides; tributaries that once descended through side canyons now drop precipitously to the valley floor; Yosemite Falls is perhaps North America's most spectacular example.

Some waterfalls occur beneath the surface of our planet, developing at sinkholes where the roof of a cave has collapsed. In these karst landscapes, thick layers of soluble bedrock (limestone or dolomite) lie just beneath the surface, often covered by a relatively thin veneer of sandstone. Cracks in the overlying rock allow rainwater and snowmelt to percolate into the limestone, eventually opening vast, underground networks of streams and caves. Surface streams drain toward these sinkholes and, once the underlying cave is spacious enough, a waterfall forms.

Saturday, December 26, 2009

Window on Winter

While I enjoy winter hikes, on days like today, with frigid air and wind-blown snow, a good novel often sounds more inviting. Fortunately, we have a feeder just outside our picture window and the harsh conditions bring a wide variety of birds to the edge of our family room.

Feeding groups of chickadees, titmice, white-breasted nuthatches and downy woodpeckers appear on a regular basis and northern cardinals, especially bright against the bleak, winter landscape, are more than welcome visitors. Now and then, an unruly mob of house sparrows and starlings invades the scene; though not overly fond of the sunflower seed, they are voracious scavengers and, while searching through the contents, scatter much of the seed for our ground feeders. The latter include juncos, white-throated sparrows, cardinals, mourning doves and an occasional fox sparrow. Among other visitors are red-bellied woodpeckers, house finches, purple finches, Carolina wrens, hairy woodpeckers and those erratic red-breasted nuthatches. Of course, gray and fox squirrels grab what they can and, toward dusk, an opossum may wander in to scour the site for fallen seed.

Amateur naturalists and beginning bird watchers are often surprised to discover the variety of birds that inhabit our residential areas. All it takes is a well-placed feeder and cold, snowy weather to provide an entertaining window on nature's diversity.

Friday, December 25, 2009

Christmas Pinwheel

Yesterday's winter storm is centered over Iowa this morning and its counterclockwise winds are producing dramatic and ironic variations in the holiday weather. Strong southerly winds ahead of the storm are pushing relatively warm, moist air far to the north while cold, northerly winds to its west are bringing frigid air to the deep south. At this hour, the temperature in Dallas sits at 31 degrees F while it is five degrees warmer in northern Wisconsin; Chicago enjoys a balmy 42 degrees though, half a State to the southwest, Des Moines shivers at 19.

Northwest of the central low, the warm, humid air is being pushed over the dense, Arctic air, producing heavy snow which, combined with strong north winds behind the cold front, has created blizzard conditions across western Minnesota, the eastern Dakotas and down the Nebraska-Iowa border. Here in Missouri, wrap-around flurries, caught in a gusty, west wind, have arrived just in time for Christmas; the temperature is 17 F and is forecast to remain near 20 degrees throughout the day.

Powerful, slow moving storms often produce a marked contrast in weather over short distances and, as is evident today, one's latitude neither rules out nor guarantees a snowy Christmas. Like giant pinwheels, these massive systems can mix north with south in a sudden and dramatic fashion.

Thursday, December 24, 2009

From April to December

Last evening, as a massive winter storm swirled over the Central Plains, thunderstorms rolled across Missouri, swept northward in advance of the cold front. Dropping torrential rain, the storms were accompanied by balmy, spring-like air and, by dawn, the thermometer sat at 50 degrees F.

Though such balmy interludes are common here during the winter months, the potency of the thunderstorms was a bit unusual, confirming the tremendous amount of energy in this latest storm system; to our southwest, the trailing cold front ignited tornadic supercells in east Texas while, north of the storm, blizzards raged across Minnesota and the Dakotas.

Contrary to the original forecast, the Midwest low has apparently weakened while a secondary low, which developed over Oklahoma, has strengthened, bringing heavy snow to central Oklahoma, northern Texas and southeastern Kansas. As this low tracks northeastward, we will remain in the warm (rainy) sector today but, as its front sweeps in from the west, our temperature will plummet; in concert, snow will develop, northwest winds will strafe the Heartland and December will reclaim Missouri.

Wednesday, December 23, 2009

The Evolution of Thought

Nervous systems first appeared in primitive marine life, billions of years ago. These earliest systems were reflexive in nature; stimuli (light, touch, pressure waves, etc.) would trigger a response (movement toward or away from the stimulus). Such mechanisms were essential to survival, playing an important role in feeding, defense and reproductive behavior.

As evolution produced more complex life forms, the neurological system developed in concert. Special sensory organs permitted more sophisticated forms of sight, hearing, smell and coordination; we can easily identify this progression in the modern representatives of animal families, from mollusks to mammals. Up through birds and most mammals, the neurologic system is primarily limited to peripheral nerves, spinal cord, brain stem and cerebellum; the brain stem controls basic functioning (such as respiration) while the cerebellum is critical to balance and coordination. The cerebral cortex, with its highly complex network of neurons, is the latest product of neurologic evolution, adding the capacity to think, reason, interpret, remember, learn, create and communicate in sophisticated ways.

While a primitive cerebral cortex is found in all birds and mammals, it has reached its highest form of development in primates; of course, humans are the most advanced primates and our cerebrum is, by far, the most complex. Indeed, our brain power has developed to the point where many humans conclude that we are divine creatures, superior to and separated from all lower forms of animal life. Yet, anatomic evidence demonstrates a clear evolutionary progression of the nervous system and medical science has shown a convincing correlation between specific brain injuries (via trauma, stroke, tumor, congenital deformity) and the loss of specific neurologic capabilities. Though difficult for many to accept, our thoughts, memories and emotions are the products of neuronal pathways and brain chemistry.

Tuesday, December 22, 2009

Creeping toward Spring

Now that we have crossed the winter solstice, the Northern Hemisphere begins its long, steady march toward spring. Too slow for many humans, the sun's angle will inch higher in the southern sky and, as a consequence, its rays will more directly impact the lands north of the equator. By the summer solstice, on or about June 21, it will reach its zenith (as our Hemisphere is at its maximum tilt toward the sun) and we will enjoy the longest day of the year.

Though our days will lengthen incrementally, we will not appreciate significant warming for another couple of months; in fact, at central latitudes of North America, the coldest days of the year (by average highs and lows) occur during the third week in January. While the sun angle will be too low to provide significant warming until mid February, we still enjoy balmy interludes as weather systems pump mild air up from the south.

Over time, the frozen ground will thaw, plants will germinate, birds will sing and our faith will be restored. Until then, we can enjoy the snowscapes, star gaze on clear winter nights, listen for the hoot of owls and dream of spring.

Sunday, December 20, 2009

Just House Sparrows

Casual backyard birders know them as those little brown birds that crowd the feeder, aggressively denying access to competi-tors. Avid, experienced birders know that they are "just house sparrows," prolific and alien residents of our cities, suburbs and farmlands.

Actually members of the weaver family, these common birds were introduced to North America from Europe and, to say the least, have adapted well to our natural and man-made environments; though they look and act like our native sparrows, they have shorter legs and thicker bills. Rather dull in plumage and too abundant to interest veteran bird watchers, they are the beneficiaries of farmers and sympathetic suburbanites, who provide them with waste grain, bread crumbs, millet and other commercial bird seed.

While these immigrants have messy nesting habits and compete with native birds for natural food, one must admire their hardiness and adaptability. And, when it comes to their basic physiology and anatomy, they are just as interesting as any other bird species. But looks, habits and country of origin have a lot to do with acceptance, just as occurs in human society.

Friday, December 18, 2009

Merging Lows

Light snow has developed in central Missouri this afternoon as a low pressure trough has dropped down from the north, dragging a pocket of cold air in its wake. Sitting over the mid Mississippi Valley, this low is pulling warm, moist air up from the south and lifting it over the cold air to its north and west. Falling through a thick blanket of subfreezing atmosphere, the precipitation is reaching the ground as snow; since the ground is relatively warm, little accumulation is expected.

Meanwhile, a stronger low is swirling over the Panhandle of Florida, bringing heavy rains to the Southeast. As this low moves to the northeast and our current storm moves to the east, the two systems will merge off the Southeast Coast. Since cold air will drop behind the Midwest low, a cold front will pass through the Mid Atlantic region just as the the storms combine, setting the stage for heavy snow from Virginia to New York.

As with all of these weather events, the track of the heavy snowfall will depend upon the relative positions of the cold front and the new, combined low. If the latter churns slowly to the northeast, paralleling the coast, significant snow will blanket the urban corridor, from Washington, D.C., to New York; if, on the other hand, it's course is more north or more east, the swath of heavy snow will shift accordingly. Either way, its going to look a lot like Christmas across the Mid Atlantic States.

Thursday, December 17, 2009

Geology of Big Bend

Protected as a National Park in 1944, the Big Bend of West Texas harbors one of the best concentrations of geologic formations on the planet. Spanning 500 million years of Earth's history, these rock layers represent the last three chapters of geologic time: the Paleozoic, Mesozoic and Cenozoic Eras.

In the early Paleozoic, some 500 million years ago (MYA), a seaway curved into the south-central region of North America, from Mexico to the latitude of Oklahoma and Arkansas. Over the following 200 million years, this shallow arm of the sea filled with sand, mud and gravel which hardened into layers of sandstone, shale and conglomerate rock. When North America and South America collided during the assembly of Pangea, 300-270 MYA, these sediments were lifted and folded into the Ancestral Ouachitas, which have since eroded into relatively low ridges across this region; stumps of the ancient mountains represent the oldest rocks in Big Bend National Park. About 135 MYA, a broad sea cut across North America, from eastern Mexico to northwest Canada, covering what is now the High Plains and Rocky Mountain corridor; after depositing thick layers of limestone, this Cretaceous Sea retreated, leaving younger sandstones and mudstones (with their cargo of dinosaur and marine life fossils) atop the limestone. The Cretaceous limestone now forms towering cliffs along the Rio Grande River and is the primary component of Big Bend's Deadhorse Range.

