Wednesday, December 31, 2008

Celebrity Worship

Throughout human history, our species has been enamored with celebrities. Initially, these individuals were shamans and tribal chiefs, replaced by kings, queens, princes, warriors and priests as time moved on. Though titles and identities have changed, man confers celebrity for a few primary traits: power, physical prowess, wealth and beauty.

Today, in modern Western society, our celebrities are primarily athletes and entertainers and our image of them is somewhat schizophrenic. On the one hand, we expect them to be more than they are; interested in every aspect of their lives, we support the industries that fawn over them, wear jerseys emblazoned with their names and pay ridiculous fees just to be in their presence. Convinced of their importance, we readily overlook their foibles (multiple divorces, drug use, criminal behavior), which often only enhance their celebrity. On the other hand, our sadistic side feeds the gossip mills and the cable shows that focus on their dysfunctional lives; as individuals, they are afforded little privacy.

Man's tendency to worship celebrity is a reflection of the human condition. Well aware of our own flaws and limitations, we are reassured that others have conquered them. And while admiring the talent and achievements of these celebrities, we are also comforted by their failures. In the end, they boost our own self esteem.

Tuesday, December 30, 2008

Winter Marsh

Our Midwest wetlands are surely not as fascinating during the winter as they are during the warmer months. The colorful songbirds have departed for southern climes and wetland wildflowers have long gone to seed. No frogs croak from the shallows and no turtles lounge in the mid day sun. Rails have left their backwater haunts and most waders have moved on to milder wintering grounds. Perhaps most striking is the silence, broken only by the distant call of geese or the friction of dried cattails in the cold winter wind.

But there is still much to see in the winter marsh. A variety of sparrows gather in the dense, dead vegetation, escaping the wind and searching for seeds; song and white-throated sparrows are most common but American tree, fox, Harris' and swamp sparrows may also be found. Northern harriers and sharp-shinned hawks swoop across the marsh, red-tailed hawks circle overhead and barred owls survey the scene from nearby woodlands. If open water persists, wintering ducks (mallards, gadwall, green-winged teal) may be seen and great blue herons, seemingly out of place in the cold, snowy weather, often stalk the shallows.

Those who visit early or late in the day have the chance to observe marshland mammals, most of which remain active through the year. Mink hunt along the banks or man-made dikes, searching for mice, muskrats and unwary ducks. Raccoons and opossums, opportunistic as they are, scour the marsh for anything edible while beaver and muskrat ply the open waters. The colors and noise may have faded but there's still plenty of activity in these crucibles of life.

Monday, December 29, 2008

The Rise of Endotherms

Life evolved in the ocean, some 3.6 billion years ago, and, for most of its history on Earth, has been confined to the sea. Shelled marine life had evolved by 600 million years ago (MYA) and both sharks and bony fish appeared during the Devonian Period, some 375 MYA. The first land animals, millipede-like organisms, crawled ashore during the Silurian (420 MYA), giving rise to terrestrial insects and spiders over the next 100 million years. Amphibians diversified and reptiles evolved during the Carboniferous Period (350-270 MYA) and, by the Permian (270-225 MYA), mammal-like reptiles appeared.

All of the above animals are/were ectotherms: they have an internal body temperature that matches their surroundings (some sharks, fish and insects, able to generate heat in certain muscle groups, are better classified as heterotherms). Early in the Mesozoic (200 MYA), endotherms, initially represented by small dinosaurs and the earliest mammals, evolved; these Triassic creatures (joined by the first birds during the Jurassic) were able to regulate their internal temperature by controlling regional blood flow (to conserve or dissipate heat), by shivering, sweating (or panting) and by maintaining a high metabolic rate. The evolution of fur, feathers and subdermal fat provided additional insulation and improved heat conservation.

Endotherms, most of which are homeotherms (maintaining a stable core temperature), are less restricted by their environment, have colonized all regions of the globe and can remain active during all seasons. Man, of course, has little external insulation but had the intelligence to develop clothing, control fire and build shelters. Mammal hibernation adds a final twist to the story; more than a behavior to escape the cold, torpor is an active process, lowering the metabolic rate, producing hypothermia and conserving energy during periods of reduced food supply.

Sunday, December 28, 2008

Palo Dura Canyon

The High Plains of North America are coated primarily by erosional debris from the Rocky Mountains and by windblown deposits from western volcanoes. The entire province was tilted upward during the late Tertiary Period (the Miocene-Pliocene uplift) and mountain erosion increased during the Pleistocene, when glaciers and meltwater streams enhanced the process.