Following the Laramide Orogeny (Rocky Mountain uplift, 65 MYA), volcanism developed in the Big Bend region and occurred intermittently from the Eocene to the Miocene (from 42 to 22 MYA). The earliest eruptions formed the Christmas Mountains, in the northwest area of the Park, while later volcanism formed the Chisos Mountains, which include Big Bend's highest point, Emory Peak (7832 feet). Further uplift of the Mountain West during the Miocene has stretched the crust between Big Bend and the Colorado Plateau, triggering formation of the Rio Grande Rift and producing fault-block ranges across West Texas and eastern New Mexico. Finally, heavy precipitation during the Pleistocene molded the varied strata of Big Bend and the dry climate of the Holocene has served to protect and highlight the Park's geologic wonders.

Tuesday, December 15, 2009

Polar Plunge

A dome of cold, dry air has dropped into the Heartland, bringing a morning low of 14 degrees F to central Missouri. Across the Midwest, temperatures range from the teens to 20 below zero, with dew points from the single digits to near 30 below. Sunny skies accompany the dome but the low angle of the winter sun produces little warmth.

Along the southern edge of this dome, from east Texas to the Florida Panhandle, a clash with warm, humid air is producing heavy rain and flooding. Dew points across this boundary rise by 50 degrees in some areas, from the mid teens in Arkansas in the mid sixties along the Gulf Coast. As the dense, cold air knifes below the warm, soupy air, the latter is forced to rise, dropping its temperature below the dew point and triggering the heavy rain. Since the boundary is stationary, this precipitation continues to fall over the same areas and flooding results.

A milder, Pacific high will nudge this dome to the northeast over the next few days and the Midwest should return to more seasonal conditions. But, from now until mid March, these polar outbreaks will invade the Heartland on a regular basis.

Sunday, December 13, 2009

December Sunset

A few days ago, driving south across the flat glacial plain of Illinois, we watched the sun set behind a white sea. The retreating winter storm had spread a few inches of snow on the fields that stretched away to the Illinois River and its backside winds sent ground blizzards across the bleak landscape.

Less than two weeks from its winter solstice, the sun disappeared below the southwest horizon and an orange glow spread above the fields, contrasting with the slate blue of the clear, cold sky; the thermometer read 17 degrees F. Skeins of geese drifted toward the river but nothing else moved in the late afternoon twilight.

Before long, the last glow of dusk retreated with the sun and a bowl of stars covered the vast till plain. It would be a long, frigid night for the wildlife of central Illinois.

Saturday, December 12, 2009

Faith & Courage

There is a well known saying that you will never find an atheist in a foxhole. And, I would add, you will never find an atheist in a suicide vest. Most who engage in combat, for whatever cause, are comforted by the conviction that, should they pay the ultimate price, they will be rewarded in the afterlife. In other words, their religious beliefs, if not their rationale for war, provide the courage to participate.

Humans often lean on faith to deal with a variety of struggles in their lives, including illness, addiction and personal loss; of course, the ultimate certainty of death is the primary threat that we all face. Many would argue that religious belief is an essential source of courage, providing emotional support as we endure the many trials and tribulations of life; were it not for the self-delusion and secondary consequences (discrimination, zealotry, anti-science rhetoric) I might agree that religious faith is a benign form of adaptation.

There is another relationship between courage and faith that most humans are unwilling to consider. Immersed in a world of religious conviction and mysticism, the individual is infused with beliefs at an early age and remains under pressure to retain them throughout his life. It takes courage to question the tenets of faith and, in the end, most choose to comply rather than adopt a life of intellectual honesty.

Friday, December 11, 2009

Ohio Gray

Ohio harbors a wealth of beautiful landscapes: rustic farms, wooded hills, tallgrass prairie, hemlock groves, scenic lakeshores and rugged gorges, to mention a few. But the winter weather of the Buckeye State rarely brings such accolades. Visiting family this week, my memories of Ohio's gray season were strongly reinforced.

Located at the confluence of moisture flow from the Gulf of Mexico and the Great Lakes, Ohio receives more than its fair share of annual precipitation and, during the colder months, what doesn't fall creates a dense overcast of flat, gray clouds. Adding to the moisture flow, the State's terrain gradually climbs toward the east, producing a mild "upslope" as the air rises, cools and condenses. This orographic precipitation is especially evident in Northeastern Ohio where northwest winds, developing behind cold fronts, sweep across Lake Erie, saturate with moisture and dump their cargo of heavy snow on the higher terrain southeast of the Lake.

Of course, this winter precipitation nourishes the rich forests, wetlands, meadows and productive farmlands of the State. But, in the midst of a cold, gray winter, those benefits are often hard to appreciate.

Sunday, December 6, 2009

Myths & Children

For the sake of tradition, we deceive our children with a variety of myths, from flying reindeer to a giant Easter bunny to the tooth fairy. While most consider this practice to be harmless childhood fantasy, stimulating imagination and bringing happiness into their lives, it may produce unintended consequences, if only at the subconscious level.

Would the holiday season be less joyful if we eliminated these myths? Are we unable to celebrate peace, charity and good will without the jolly man in the red suit? Are gifts less appreciated if we are honest about their source? All of this may sound like psycho-babble from a holiday humbug but I'm not sure we need to protect our children from the realities of life by creating fantasies that we must debunk as they begin to mature. Trust is fragile and should be handled with care.

There are certainly good reasons to protect our children from fear and worry during their formative years and their understanding of life must progress in a gradual, non-threatening and age-appropriate manner. But our willingness to sustain traditional myths, however cute and entertaining, says more about our own discomfort with reality than it does about our devotion to childhood fantasy. After all, we have adult myths that are difficult to abandon.

Saturday, December 5, 2009

The Nature of Infidelity

The scandal involving Tiger Woods has flashed across the globe this week, covered by tabloids, sports networks and major news organizations. The fact that Woods, admired for his skill and his devotion to golf, has been unfaithful in his marriage was not a surprise to me. What was a surprise was the that, after centuries of similar episodes, humans were shocked to hear the story.

There is no excuse for infidelity but there are reasons. The first and overriding reason is that human males are not naturally monogamous. Like most males in the animal kingdom, we were designed to spread our genes through as many females as possible; part of that design is a sexual drive that creates interest in having a variety of partners (especially attractive females of child-bearing age). Despite legal, religious and social constraints, many men cannot (or choose not to) contain this natural tendency. Though highlighted by the lives of celebrities, marital infidelity is widespread among all socioeconomic levels, all professions, all religions and all cultures, resulting in a high rate of divorce and the associated painful consequences.

Lesser causes include marital problems, psychological disorders and, far down the list, predatory females (a favorite villain for many unfaithful males). Given the selfish nature of human beings, there are few (if any) ways to prevent the common occurrence of infidelity. But I'm sure that women can suggest a cure.

Thursday, December 3, 2009

Winter Plunges South

The first major cold front of the season pushed through Missouri yesterday morning and, behind the front, strong north winds brought winter to the Heartland. Though temperatures fell through the day, there was not enough moisture in the air to produce rain or snow.

This morning, with a bright full moon in the clear, western sky, the thermometer reads 27 degrees F. Fortunately, the winds have abated and my walk to work in the predawn darkness was pleasantly invigorating. Though cold, the air is dry, offering a welcome change from the chilly, damp weather of recent weeks.

With little solar heating at this time of year, we are at the mercy of the jet stream. Its dips (troughs) allow Canadian air to plunge southward while its northern oscillations (ridges) bring interludes of balmy weather from the south. But the tide has turned and cold spells will dominate for the next few months.

Wednesday, December 2, 2009

Highway Evangelists

The farmers of the American Heartland certainly know a great deal about corn, wheat and soybeans. Many have experience raising cattle, hogs and sheep. Some also fancy themselves as preachers.

Conscious of the captive audience that streams past their fields, these highway evangelists promote their beliefs with a self-righteous zeal. Scripture verse adorns the side of barns, images of Jesus rise above the corn stalks, anti-abortion signs line the fences and makeshift billboards advise us to repent and prepare for eternity.

As private landowners, they certainly have the right to take advantage of the exposure and express their beliefs. Of course, the great majority of these roadside preachers are Conservative Republicans, in favor of the death penalty, opposed to gun control and enraged by any "socialist ideas" that the government might propose; one wonders if Jesus would share their views. And, most disturbing, their underlying message is that America is a Christian nation; all others are unwelcome.

Tuesday, December 1, 2009

Into the Dark

Humans are not naturally equipped to deal with cold or darkness. We do not have enough body fat (in most cases) or hair cover to provide adequate insulation and our night vision is very limited. One can only imagine the stress imposed by these factors prior to the advent of modern technology; death from exposure or nocturnal predators was surely common.

As we descend into the cold and darkness of winter, we get a taste of these environmental threats and, despite our access to electricity and heated homes, we retain the fear of our ancestors, buried in the collective human psyche. We are, after all, tropical creatures, not designed for polar or subpolar climates. And, as a species, we "remember" the advantage that nocturnal hunters have during these winter months; the hoot of the owl and the howl of the wolf, while inspiring, are also chilling.

So, following the lead of our threatened ancestors, we conduct our seasonal rituals. Using lights to ward off the darkness, we pray and hope that our saviour, the sun, will return.

Sunday, November 29, 2009

From Southwest to Northeast

An upper level low is spinning over the Southwest this morning. Attached to a cold front, that stretches from El Paso to Chicago, the storm is pulling in moisture from the Gulf of California, producing mountain snows and valley rains across the Four Corners region; the higher elevations of West Texas can also expect snow from this storm.

Forecast to move eastward and then northeastward over the coming days, this low pressure will begin to tap Gulf of Mexico and Atlantic moisture and drop significant rain across almost all of the East, from the Gulf Coast to New England. Depending upon the relative positions of the cold front and the central low, snow accumulation could be significant in the Northern Appalachians.

Such storms systems, which typically move from west to east across North America, illustrate the dynamics of our weather, combining the effects of wind direction, lift (from both the low and the topography), air temperature and atmospheric moisture; the latter develops as air moves over the ocean or Great Lakes. Contrary to a common perception, these storms are not just a mass of clouds that drop their precipitation as they move across the country; rather, the central low is a pump, constantly mixing the essential ingredients, mentioned above, and interacting with the surface features of our planet.

Saturday, November 28, 2009

The Okavango Delta

Rising in the highlands of eastern Angola, the Okavango River flows southeastward, crosses a sliver of eastern Namibia and enters the northwest corner of Botswana. There, it spreads into a broad, braided delta which, during the cool,wet climate of the Pleistocene, fed a vast inland lake. As the climate warmed, this south-central region of Africa dried out, the lake receded into scattered salt pans and tectonic activity, associated with the East African Rift, altered the regional topography.

Through all of this, the Okavango Delta persisted, draining into the sands and seasonal lakes of the expanding Kalahari Desert; covering more than 6000 square miles, it is the largest inland delta on the planet. Flow through the Delta peaks from May through August, coinciding with the dry season of the surrounding grasslands and desert. As one might expect, this oasis effect attracts huge and varied concentrations of wildlife to the Okavango Delta, moving in from the parched landscape. Just as the Okavango flow begins to contract, in October-November, the wet season arrives on the adjacent plains and the herds disperse from the Delta.

With its slow percolation of fresh water across nearly flat terrain, the Okavango Delta is similar to the Everglades of South Florida, expanding and contracting with the seasons. Outlets to the south and east allow flow to continue through the year, minimizing salt deposition within the Delta; these outlet streams disappear into the sands of the Kalahari or end at saline likes, which, like those of the Great Basin, expand and recede as the balance between evaporation and inflow varies through the year.

Friday, November 27, 2009

The Nature of Parenting

Throughout most of the animal kingdom, parenting does not occur. In "lower animals," up through amphibians and reptiles, fertilized eggs and live young are cast into the world, expected to fend for themselves. With few exceptions, parenting is limited to birds and mammals and, for the most part, it is a maternal responsibility. Encompassing efforts to feed, protect and instill survival skills, the process may take weeks to years, depending on the species.

In mammals, females are instinctively equipped to nurse, protect and teach their young; failure to do so generally implies underlying illness (physical, mental or emotional). In some species, males may take part as providers and protectors but, as we all know, their dedication to these responsibilities is far from reliable. Early humans, like other primates, were likely polygamous and the male's attention to individual sons or daughters was surely lacking. As human society advanced, monogamy has been encouraged through a variety of legal, religious and social pressures and, as a consequence, fathers have taken a more active role in parenting.

As all parents discover, their role is both the most rewarding and the most difficult of human experiences. Due to our large brain, which consumes a large portion of our caloric intake, human children mature very slowly and, though physically capable of producing offspring within fourteen years or so, they require significant parenting themselves for at least two decades. Efforts to prepare them for survival in the modern world is far more challenging than it was in the early centuries of human history. Life, while much easier in some ways, is far more complex in others. Nevertheless, good parenting still comes down to the capacity to love, nurture, protect, teach and let go.

Thursday, November 26, 2009

Thanks to Nature

On this annual Day of Thanksgiving, there are many reasons to be thankful for our natural world. Spectacular sunsets and star-filled skies come to mind, as do mountain vistas, majestic rivers, colorful canyons and beautiful seascapes. And across these varied landscapes is a fascinating diversity of life, from algae to redwoods, amoebae to elephants, krill to blue whales.

Of course, nature is not mindful of our appreciation and does not seek our approval. In fact, we are part of her realm. Nature is both around us and within us; our bodies, minds and souls, like the components of a tree, have evolved from more primitive forms and occupy their unique place on the spreading web of life. Today, we express our gratitude for the experience.

Tuesday, November 24, 2009

Wild Gobblers

As we approach the great American feast day, it seems appropriate to consider the wild relative of our main dish. A native of North America, the wild turkey once inhabited much of the Continent, from southern Canada to Mexico. Extirpated from many areas by over-zealous hunting, our largest game bird has been making a comeback in recent decades, primarily due to habitat protection, reintroduction programs and improved conservation management.

A bit leaner than their domestic cousins, wild turkeys are nearly as large; adult males often weigh 20 pounds or more. Despite their size, these birds are capable of rapid flight for short distances and, equipped with long legs, usually escape predators by running into cover. Wild turkeys favor open woodlands and are best observed near the border of fields and forest. After feeding on acorns, seeds, berries, corn and insects through the day, they roost in trees for the night.

In spring, adult males gather harems of up to fifteen hens; sparring with one another and attracting females with a mix of gobbling, strutting and feathered displays, these males, like American elk bulls, become obsessed with their mating rituals, foregoing food and sleep for days at a time. Females lay an average of twelve eggs in a shallow, concealed depression and incubate them for almost a month; the young poults remain with their mother through the summer, often joining other broods in communal roosts and on favored feeding grounds.

Sunday, November 22, 2009

Raking Leaves

Raking leaves, to the extent that I bother, is one of my favorite forms of yard work; it takes me outdoors, provides exercise, is not terribly exacting and always (by my own choice) occurs on a mild autumn day. Yesterday, with partly sunny skies, a minimal breeze and a high near 60 F, offered a perfect opportunity.

Not inclined toward masochism and dedicated to recycle the leaves to nourish the plants in our yard, I rake them into mounds around the trees or into the shrub and flower beds that line the fences; by mid spring, most have disappeared into the soil. I'm also inclined to stop frequently to take in the sights and sounds of autumn, my favorite season of the year. Yesterday afternoon, the squirrels were busily gnawing on black walnuts, their squeaky efforts ringing through the yard. Woodpeckers were especially active, represented by a pair of downies, several red-bellies, a host of flickers, a hairy woodpecker at the feeder and a lone yellow-bellied sapsucker. The usual mix of chickadees, titmice, cardinals, nuthatches, finches, blue jays and mourning doves also moved through the property, Carolina wrens sang from the wood border and boisterous crows called in the distance.

Even with the frequent, self-imposed distractions, the raking took less than an hour and I found myself looking for other reasons to hang out in the yard on that pleasant autumn day. Then I decided that relaxation, fresh air and a chance to recharge my soul were reasons enough.

Saturday, November 21, 2009

The Nature of Intolerance

Many people...far too many...see this world in black and white. For them, every human idea, trait or point of view is either right or wrong, good or bad, divine or evil; there is no room for dissent, discussion or compromise.

This rigid approach to life is usually ingrained in childhood and reinforced by a cloistered youth, with exposure to a limited circle of relatives and friends. Those who continue to live in such confinement, not motivated to explore the "outside world" via education or travel, tend to retain their simplistic and dogmatic views. In turn, these provincial attitudes foment intolerance, often surfacing as racism, religious zealotry and other forms of discrimination.

Intolerance of other ideas and points of view, a product of early, self-righteous reinforcement by parents or mentors, hinders one's ability to function effectively in relationships and in human society as a whole. Faced with this reality, unwilling to compromise and incapable of trusting "outsiders," such people seek the comfort of like-mined individuals; in this way, intolerance feeds on itself, fringe groups form and the welfare of human society is placed at risk. It is only through education and personal experience, free from religious and political constraints, that we come to appreciate the shades of gray in our lives.

Thursday, November 19, 2009

November Dusk

After nearly a week of clouds, rain and fog, the sun broke through in central Missouri this afternoon and, as the sun set on the western horizon, a clear sky stretched above Columbia; its pale, blue expanse was broken only by a crescent moon to the southwest and sparkling Jupiter to the south. As I trudged home in the fading dusk, it was easy to appreciate that winter is winning its battle with fall.

The cool, dry air was invigorating but the quiet season is clearly taking hold. Sparrows and mourning doves drifted into stands of pine and cedar for the night and only the sharp chirps of cardinals rang through the neighborhood. Squirrel nests, back lit by the red glow of dusk, harbored their industrious tenants while timid cottontails ventured into the fading light for their nocturnal feast; if they escape the gaze of our resident owls, they'll spend tomorrow in their dens.

November takes us from bright October to dark December, from warm days to cold nights. In the Northern Hemisphere, it is, indeed, the dusk of our year.

Wednesday, November 18, 2009

Lowdown on the Leonids

Far from an expert on astronomy, I do try to catch the major meteor showers each year, including the Perseids, in August, and the Leonids, in November. The latter, remnants of the Tempel-Tuttle comet, peak on the nights of November 17-18 and, due to their metallic composition, tend to leave long vapor trails. The Leonids, named for the illusion that they arise from the Constellation of Leo, are especially abundant every 33 years, when the comet has recently crossed Earth's orbit; the shower of 1966 produced thousands of meteors per hour.

This year, a stubborn low, centered over the Midwest, has kept Missouri under a thick overcast, with intermittent fog, cold rain and snow showers. Expected to drift slowly to the east, this weather system should exit our region by the weekend but, by then, the 2009 Leonids will be history.

In fact, I've been unable to observe the Leonids for several years now; whether in Missouri, Colorado or Ohio, the skies have not cooperated. But nature is not in the business of facilitating our plans and, as with many aspects of our lives, luck plays a major role in amateur astronomy.

Monday, November 16, 2009

Snows in the Night

In the midst of a cold, steady rain, the distinctive call of snow geese descended from the skies late last evening. Hitching a ride on northerly winds, they were off to marshlands along the Gulf of Mexico, where they will spend the winter months.

Though I could not see them in the dark, cloudy sky, their calls were no less inspiring and suggested the presence of several flocks, strung out from east to west; eventually, as the travellers moved on to the south, their high-pitched calls faded in the night. While these flocks will escape the Midwest winter, others will follow in their wake, gathering at staging areas along the Missouri and Mississippi Rivers; hopefully, I'll get the chance to visit them before they, too, move on to the Gulf.

Until then, I will listen for other flocks in the night, stirred by the wildness of their collective voice. For theirs is a message of freedom, a call to join them as they follow the sun.