The eastern edge of the High Plains blends with the lower, Central Plains across much of the Continent but, in northwest Texas, the edge stands out as a prominent escarpment, incised by a series of canyons. The largest of these is Palo Dura Canyon, southeast of Amarillo. Averaging six miles in width and 800 feet in depth, it has been called the Grand Canyon of Texas and is surely one of the more scenic locations in the State. The Ogallala Formation (late Tertiary sandstone and conglomerate) forms the Caprock of the Canyon, which has a surface elevation near 3600 feet; Triassic rocks comprise upper layers of the Canyon, overlying Permian strata, which harbor seams of white gypsum. These Permian rocks represent the upper layer of the Permian Basin, which extends southwestward, where it is covered by younger Mesozoic and Tertiary sediments.

Protected as a Texas State Park since 1934, Palo Dura Canyon was eroded over the last million years by the Prairie Dog Fork of the Red River. It's name, which means "hardwood" in Spanish, refers to the plentiful mesquite and juniper trees that cover the canyon slopes; cottonwoods and willows, less drought tolerant, cluster along the River on the canyon floor. A variety of shortgrass species, yucca, prickly pear cactus and western wildflowers also adorn the Park. Resident wildlife include deer, coyotes, wild turkey, scaled quail, roadrunners and western diamondback rattlesnakes; among the many raptors are golden eagles, prairie falcons and ferruginous hawks. The Park, 12 miles east of Canyon, Texas, is reached via State Route 217; an 8 mile road and numerous trails provide access to this scenic refuge.

Saturday, December 27, 2008

Weather and Wildlife

Today provided inspiration for indoor activities. Heavy rain, falling temperatures and the promise of ice have kept most of us out of the elements. And, equipped with heated homes, cars, malls, theaters and supermarkets, there was little need to venture into the great outdoors. But our wild neighbors, who fend for themselves, have little choice; they must endure the cold rain or skip dinner!

Of course, their fur and feathers provide ample protection as they hunt for prey or scour the landscape for nuts, berries and hibernating insects. In the midst of this morning's downpour, a pair of titmice moved between the feeder and suet block, their distinctive crests plastered to their skulls. At the same time, a fox squirrel, using his tail as an umbrella, managed to dislodge a pine cone feeder before carting it off to his den. And throughout the day, despite the weather, the usual mix of residential birds paid their respects.

Beyond their natural protection and survival skills, wild creatures are not burdened by man's preoccupation with the past and the future. They do not dwell on the glorious days of autumn or anticipate the coming spring. They have no thermometers or calendars to check and are not inclined toward procrastination. Rather, they are focused on the present and must take what comes; their survival depends on a day to day approach to life. If only we could adopt that attitude!

December Deluge

In advance of the latest cold front, strong southerly winds brought warm, humid air into the Heartland over the past 24 hours; at dawn, it was 68 degrees F in central Missouri (five degrees warmer than it was in Tampa, Florida). But, by mid morning, distant thunder warned of a coming change.

The line of thunderstorms arrived at 9:30 AM, accompanied by torrential rain and gusty winds; a doppler-indicated tornado, northeast of Columbia, triggered the warning sirens, which blared across the city for ten minutes or so. The downpour has diminished over the past hour but a second round of storms, attached to the cold front, is now approaching from the northwest and more heavy rain is expected. Since the ground remains frozen from our recent Arctic weather, runoff will be significant and a flash flood watch has been issued for most of the region.

Behind the front, temperatures will fall through the day, bringing a mix of sleet and snow by this evening; the overnight low is forecast to be in the mid 20s. After a brief taste of spring, more seasonable conditions should prevail throughout the coming week.

Friday, December 26, 2008

Barrier Islands

Barrier islands, among the most transient landforms on the planet, are common along the Atlantic and Gulf Coasts of North America, from Cape Cod southward. Formed by the action of waves and currents, these narrow islands are essentially offshore dunes, stabilized by a variety of grasses, shrubs and trees; this natural vegetation, tolerant of the salty and sandy conditions, is derived from seeds that blow out from the mainland (man has since added his own assortment of ornamental species).

Initially inhabited only by sea birds, marine mollusks and temporary visitors (such as sea turtles), most of the islands now harbor beach resorts, perched precariously on these shifting mounds of sand. While modern structures are anchored into the deep bedrock, all development on the offshore islands is prone to damage or destruction from the tropical storms and hurricanes that sweep across the region. In addition, island wildlife is threatened by mainland species (such as raccoons) that now reach these sandy refuges via man-made bridges.

Barrier islands form along coasts were the Continental Shelf is broad and shallow, making them especially susceptible to storm surge and wave erosion. Islands not destroyed or cut apart by storms will eventually merge with the mainland as the intervening bay is filled in by river sediment and by sand pushed through the inlets. Of course, humans keep their boat channels open by dredging, but, in time, nature will have her way!