Sunday, November 15, 2009

Prairie Streams

The Great Plains of North America were once covered by a rich prairie ecosystem, which extended from western Ohio to the Rocky Mountain foothills. Today, most of the grasslands have been replaced by cropfields and ranches, significantly diminishing the natural diversity of this region.

Even before the prairies were lost to the farmer's plow and the cattleman's herds, riparian (stream-side) communities were vital to the Great Plains ecology, providing food, shelter, nest sites and natural highways for the varied wildlife of this vast and open country. Now that cropfields cover much of the region, these streams, with their associated woodlands and wetlands, are critical ribbons of natural habitat across an altered landscape; nevertheless, riparian habitats are among our most threatened natural communities, often falling victim to stream diversion and pollution.

Prairie streams concentrate the wild residents of the Great Plains and offer attractive settings for wildlife observation. A wide variety of grassland birds and mammals roost, nest and den along these valleys, which also attract the raptors and carnivores that prey on them. During the spring and fall migrations, these riparian woodlands are ideal for observing songbird migrations and, over the centuries, both wildlife and humans have taken advantage of these bountiful corridors to explore the Heartland and to expand their populations.

Friday, November 13, 2009

Presence of Mind

Brain power is what separates humans from all other species on our planet. This trait, responsible for all of our accomplishments, from articulate speech to flush toilets, has opened our world to discovery and given us the opportunity to understand the complexities of our environment, our bodies and our relationships. It is, after all, the basis for the human condition.

Despite the many advantages that brain power affords, it also has a tendency to complicate our lives. The capacity for memory, essential to the learning process, opens the door to rumination and regret; in like manner, our ability to anticipate the future often leads to worry and dread. Though the past was not as wonderful as we sometimes remember and the future will not be as daunting as we might imagine, these cerebral preoccupations often cloud and influence our present thoughts and actions.

Indeed, in comparison with many others species, humans have a diminished presence of mind. Not endowed with the acuity of sight, smell and hearing that some animals possess, we depend on our higher mental powers to interpret our environment. And, unlike our fellow mammals, we are prone to distraction as the past and future invade our consciousness.

Thursday, November 12, 2009

Starling Ballets

Despised by avid birders and by those who live near their crowded roosts, European starlings have become one of the most successful species in North America, inhabiting almost all of our natural ecosystems. In doing so, they have often displaced native birds by usurping nest cavities or by consuming much of the wild food crop.

Nevertheless, these prolific birds offer some benefits, primarily related to their taste for grubs and other harmful insects. In addition, for those who travel across America's farmlands, they provide entertainment in the form of spectacular aerial displays; these starling ballets are observed during the colder months, when the maligned immigrants gather in huge flocks.

Often first mistaken for a puff of black smoke, the shape of the flock changes constantly as the birds spiral and dip above the countryside, instinctively moving in a coordinated mass. At certain angles, they may disappear from view, suddenly reappearing like a flash card image at a football stadium. To my knowledge, there are no starling choreographers out there but, at times, one wonders.

Tuesday, November 10, 2009

San Rafael Swell

Between Green River, Utah, and the eastern edge of the Wasatch Plateau, 70 miles to the west, Interstate 70 crosses a broad ridge, adorned with spectacular rock formations. This topographic dome, up to 40 miles east-west and 100 miles north-south, is known as the San Rafael Swell.

At the onset of the Eocene Period, almost 60 million years ago, this region was characterized by flat terrain, a subsurface layer cake of Paleozoic and Mesozoic sediments overlying the deep, Precambrian basement. At the surface, early Tertiary deposits lay on successively older rock layers (from top to bottom: Cretaceous, Jurassic, Triassic, Permian and older Paleozoic sediments). Then, during the Eocene, the Precambrian basement folded upward as a broad dome, lifting the overlying layers of rock which have since eroded into the formations that we see today; resistant sandstones and limestones form ridges, domes and pinnacles, separated by valleys of softer shale and mudstone.

Atop the Swell, the Tertiary and Mesozoic layers have been stripped away by erosion, leaving a landscape of Permian sandstone; to either side, the traveller passes through successively younger rock formations as he descends from the crest of the dome to the valleys of the San Rafael River (east) and Muddy Creek (west). Prominent hogbacks (reefs) of Dakota Sandstone, Cretaceous in age, rise along the outer edge of the Swell. By crossing the San Rafael Swell on I-70, we pass through almost 200 million years of geologic history....twice.

Monday, November 9, 2009

Tardy Geese

Most birds migrate in response to the solar cycle, departing their breeding or wintering grounds in concert with a given period of daylight. Waterfowl, on the other hand, tend to move along in response to a combination of weather conditions and food availability; this is especially true during their fall migration when flocks may winter further north if snow and ice are not disrupting their ability to feed.

In Metro Denver, the migrant Canada geese usually arrive during the first week in November, significantly augmenting the smaller populations that are permanent Colorado residents. By now, the fields and skies of the Front Range are usually full of these noisy visitors; in early morning and late afternoon, numerous flocks pass overhead, moving between reservoirs (where they spend the night, safe from predators) and their favorite grasslands. As of today, the influx of migrants has been minimal and I suspect that mild conditions in Canada and the northern U.S. have, as yet, not forced them southward.

Of course, park supervisors and golf course managers hope that they stay to our north, negating an annual cleanup nightmare. But, eventually, the geese will arrive and those of us who enjoy watching their daily travels won't be disappointed.

Sunday, November 8, 2009

Plum Creek Valley

South of Denver, the terrain gradually rises toward the Front Range foothills and the broad Palmer Divide. Drained by Plum Creek and its tributaries, this region has been dissected into a scenic landscape of valleys, ridges and mesas; scrub grasslands cover the lower elevations, juniper and oak thickets adorn the valley walls and stands of ponderosa pine spread across the higher terrain.

Long used for cattle ranching, industry and urban development have spread through the valley over the past century and, in recent decades, suburban sprawl has invaded the uplands. Nevertheless, if one gets away from these sites of human impact, it is easy to appreciate the natural beauty that once characterized all of the Plum Creek Valley. Mule deer are especially common here, feeding along roadways and foraging on the hillsides. Elk winter in the valley and the howls of coyotes echo across this spectacular terrain. Magpies, scrub jays, crows and flickers lend their voice to the wild landscape while golden eagles, prairie falcons, great horned owls and a variety of hawks patrol the region. Though seldom encountered, mountain lions also inhabit the area, attracted by the large deer population.

Such piedmont landscapes, blending the High Plains with the Rocky Mountains, add to the natural diversity of the Front Range environment and offer spectacular settings for wildlife observation. Unfortunately, they also offer appealing sites for residential development and, over time, the natural ecosystem falls victim to human occupation.

Friday, November 6, 2009

Abert's Squirrels

Those who hike in the ponderosa parklands of our western foothills and mesas have a chance to see Abert's squirrels, one of North America's more unique and interesting mammals. Closely associated with ponderosa pine forests, which are best developed between six and nine thousand feet, these "tassel-eared squirrels" are found in the Rocky Mountain chain, from southern Wyoming to northern Mexico, and across the Colorado Plateau.

Best identified by their prominent ear tufts, Abert's squirrels are primarily arboreal, feeding on the seeds, cones, buds and inner bark of ponderosa pines; they also consume a variety of berries, fungi and carrion. Their nests are constructed with pine needles and twigs and are placed high in mature trees, usually at the junction of a large branch and the central trunk. Mating, which follows a day-long chase by several suitors, occurs in late winter or early spring; 2-4 young are generally born in May or June.

The color of Abert's squirrels varies with the geographic area, ranging from gray to dark brown to black, with white underparts. However, on the Kaibab Plateau, north of the Grand Canyon, a subspecies (known as the Kaibab squirrel) has a black abdomen and a totally white tail; long isolated from populations east of the Colorado River, these Arizona squirrels were once considered to be a separate species. Regardless of their location, the population of Abert's squirrels varies with the health and productivity of the ponderosa pine forest, an ecosystem under continuous assault by the invasion of human communities.

Thursday, November 5, 2009

Avian Kites

All across the Great Plains, hawks, gulls and vultures dipped and soared in the deep blue sky on this sunny, November day. Strong south winds, building ahead of the next cold front, triggered the aerial display and pushed summer-like weather into the region.

As expected, red-tails dominated the show but a few rough-legged hawks were encountered on the High Plains and a golden eagle soared above the Palmer Divide, in eastern Colorado. Even the northern harriers and prairie falcons, which typically fly and hunt close to the ground, could not resist a chance to bank and soar with the others. In central Kansas, just east of Russell, a huge flock of sandhill cranes circled high overhead, seemingly making little progress in the stiff, southerly head winds.

While some (if not most) of these aerialists were in the process of hunting, many seemed to be playing in the steady breeze, dipping and gliding above the wide open terrain. If only we had the ability to join them!

Tuesday, November 3, 2009

A Mast Bonanza

Acorns are abundant across central Missouri this year. Well beyond the capacity of natural consumers to eat or store them, the nuts and their fragments coat lawns, roads and walkways.

These nuts are, of course, the fruit of oak trees; more than 600 species of oak can be found across the globe and more than 60 are native to North America. Most oaks are deciduous trees but some, including the live oak of the southeastern U.S., are evergreens; acorn production begins as early as 10 years and as late as 50 years after germination, depending on the species. The white oak family (which also includes bur, gambel, post, chinkapin and chestnut oaks, among others) produce acorns that mature within 1 year and do not have a bitter taste. The red oaks (including scarlet, pin, black, live and willow oaks, among others) produce acorns that mature in 2 years and, due to the presence of tannins, have a bitter taste.

Oaks produce acorns every year but, in mast seasons, which occur every 2-7 years, a dramatic abundance of the nuts are shed; these peak crops result from both innate, natural cycles of the various oak species and seasonal weather variation. This year's mast bonanza will also boost populations of acorn consumers (squirrels, chipmunks, jays, woodpeckers, bears, deer, turkeys, skunks and others) by favoring their winter survival. Native Americans also counted on the mast of autumn and, after leaching tannins from the acorns, would store them for use throughout the colder months.

Monday, November 2, 2009

Big Brother Jupiter

Jupiter shines high in the southern sky during the evening hours this month. More than five times as far from the sun as we are, this massive gas planet has a diameter that is 11 times the diameter of Earth; indeed, Jupiter's size, relative to the sun, is comparable to Earth's size relative to Jupiter. Though mostly gaseous and without a solid surface, Jupiter's mass is greater than twice that of all the other planets combined.

Composed primarily of hydrogen and helium, Jupiter is thought to have a solid core, similar to that of Earth. Its banded atmosphere, composed of ammonia clouds, is colored by varying quantities of sulfides and hydrocarbons and undergoes constant turbulence due, in part, to the planet's high rotational speed (a full rotation occurs within 10 hours). This rapid rotation also induces a bulging of Jupiter's equatorial region, giving the planet an ovoid shape with flattening at the poles. Four large moons, first observed by Galileo in 1610, are accompanied by almost 60 smaller satellites and several faint rings of dust. The Great Red Spot, Jupiter's most famous and recognizable feature, is a giant storm; possessing the diameter of Earth, it has persisted for at least four centuries.

While astronomers have long credited Jupiter with protecting our inner solar system from wayward comets and asteroids (a trait reinforced by the Shoemaker-Levy 9 impacts in 1994), significant controversy surrounds this theory. There is little doubt that the planet's strong gravitational field alters the course of these roaming chunks of ice and rock but Jupiter's ability to absorb them may not exceed its role in tearing them loose from their benign orbits, to send them hurtling toward the inner planets. Like a big brother, Jupiter may be both our protector and our nemesis!

Sunday, November 1, 2009

Nature's Revenge

After more than six months of being contained, trimmed, beautified and doused with chemicals, nature exerts her revenge on the American suburbanite in November. Showering lawns, gardens, roofs and walkways with a copious mix of leaves, twigs and seed pods, she reminds us that manicured landscapes are not her style.

So the fastidious homeowner, intent on maintaining order, must rake, scoop and remove nature's debris. Ever mindful of his watchful neighbors and the expectations of his community, he recycles this "yard waste" in appropriate bags and places them on the curb (in an orderly fashion) for all to see. He is, indeed, a green-minded citizen.

Those of us more accepting of nature's way are slow to respond to this onslaught of plant debris. We know that wind and rain and snow will remove much of it, that mold and bacteria will degrade the larger components and that a variety of creatures (earthworms, moles, mice, squirrels) will make use of its edible contents. We may clean the gutters and rake some areas but will leave most of nature's debris to nourish and sustain the natural landscape and its residents. Of course, some may blow into the lawn master's yard and end up in those bags.

Thursday, October 29, 2009

The Catskills: From Sea to Mountains

During the Devonian Period, 400-350 million years ago (MYA), the shallow Kaskaskia Sea covered much of eastern North America. When the Avalon subcontinent collided with the northeast edge of North America, about 380 MYA, the Acadian Mountains crumpled skyward, stretching from the mid Atlantic region to the Canadian Maritimes. In concert, downwarping of the crust to the west of this range created a deep bay (the Catskill Basin)in the Kaskaskia Sea; known as the Catskill Sea, this deeper water covered much of New York State and northeastern Pennsylvania.

Throughout the remainder of the Devonian and into the Mississippian Period, the Acadian Mountains eroded from lofty peaks to modest hills; much of the erosional debris was carried into the Catskill Sea, gradually filling its basin and pushing its shoreline further to the west (geologists refer to this process as the Catskill Delta formation). Elsewhere, the Kaskaskia Sea retreated to its component basins, which gradually filled with marine sediments and carboniferous deposits (the latter from vast swamplands and coal forests). Then, from 300-250 MYA, Earth's continents merged into Pangea; the collision of North America and Africa lifted the Southern Appalachians and the adjacent Appalachian Plateau. The latter, comprised of sediments that collected in the Catskill and Allegheny Basins, stretches from New York to Alabama (and was once continuous with the Ozarks of Missouri-Arkansas).

The Catskills of New York and Poconos of Pennsylvania mark the eastern end of the Appalachian Plateau and are composed primarily of debris from the Acadian Mountains, now hardened into sandstones and conglomerate rock. Pleistocene glaciers scoured northern sections of the Plateau and its entire length has been carved into a maze of ridges and valleys by a vast network of streams. Composed of more resistant rock, the Catskills harbor the highest elevations of the Appalachian Plateau; Slide Mountain climbs to nearly 4200 feet and almost 100 peaks rise above 3000 feet.

Wednesday, October 28, 2009

Song of the Season

Last evening and this morning, the distinctive song of the white-throated sparrow echoed through our neighborhood. These common sparrows, having bred and summered across the vast North Woods of Canada, winter in eastern and central regions of the U.S., arriving in the latter half of October.

While some move on to the balmy clime of Florida and the Gulf Coast States, our visitors are content to spend their winter in the bleak terrain and harsh conditions of America's Heartland, finding ample sustenance from a wide variety of seeds and berries. After all, they are Canadian natives, oblivious to frigid air and blowing snow. Throughout the colder months, they will be regular visitors to the backyard feeder, scratching for fallen seed during the early morning and late daylight hours.

The homesick song of the white-throated sparrow, translated by birders as "Oh my Canada, Canada, Canada," will fade as winter deepens but will build again during the lengthening days of February; through April, their voice will intensify as these songbirds prepare to depart for their homeland. For now, we welcome their return but know that their tune signals our slide toward winter.

Monday, October 26, 2009

Raw Days

Characterized by chilly, damp and breezy weather, raw days most often occur in early spring or late autumn. During these periods, winter is battling with the milder seasons and frequent Pacific fronts, guided by an oscillating jet stream, bring unsettled conditions.

The raw days occur on the backside of these fronts, as winds shift from the north and "wrap around" precipitation falls under gray skies. The damp chill on these days, usually accentuated by a brisk, north wind, is generally more uncomfortable than the colder but drier days of mid winter. In addition, raw days occur on the heels of a warm, southerly flow (which develops ahead of the front), producing a dramatic, sudden shift to unpleasant weather.

Today is one of those raw days in Columbia. A chilly, morning drizzle has given way to partial afternoon clearing but a high overcast and northwest winds have prevented any significant warming. As the front continues to move eastward, our winds will shift from the south and sunny skies will prevail until the next Pacific front, just three days away, reminds us that winter is lurking to our north.

Sunday, October 25, 2009

The Nature of Teaching

Having spent most of my career in the private sector, I re-entered academic medicine several years ago and have enjoyed the opportunity to teach once again. After all, teachers are among the most influential people in our lives and it has been an honor to join their ranks.

A teacher does far more than impart factual information. In order to be effective, a good teacher guides students through the process of learning: how to acquire information, how to interpret it and how to apply it to their daily lives. The mechanism by which these goals are achieved is, of course, teacher dependent and some are more successful than others.

But the most vital aspect of teaching is the capacity to instill enthusiasm for a given field of knowledge. Looking back over my own education, I can easily name a handful of teachers who were especially effective in this regard and, it seems to me, it was their personal enthusiasm for the subject that infected me and other students. This quality, the essence of teaching, cannot be learned or fabricated.

Saturday, October 24, 2009

Homecoming

It is Homecoming Weekend in Columbia and, though I am not a graduate of the University of Missouri, it is fun to witness the pride and excitement of those who are or will be. Fortunately, mild, sunny weather is forecast for today's festivities and this evening's game.

Unlike our association with religions, political organizations or homelands, university life is an inclusive experience and, aside from alcohol-fueled scuffles at sporting events, is not a trigger for major conflict. Indeed, for many of us, college is our first significant exposure to individuals from other cultures and countries; as a result, our belief systems (religious, political and otherwise) are challenged, forcing us to actually think through the "truths" that were ingrained in our childhood. Since college is also often our first true experience with personal independence, we are free to absorb and consider these viewpoints without the overriding influence of parents and family (however well intended); of course, one hopes that students arrive at this juncture with guiding principles and a moral compass intact.

Though it is seldom helpful to dwell on our past, with its glory and pain, a chance to gather with old friends and share common memories can be a rewarding experience. After all, many of these people were instrumental in shaping our lives and the political climate that encompassed our college years will bind us for decades to come.

Thursday, October 22, 2009

Jim's Lost Season

Like star athletes whose season was cancelled, Jim Cantore and his fellow hurricane stuntmen have surely had a discouraging summer and fall. While global warming is expected to increase the strength and frequency of tropical storms and the annual shot-in-the-dark forecast from Colorado State predicted a fair amount of activity, the Atlantic hurricane season, with just a few weeks to go, has proved to be a dud.

Stripped of their opportunity to report amidst pounding surf and windblown rain, the Weather Channel crew was forced to settle for inland floods and tornado chasing; Jim visited sites of past glory and, in late summer, had the chance to report from a rowboat, gliding above submerged vehicles.

Almost all of this season's hurricane activity was in the Pacific, with several storms threatening the Baja and a series of massive typhoons creating havoc in Southeast Asia. Predicting the pattern and frequency of tropical cyclones is, obviously, still an inexact science. It will be a long winter for Jim and his team, waiting for the 2010 hurricane season to begin in June. As they say in sports, better luck next year!

Tuesday, October 20, 2009

Sirius

This week, in the hour just before dawn, Sirius shines high in the southern sky, just southeast of the Orion constellation. The brightest star in the night sky, Sirius is "only" 8.6 light years from Earth; if it exploded 8 years ago, we won't know until next May.

Actually, Sirius is a binary star system, composed of a large, bright Sirius A star, twice the mass of our sun, and a small, faint Sirius B, only the size of Earth but possessing the mass of our sun. Astronomers believe that the duo formed about 250 million years ago (very recent in the history of the Universe) and that Sirius B, originally a red giant (five times the size of our sun), collapsed into a dense, white dwarf about 120 MYA. The two stars orbit each other every 50 years and are separated by a distance equal to the radius of Uranus' orbit around the sun; of course, from our vantage point, they appear close together.