Wednesday, December 24, 2008

Man and his Gods

Throughout human history, which spans 125,000 years, man has imagined gods and mystical beings that would supply his needs (rain, a good harvest, wealth) and protect him from danger (storms, warfare, illness, death). Over time, the identity of these deities has evolved but their purpose remains the same. Today, our preferred image is determined by our culture and, as in the past, is ingrained in our psyche during childhood.

One would like to think that such beliefs are harmless social customs that promote the common good. But anyone with a knowledge of history understands the dark side of religious fervor; too often, it is a source of hate, discrimination, intolerance and persecution.

Tomorrow, Christians celebrate the birth of Jesus, who, they believe, was the Son of God. By all accounts, he led a simple life, preached tolerance and encouraged his followers to share their talents and wealth. Two thousand years later, the Christian Church has become a political and financial power broker, run by entrenched hierarchies and media entrepreneurs. Conservative Christian zealots, self-righteous and narrow-minded, foster intolerance and work to impose their social agenda. Unfortunately, there are plenty of fearful, uneducated, guilt-ridden followers to heed their call, marking the latest chapter in man's quest for immortality.

Merry Christmas to all!

Tuesday, December 23, 2008

The Misnamed Woodpecker

Most abundant in pine lands and bottom woods of the Southeast, the red-bellied woodpecker is common in open woodlands and residential areas of eastern North America, from southernmost Canada to Florida; those that breed across northern limits of this range move southward in the winter. Feeding on a wide variety of insects, nuts and berries, the red-belly often visits backyard feeders, especially during the colder months, and it is then that novice or casual birders first notice it.

A bit smaller than the similarly shaped flicker, this woodpecker is identified by his black and white "ladder back", beige underparts and bright red crown (limited to the nape in females); ironically, it is named for a pale red blush on its abdomen which is often invisible in the field. A distinctive, rolling "churrr" usually announces its presence; unlike flickers, the red-bellied woodpecker is seldom found in flocks.

Perhaps this species should have been called the zebraback or red-crowned woodpecker but the power brokers of the bird world make these decisions. Regardless of its name, the red-belly, attractive and beneficial, is always a welcome visitor in our yard!

Monday, December 22, 2008

Out of the Dark

Having just endured the longest night of the year, our daylight will gradually lengthen until the summer solstice, on or about June 21; this reflects the tilt of the Earth's axis, causing the Northern Hemisphere to receive increasingly direct solar radiation through the period. Of course, the sun angle will remain too low to provide significant warmth at our latitude for another two months and there will be plenty more winter weather before spring takes hold.

Even so, it is reassuring to know that the days will be lengthening. Humans are not naturally equipped for the cold and the dark. We evolved in the Tropics and, regardless of our personal preferences, we have a deep-seated connection to warm, sunny weather. Besides, with the exception of deep ocean ecosystems, all life on Earth is dependent on the sun. Primitive man, though devoid of scientific tools, knew this instinctively and marked the solstice with various rituals. Today, we understand the astronomical cause for the event but it is no less comforting.

Sunday, December 21, 2008

The Gangplank

As the Mesozoic Era ended, 65 million years ago, the dinosaurs were dying out and the Rocky Mountains were crumpling skyward. In concert with their rise, the forces of erosion began to work on these highlands and aprons of debris, carried by wind and water, spread out from their flanks. Throughout much of the Tertiary Period, the mountain summits barely poked above these vast plains of debris.

Then, in the Miocene Epoch (some 20 million years ago) a second, more general uplift of the Mountain West began, adding 5000 feet to elevations across the Colorado Plateau and Rocky Mountain Province. This uplift, which continued into the Pliocene, accelerated stream erosion throughout the region; the process was further enhanced by the cold, wet climate of the Pleistocene, as mountain glaciers carved deep canyons and massive amounts of meltwater carried away much of the erosional debris that had enveloped the mountains.

When early explorers and settlers reached western North America, the Front Range of the Rockies imposed a formidable barrier from Canada to New Mexico. Though steep, narrow passes were adequate for travel by foot or horseback, the search for a train route uncovered an area in southern Wyoming where Tertiary sediments had survived the elements of erosion. Known to geologists as The Gangplank, this wide, natural pass west of Cheyenne offers a gradual climb between the watersheds of the North and South Platte Rivers; the Union Pacific line and Interstate 80 use this route today, crossing the Laramie Range between the High Plains and the Laramie Basin.