Also known as the Dog Star, Sirius represented Orion's hunting companion to early human civilizations. Though we now understand its identity and location with more scientific accuracy, it is no less brilliant and no less inspiring.

Sunday, October 18, 2009

Maldivians & Polar Bears

This past week, the governing council of the Maldives, an island chain in the Indian Ocean, planned an undersea meeting to highlight the threat that global warming poses for their island nation. Located about 430 miles southwest of Sri Lanka, the Maldives have a mean elevation below 4 feet, making it the lowest country on Earth. As our planet's climate continues to warm, polar ice will melt and sea level will gradually rise; any low lying, coastal areas will be flooded and, as in the case of the Maldives, become uninhabitable. Furthermore, global warming may have a significant impact on precipitation patterns across the globe, posing a threat to agriculture, ranching and food production.

Like the polar bear of the Arctic, the Maldivian culture may be a victim of global warming, reinforcing the fact that man, like other species, is not immune to natural catastrophe. While current scientific evidence suggests that human activity has played a significant role in the current phase of global warming, Earth's climate has gyrated over its 4.6 billion year history; just within the past 2 million years, continental glaciation has occurred four times and interglacial periods have brought climatic conditions much warmer than those anticipated in the coming decades. Indeed, sea levels have been at least 25 feet higher than they are today.

While we must make every effort to reduce our impact on natural ecosystems, global climate will continue to change, whether induced by supervolcanoes, asteroid strikes, continental drift or fossil fuel consumption. As a consequence, all species, including humans, face potential extinction.

Saturday, October 17, 2009

The Prairie Gull

Nesting in large colonies on prairie wetlands, Franklin's gulls summer across the Great Plains of North America, from central Canada to Montana, the Dakotas and Minnesota. There they feed primarily on insects and continue to do so on their migrations across America's Heartland, often hawking prey above plowed fields and ranchlands.

Those who travel across our vast plains in spring or fall are almost certain to see these gulls, which migrate in sizable flocks and often gather at favored staging areas. Their small size, buoyant flight and preference for grasslands make identification rather easy; Bonaparte's gulls, similar in size and appearance, are common visitors to the Great Lakes region but tend to migrate and winter along the Pacific and Atlantic coasts. By contrast, Franklin's gulls, once called "prairie doves," migrate through the center of our Continent and generally winter south of the United States.

Non-birders and amateur naturalists may be surprised to find these gulls far from any major lakes or rivers. Of course, this reflects the common assumption that "sea gulls" are coastal birds, an image drawn from our trips to the beach. Such assumptions about our natural environment, usually based on limited experience, often prove to be incorrect.

Friday, October 16, 2009

Cranes over Kansas

Venus and a thumbnail moon beamed from the eastern sky as I left Denver early this morning and began a full day journey to Missouri; the first glow of dawn spread across the horizon, lighting a shelf of clouds far to the east. I caught up with those clouds near Flagler and would soon encounter one of nature's annual spectacles, the autumn migration of sandhill cranes.

The first flock crossed I-70 near Goodland and, over the next 60 miles, I observed many others. Nearing Oakley, I saw an especially large flock moving down from the north and I left the highway to observe the birds more closely and, more importantly, to listen to their distinctive calls as they circled southward on a northwest wind; as with the call of snow geese, the rattling bugle of sandhill cranes never fails to stir my soul.

Having summered and raised their young on tundra, marshy grasslands and open woodlands of Canada, these sandhills were headed for wintering areas in New Mexico, West Texas and Mexico; it was my good fortune to cross their path on this bright October morning. Come spring, they will retrace their route to Canada but will stop to rest and feed along the Platte River in Nebraska, a major staging area for North American cranes and an annual destination for naturalists from across the globe.

Thursday, October 15, 2009

Front Range Fox Squirrels

Eastern fox squirrels are native to southeastern and central regions of North America, from southern Canada to the Gulf Coast. Over the years, these adaptable mammals have spread westward, crossing the Great Plains along wooded river valleys, and reached Colorado via the South Platte and Arkansas River corridors; small populations were also introduced in the State's larger cities.

In their native range, fox squirrels feed primarily on mast (acorns, walnuts, hickory nuts, etc.) but also consume a variety of fruits, seeds, buds and bird eggs. The pioneers that spread west did not find an environment rich in mast and have adjusted their diet accordingly, concentrating on alternative food sources (as above); they have also developed a taste for the cambium layer of tree bark and seem to be especially fond of Russian olive and Siberian elm trees (also introduced species). Needless to say, some of their dietary habits have not been well received by Front Range homeowners.

Faced with a large crop of black walnuts, coating portions of our Missouri yard, I decided to bring a couple bucket loads to our Littleton farm, interested to know how they might be received by our local squirrel population. Before I had time to spread them through our wood border, a few of the fox squirrels had invaded the cache and mounds of black pulp appeared across our property; within 48 hours, all of the walnuts were consumed or buried. It was amazing to find that these Colorado fox squirrels, hundreds of generations removed from the eastern deciduous forest, would so quickly (and efficiently) dispatch this gift from their homeland. Instinctual memory runs deep!

Wednesday, October 14, 2009

The Paratethys Sea

During the Triassic Period, some 200 million years ago (MYA), the Tethys Sea opened across Pangea, rifting the northern Continents (Laurasia) from the southern Continents (Gondwana). Over the following Jurassic and Cretaceous Periods, the Atlantic Ocean, Indian Ocean and lesser seaways opened, splitting apart the components of these large land masses and leading to the continental geography that we find today.

During this process, the African Plate drifted northward and rotated counterclockwise, gradually compressing the Tethys Sea and cutting off its eastern connection with the Indian Ocean. In concert, a broad, relatively shallow arm of the Tethys, known as the Paratethys Sea, spread across central Europe and eastern Asia, initially forming a connection between the North Sea and the Mediterranean (the direct remnant of the closing Tethys). Beginning about 40 MYA, compression and subduction along the African-Eurasian margin forced up the Alps and other ranges across the northern edge of the Mediterranean, isolating the Paratethys as a vast inland sea.

Tectonic activity throughout the late Tertiary, followed by periodic glaciation during the Pleistocene, continued to mold the Paratethys Sea as drainage patterns were altered and ocean levels rose and fell. Today, the Aral, Caspian and Black Seas represent remnants of the Paratethys; the first two, entirely cut off from the ocean, have become "saline lakes" while the Black Sea, connected to the Mediterranean via the Bosporus Strait, has settled into a unique, layered hydrology. Cool freshwater, flowing in via the Danube and other Eurasian rivers, overlies warm (but more dense) saltwater that flows up from the Mediterranean; the volume of the latter is balanced by the outflow of freshwater toward the ocean, making the Bosporus Strait a dual flow conduit.

Tuesday, October 13, 2009

October in the Valley

A cool but sunny afternoon coaxed me down to the South Platte Valley for a walk along the river and its wetlands. The recent hard freeze has taken a toll on the fall colors but, on the positive side, it eliminated most of the bothersome insects.

Still a bit early in the waterfowl migration season, the number and variety of ducks won't peak for a few more weeks but a fair mix was present on the river, lakes and marsh-lined ponds. Mallards and gadwall were most abundant, joined in the shallows by small flocks of pintail. wigeon and green-winged teal. Aside from a group of ring-necks, the deeper waters were left to the pied-billed grebes; double crested cormorants were noticeably absent, perhaps spooked south by the recent cold weather. Joining these water birds were great blue night herons, black-crowned night herons, belted kingfishers, killdeer and a lone beaver; cruising one of the larger lakes, the beaver looked more playful than industrious on this sunny afternoon.

Down from the mountains, white-crowned sparrows moved along the wood borders, where a variety of regulars (magpies, flickers, chickadees, song sparrows) made their appearance; American kestrels and a red-tailed hawk rounded out the bird observations. All in all, it was an unremarkable, October afternoon in the South Platte Valley.... just what I needed!

Monday, October 12, 2009

A Persistent Upslope

A shallow but persistent upslope flow has plagued Metro Denver for the past few days. Though the primary storm passed to our north and we were spared the heavy snow, Canadian high pressure, behind the front, has been sweeping cold, relatively humid air into our region; forced to rise across the High Plains, this flow has produced low clouds and fog along the base of the Front Range. Since this cold layer is shallow, a short trip into the mountains leads to clear skies and mild temperatures, offering a convenient escape from our chilly, gray weather.

Today, the wind has shifted from the northeast (the upslope direction for Metro Denver) to the east and the sun is breaking through our clouds and fog. The afternoon temperature should top out near 50 F but enough upslope remains to keep the hazy air in place. By tomorrow, the winds should be more from south and southeast; downsloping across the Palmer Divide, the air will heat up and our persistent fog should rapidly dissipate.

Denver's weather is all about wind direction, which explains both the spring-like outbreaks in winter (brought by downsloping chinooks) and the winter-like conditions in spring (when Pacific storms produce uplsope snow along the Front Range). For now, I anticipate a break in the chilly haze and look forward to a few mild, sunny days before I return to Missouri.

Sunday, October 11, 2009

Shooting the Moon

This past week, NASA bombarded the moon with a projectile, hoping to discover if water lay beneath its dusty, cratered surface. A minor project by NASA standards, the entire mission cost only 79 million dollars.

Not an expert in astronomy, physics or space exploration, I wonder whether the answer to their query, not yet revealed, will be of any significance to those of us on planet Earth. No doubt, the exploration of our solar system and galaxy has led to the development of a vast array of technologies and has given us insight into the evolution of our Universe. NASA advocates are quick to point out that the agency receives a small fraction of the federal budget and that, over the years, our investment has produced significant rewards.

While I cannot disagree with their argument, one hopes that we, as a species, keep our priorities in order. Faced with overwhelming deficits, worldwide famine, antiquated infrastructure and inadequate health care for the masses, the decision to spend 79 million dollars to shoot the moon, though a paltry sum by government standards, seems both unwise and arrogant. Then there's the "defense" budget.

Saturday, October 10, 2009

Driving into Winter

It was chilly and clear in Columbia this morning, with the first frost of the season coating our lawns; the temperature was in the mid 30s (F). Driving west on I-70, the countryside was ablaze with fall colors, briefly obscured by dense fog in the Missouri River Valley. Entering Kansas, cloud cover began to build and the wind shifted out of the north, spinning the turbines west of Salina. Freezing drizzle appeared near Russell and a frosted landscape had developed by the time I reached Wakeeney, persisting to the crest of the Palmer Divide, in eastern Colorado. Approaching Denver, sheets of virga, some reaching the ground as snow, hung along the Front Range and a modest dusting whitened the roofs and lawns of the Mile High City; the temperature hovered in the upper 20s (F).

Despite the bleak landscape and winter-like conditions, I did manage to see an interesting mix of wildlife on my 11 hour journey. Dozens (if not a hundred) red-tailed hawks surfed the wind across Missouri and eastern Kansas while northern harriers hunted low across the icy fields of the High Plains. A flock of white pelicans drifted to the south just west of Hayes, a mix of teal and shorebirds covered many of the farm ponds and a herd of pronghorn browsed the windswept plains near Agate, Colorado. But the highlight of the trip was a large flock of sandhill cranes; numbering 100 or more, they circled across the highway just north of Limon.

I'll spend the rest of the week at our farm in Littleton and, no doubt, we'll be back in mild, autumn weather within a few days. For now, a taste of winter is in order, a common occurrence in October along the Colorado Front Range.

Friday, October 9, 2009

The Nature of Creativity

Creativity is the capacity to innovate: in the ways we express ourselves, interact with our environment, develop products or solve problems. While often associated with art and literature, this trait is important in all fields of human endeavor, including scientific research; indeed, inventors are among the most creative members of our species.

While most humans have some capacity for creativity, there is wide variability among the population. Having exceptional talent in a given area does not necessarily correlate with creativity; a world class musician, for example, may not be creative while the individuals who compose his music or conduct his performance are likely to be exceptionally creative. And, in my experience, creative people have a drive to express this trait in many aspects of their life; it is not unusual to find someone who is both a composer and a painter, both a designer and a photographer, both a chef and a choreographer.

Though a certain level of intelligence is imperative, one's creativity does not necessarily correlate with his or her IQ; a genius may not be creative while very creative people may be of average intelligence. In fact, there is evidence that creativity is not limited to the human species; some chimpanzees, for example, use natural tools, presumably having learned this behavior from creative members of their clan.

Thursday, October 8, 2009

Autumn Clash Zone

In America's Heartland, autumn usually provides a gradual shift from summer heat to winter's chill, offering plenty of sunny, dry weather along the way. But today, those contrasting seasons have been brought together and a clash zone, characterized by thunderstorms and heavy rain, stretches from central Texas to the Ohio Valley.

A broad dip in the jet stream, known as a trough, has produced winter-like conditions across the Intermountain West and Northern Plains while summer heat and humidity have developed across the Southeast. Meanwhile, low pressure, with its counterclockwise winds, sits over New Mexico and high pressure, with its clockwise winds, is camped over the Mid Atlantic region; this combination is pumping warm, humid air up from the Gulf of Mexico and across the Southern Plains and Lower Mississippi Valley. Near the edge of the cold front, this soupy air is lifted, producing the heavy rain and thunderstorms; up to 8 inches of rain is expected in some areas of eastern Oklahoma, southern Missouri and southern Illinois.

Our image of the seasons is based on our observation of weather patterns over many years. We generally picture October as a month of sunny days, colorful foliage and crisp, clear nights. But nature does not always comply with our expectations and this day will look and feel more like April.

Wednesday, October 7, 2009

Leaf Impressions

Back in the third or fourth grade, our teacher asked us to bring in leaves of various colors, shapes and sizes. She then dipped each in paraffin and created an autumn display for our classroom. But the key to this memory was her guide book, which let us identify and label our leaves.

Not having come from a nature-oriented family, this was one of my first introductions to the diversity of plants. At that stage in my life, a tree was a tree and leaves were those parts that shaded our tree house in summer, turned pretty colors in the fall and then cluttered the ground before we raked them into piles or burned them in my grandfather's backyard. And while I was familiar with a variety of wild creatures, primarily from trips to the zoo, I knew them more by category than by species. Backyard birds and butterflies were, in my mind, identified by color, not by family.

I will never know if my teacher anticipated the impact that her project and guidebook might have on her students. Perhaps, for her, it was just another seasonal recommendation in the instructor's manual. But, for me, it was a memorable and significant event, one of only a handful that I can clearly associate with igniting my interest in nature. For that, I am sincerely grateful and hope that others entrusted with the education of children will recognize their opportunity to instill passion in young minds.

Tuesday, October 6, 2009

Humans and Commitment

When humans first evolved, they surely had a strong commit-ment to their families, clans and tribes. After all, they were very dependent on others for their own survival; hunting, food gathering and protection from various environmental threats were all group efforts.

As human culture developed and evolved, these strong ties to family and community gradually loosened and individuals became more independent. Throughout the centuries, in concert with the rise of industry and technology, human commitment has been tested and, as one might expect, fracture lines have developed. Among the examples most often cited is the disintegration of the family, long the cornerstone of human society; one need only look at divorce rates and the growing number of fatherless children to acknowledge that trend.

The relatively recent focus on celebrity, extravagance and globalization has severed some of the last human bonds. Professionals, dedicated primarily to their personal success, change teams or companies with no sense of commitment to their original organization. Financial gurus no longer invest in corporations or small businesses; rather, they trade or buy stocks, puts and options, moving in and out of positions to maximize their personal wealth. Politicians, focused primarily on staying in office, are less concerned about the welfare of the general public than they are about appeasing influential lobbyists; eschewing "socialism," they protect the power brokers of our society. Corporations, uncommitted to the workers that built them, outsource their labor, laying off dedicated employees in order to maximize profits. The commitment of many modern humans is primarily to themselves.

Monday, October 5, 2009

Early Autumn Wetland

After a week of chilly nights and cool days, our local wetland reflects the seasonal change. The goldenrod and other late summer wildflowers are beginning to fade while splotches of olive and rust paint the woodlands. A decreasing variety of birds move about the preserve and, aside from the rant of killdeer, they are mostly quiet.

The water of the seasonal lake has retreated significantly and its resident amphibians, sluggish in the cooling environment, were slow to escape our approach. A lone green-backed heron haunted the wooded shoreline while an increasing number of ducks (primarily mallards and blue-winged teal) fed in the shallows; the latter were joined by a trio of pied-billed grebes, common migrants in our region. Though a squadron of swifts strafed the marsh, our resident swallows were noticeably absent, already off to the warm, buggy south. Out on the mudflats, a pair of yellowlegs joined the noisy killdeer, stopping to rest and feed on their way to southern shores.

A red-tailed hawk circled overhead and a flock of vultures, like kites on a breezy day, dipped and tilted above the creekside ridge. In the coming weeks, the foliage of the marsh and grassland will continue to fade as the surrounding woodlands take on their October splendor; by then, winter songbirds will claim the thickets and the cold, quiet season will settle across this Missouri wetland.

Saturday, October 3, 2009

The Nature of Extinction

Mention extinction and most people think of dinosaurs, picturing them as hapless creatures who could not adapt to their environ-ment. In reality, they were a diverse and highly successful group of animals that inhabited the planet for 160 million years; by contrast, man has walked the Earth for only 125,000 years.

Ever since life evolved in the sea, some 3.6 billion years ago, extinction has played a vital role in our planet's natural history. Genetic mutations produce species diversification which, in turn, leads to competition; through the process of natural selection, those species that are best able to adapt to their environment will thrive while others become extinct. In the great majority of cases, this is a slow, gradual process that occurs over thousands (if not millions) of years. However, natural catastrophes, such as asteroid strikes, super volcano eruptions or other triggers of sudden climate change, can produce rapid and widespread extinctions; often associated with periods of glaciation, these mass extinctions are spaced throughout the history of our planet.

Humans, equipped with superior brain power, have imposed a new wave of extinction. Having directly out-competed Homo erectus and the Neanderthals, we now threaten the survival of other species through destruction of natural habitat, pollution of the environment, over hunting and over fishing. Recent global warming, to which we have clearly contributed, may lead to the extinction of many species and will surely have a negative effect on humans as well. By reducing our impact on natural ecosystems, we should be able to minimize man-induced extinction; nevertheless, natural extinction, essential to the balance of life on Earth, will continue and, at some point in the future, it will claim our own species.

Friday, October 2, 2009

Man and his Planet

Earth coalesced from molten, interstellar debris about 4.6 billion years ago. Within 1 billion years, its crust had cooled into a puzzle of tectonic plates, a mosaic of continents and oceans covered its surface and life had appeared in its primordial seas. It would be another 3.2 billion years before primitive plants and animals colonized the land and almost 3.6 billion years before the first humans gazed upon their home planet.

Throughout that long history of evolution, the tectonic plates have been in constant motion, spreading apart, subducting, colliding and scraping against one another. In concert, oceans have opened and closed, continents have merged and rifted apart and the planet has witnessed an endless chain of tectonic activity, producing volcanism, earthquakes, tsunamis and climate change. All of these events have had an impact on Earth's landscape and on the life forms that inhabit this planet, including humans. Indeed, our species was nearly obliterated by the eruption of the Toba supervolcano, on Sumatra, 74 thousand years ago.

Contrary to the views instilled by various religions, the Earth was not created in preparation for human occupation. We, like other species, evolved in concert with our planet and this evolutionary process, governed by tectonic forces and natural selection, continues today. The log of recent earthquakes, tsunamis and volcanic eruptions clarifies this point and warns us that natural cataclysms, whether along the San Andrea Fault, at Yellowstone or via a wayward meteor, will continue to mold the future of both our planet and our species.

Thursday, October 1, 2009

October Blows In

It felt (and sounded) more like June than October this morning as thunderstorms rumbled across Missouri in the predawn hours. Igniting ahead of a cold front, these storms were racing off to the northeast as our recent, fair weather high slipped toward the mid Atlantic coast. The front itself was back in Kansas, its central low pumping humid air up through the Southern Plains and lower Mississippi Valley.

Tightly wound, the storm system should cross Missouri this evening and our southerly flow will give way to northwesterly winds, ushering in the cooler and drier air that we associate with October. Backside, "wrap-around" showers may persist tomorrow but the coming week promises sunny weather, with highs in the sixties (F) and lows in the forties.

This is, after all, the best month for outdoor exploration across America's Heartland. Mild, sunny days, colorful foliage, waves of waterfowl and energized mammals draw hikers, bird watchers and naturalists into the country. It's the season for adventure, with all its expected sights and unexpected discoveries.

Wednesday, September 30, 2009

Samoa & Sumatra

Over the past 24 hours, powerful earthquakes have occurred along the west coasts of Samoa and Sumatra. A secondary tsunami has caused significant damage in Samoa but it is too early to know if the Sumatran quake will result in a tsunami across the Indian Ocean.

The Sumatran quake occurred south of the epicenter of the devastating earthquake and tsunami that shocked the planet earlier this decade but, like its many predecessors, it surely developed along the west Sumatran subduction trench, where the Australian Plate is dipping below the Eurasian Plate. In such regions, the overlying plate is pulled downward by friction with the subducting plate; this building pressure is intermittently released, producing an earthquake and, by lifting the overlying ocean water, often triggering a tsunami.

The Samoan quake is less easy to explain. Not lying along a plate margin, the Samoan Islands have long been characterized as volcanic hotspots, produced by the movement of the Pacific plate over a mantle plume; in this respect they would be similar to the Hawaiian Ridge and other mid-plate island chains. However, geologists who have studied the age of volcanic rocks on the Samoan Islands and other regional archipelagos, have not found the age progression that typifies a hot spot chain. Some believe that these islands have developed above a fracture in the Pacific plate, which may have resulted from stress within the ocean crust; such a fracture would permit mantle intrusion, leading to volcanism and island formation. Yesterday's earthquake seems to lend support for that theory.

Tuesday, September 29, 2009

Waterpocket Fold

The Waterpocket Fold is a 100-mile long warp of Earth's crust in southern Utah. Trending SSE to NNW, the Fold extends from the Colorado River valley to the area of Thousand Lake Mountain; most of the scenic terrain created by this geologic formation is now protected within Capitol Reef National Park.

Before the Waterpocket Fold developed, rock layers of this region were stacked horizontally, with older sediments below younger ones. Then, about 70 million years ago, pressure within the North American plate crumpled up the Rocky Mountains; in concert, the rock layers of southern Utah warped downward to the east. Subsequent erosion, augmented by uplift of the Colorado Plateau about 15-20 million years ago, has uncovered the various strata of this tilted layer cake, with older sedimentary rocks (Permian; 270 million years old) exposed on the west edge of the fold and younger deposits (Cretaceous; 80 million years old) on the east. Since some layers are more resistant to erosion than others, the Waterpocket Fold is characterized by an alternating pattern of ridges and basins, interspersed with geologic domes and spires.

The landscape that we observe across our globe today is a product of geology, tectonic activity and erosion; it is but a snapshot in the 4.6 billion-year history of our planet and will continue to change over the coming millenia. Few places on Earth offer a better illustration of these natural, terrain-sculpting processes than does the Waterpocket Fold.

Monday, September 28, 2009

The Bird of Autumn

Birders tend to associate certain species with specific times of the year. Of course, this is especially true for those birds that inhabit our area for limited periods of time and the identity of these seasonal species varies widely from one region to another.

Here in the Midwest, most birders likely associate warblers with mid spring, when these colorful and active species move through our region, challenging identification by even the most experienced naturalists. In summer, many of us are especially aware of avian residents that seem undaunted by the heat and humidity; chimney swifts and house wrens come to mind. Winter brings seasonal residents from the north; just the sight or sound of juncos and white-throated sparrows can produce a chilling effect and we come to admire the hardiness of these Canadian visitors.

For me, the white-breasted nuthatch is the bird of autumn. Though this common acrobat inhabits our area throughout the year, I have long associated his distinctive call with cool, sunny days and bright autumn foliage. Perhaps this hearkens back to my earliest days as a birder, when I first identified this amusing bird on a glorious October afternoon. Whatever the cause, the yank of a nuthatch is, for me, a sound of the season, as much a part of autumn as falling leaves, frosty nights and the nostalgic scent of wood smoke.

Sunday, September 27, 2009

Between Seasons

In Missouri, late September is a time of transition. The oppressive summer heat has moved to our south but the deep autumn chill has yet to arrive. Some color dapples the forest but late summer wildflowers still adorn the grasslands and, for the most part, greenery dominates the landscape.

Though a few summer birds have left with the heat, most linger in our woods and winter visitors have yet to leave their Canadian homeland. Frogs, snakes and aquatic turtles still haunt the wetlands, fiddlers still sing through the night and the hoot of the great horned owl is but a distant memory. Here in the Heartland, we are suspended between summer and fall.

But all will change within a few weeks. Autumn splendor will paint the countryside, a hard freeze will silence the insects, waterfowl will reclaim the wetlands and the culling season will begin. Nature may not always obey the human calendar but we can count on her cycle to endure.

Friday, September 25, 2009

The Champlain Basin

When the last of the Pleistocene Glaciers plowed through New England, it molded the landscape, sculpting the mountains and eroding broad valleys. One of the latter, stretching between the Adirondacks of New York and the Green Mountains of Vermont, would become the basin for Lake Champlain.

After peaking in its coverage, some 20,000 years ago, the Wisconsin Glacier began to melt back to the north, opening the newly formed basins. Some of these drained to the south or east, while others, including the Champlain Basin, drained northward. Blocked by the retreating glacier, the north flowing rivers gave rise to valley lakes, filled by mountain streams and by meltwater from the glacier itself. By 15,000 years ago, Lake Vermont, more extensive than today's remnant, spread across the Champlain Basin. Then, as the ice sheet retreated further into Canada, the rising ocean spilled through the St. Lawrence Valley and southward into the basin of Lake Vermont. Turning brackish, the latter became the Champlain Sea, an arm of the North Atlantic, and, for a thousand years or more, harbored a wide variety of marine life; fossils of these sea creatures are found across the basin today.

Finally, as New England rebounded from the weight of the glacier, the Sea slowly drained back toward the Gulf of St. Lawrence and freshwater reclaimed the basin, giving rise to Lake Champlain. Sustained by snowmelt and rainwater from the flanking mountains, the Lake drains northward via the Richelieu and St. Lawrence Rivers, flowing through a glacial valley that once admitted the sea.

Thursday, September 24, 2009

Columbia River Country

On our recent trip to Oregon, we spent some time along the Columbia River, the grand waterway of the Pacific Northwest. Rising in southeast British Columbia, it makes a curve to the north and then heads south, picking up flow from the Kootenay and Pend Oreille Rivers before entering the U.S. In eastern Washington, it is joined by the Spokane, Snake and Yakima Rivers and then heads westward along the Oregon border, taking in flow from the John Day, Deschutes, Williamette, Lewis and Cowlitz Rivers before entering the Pacific west of Astoria. Completing a journey of 1245 miles and collecting flow from a watershed of 258,000 square miles, the Columbia is the fourth largest river in the country and the largest west of the Continental Divide.

The current course of the Columbia has been molded since the rise of the Rocky Mountains, 65 million years ago. Once inundated by shallow seas, the region has experienced periodic volcanism over the past 40 million years and Pleistocene floods eroded the landscape 12-20 thousand years ago; the latter carved the famous Channeled Scablands of eastern Washington. Today, erosion continues, fed by heavy snows across the Rockies and Cascades, and, as many of us witnessed in 1980, regional volcanism continues to sculpt this rugged terrain.

Though beautiful and powerful, the Columbia has been used and abused by those who have settled across its vast watershed. Fourteen dams disrupt its flow, providing hydroelectric power, flood control and water for consumption and irrigation; however, these same structures have had a significant impact on the welfare of salmon populations, a threat only partially mitigated by the construction of "fish ladders." In addition, channelization of the river has augmented industrial development throughout its valley, offering a vital route of transportation; of course, this has resulted in significant water pollution, including material from nuclear plants. As is common across the globe, any attempt to balance conservation and resource exploitation tends to tip against the natural environment.

Tuesday, September 22, 2009

A Perfect Deluge

After enduring more than a year of severe drought, the residents of northern Georgia and bordering States had been hoping for a tropical storm that might restore the vegetation, recharge the streams and fill their reservoirs. Alas, in the middle of a lackluster hurricane season, relief came not in the form of a powerful storm but as the effects of a plodding cold front. Unfortunately, it was a gift that kept on giving, drenching the region with 10-20 inches of rain and producing catastrophic floods throughout the area.

The cold front, curving from the eastern Great Lakes to central Texas, established a clash zone, with warm, humid air to its southeast and cool, dry air to its northwest. As the front inched to the east, a southerly flow of Gulf air invaded the Southeastern States, priming the region for thunderstorms. The front and its low pressure center provided lift, pulling the soupy air up and over the invading wedge of cool air; the terrain of northern Georgia and its border areas, higher than the Gulf Plain to the south and east, augmented this lift as the warm, moist air streamed up from the south. All of these factors ignited thunderstorms along the edge of the front, which, lacking a potent shove from the jet stream, lounged over these uplands, dropping heavy rain before redeveloping and training over the same areas.

In effect, a Perfect Deluge was established and continued to intensify until the front moved further to the east. Despite a respite today, more precipitation is expected throughout the week as another cold front drops from the Midwest. Hopefully, that rainmaker won't linger over this flood zone which has no capacity to absorb additional moisture; any rain that falls will quickly move to the swollen streams and rivers.