Saturday, December 20, 2008

Bird Count

More than most people, I enjoy solitude, especially when visiting wild areas. The sights, sounds and smells of nature are, in my opinion, best appreciated in the absence of human conversation. But twice each year, near Christmas and in the spring, I take part in the annual Audubon birding counts, established to monitor the status of regional bird populations.

Our group is assigned to rolling farmlands south of Columbia, between the Missouri River, on the west, and U.S. 63. We gathered just before dawn and set out to survey are region, winding along country roads and stopping at selected sites to look for birds. It was a cold, gray day but the birding was decent and most expected species were found; as usual, juncos, crows, robins, blue jays, cardinals, flickers and starlings were among the more common. We also saw red-tailed and red-shouldered hawks, a lone bald eagle, a variety of woodpeckers, yellow-rumped warblers, purple finches, swamp sparrows and northern mockingbirds; during our six hour excursion, forty species were tallied.

The highlight of today's count was the large number of cedar waxings. In most years, we see several flocks of these attractive birds, generally yielding a total of fifty or so. Today, we saw hundreds of waxwings; in fact, it was the most numerous bird on the list, even surpassing our tallies for juncos and starlings. Though the reason is uncertain, it is likely that these nomadic birds abandoned more northern parts of their range after recent heavy snows across that region.

Friday, December 19, 2008

The Tahoe Basin

Though the Sierra Batholith formed back in the Mesozoic Era, this massive pluton of rock did not rise to create the Sierra-Nevada Range until the late Tertiary Period, about 3-4 million years ago. As it rose, the forces of erosion began to sculpt its summits and fault lines developed along its margins. Along the northeast edge of the batholith, a block of crust (known as a graben) dropped between parallel faults, with the Sierra rising to its west and the Carson Range uplifted to its east; the resulting basin is now known as Tahoe.

Streams from the surrounding highlands gradually filled the basin, the margin of which was continually molded by uplift, faulting, landslides, volcanic debris and glacial erosion; the latter was especially significant during the Pleistocene Epoch as glacial valleys formed along the west edge of the basin, glacial moraines altered drainage patterns and glacial meltwater added significant depth to the basin's lake. As one might expect, the surface level of Lake Tahoe, which now sits at 6225 feet, rose and fell significantly over the past 2 million years.

Today, the Truckee River is the only outlet from Lake Tahoe, flowing northeastward into the Great Basin, where it feeds Pyramid Lake. Lake Tahoe itself, with a maximum depth of 1645 feet and a surface area of 191 square miles, is the largest alpine lake in North America and the third deepest lake on the Continent (behind Great Slave Lake and Crater Lake). Known for its scenic setting and for the clarity of its water, Lake Tahoe sits above two fault lines, making the area prone to earthquakes and a potential tsunami; like all lakes, mountains, plains and canyons, it is a beautiful but temporary feature of our planet's landscape!

Center of the Storm

This week's powerful winter storm, on its way from Southern California to New England, passed just north of Columbia through the night. As it approached, energized by the jet stream, a thunderstorm erupted above the city, a startling event after days of frigid weather. Strong, counterclockwise winds, surrounding the central low pressure, brought in warm air from the south and, at dawn, it is 42 degrees F; winds are from the southwest, gusting to 40 mph.

As the storm continues its journey to the northeast, its trailing cold front will sweep across Missouri, the winds will shift to the west-northwest and the temperature will fall through the day. We can expect relatively mild conditions over the next 36 hours before another Arctic air mass plunges into the Heartland. Just another winter in the Midwest!

Thursday, December 18, 2008

Transcontinental Express

Developing at the base of a deep, western trough, the latest winter storm brought heavy snows to the Southern California Mountains, southern Nevada desert and Mogollon Rim yesterday. This morning, the storm is moving toward the Four Corners, spreading snow across the Colorado Plateau and Southern Rockies.

By this afternoon, the storm will hitch a ride on the jet stream and move across the Central Plains. Rain, sleet and freezing rain will develop along its path (Kansas-Missouri-Illinois) and heavy snow is forecast for the Upper Midwest. Moving on through the night, this weather system will be in New England by tomorrow morning, ensuring a White Christmas for much of that region.

Of course, most North American storm systems move from west to east, governed by the prevailing winds. The speed of their movement is generally related to their proximity to the jet stream and this one is taking the Transcontinental Express!

Wednesday, December 17, 2008

Owl Nights

We are now facing the long, cold nights of winter, the season of the owl. Equipped with superb vision and hearing and insulated with a dense coat of feathers, the owls rule these frigid nights, oblivious to the conditions. Their prey, primarily mice, voles and cottontails, must stay active to survive and the patient owls are waiting.

This is, in fact, the onset of the breeding season for great horned owls and their hoots will build over the next six weeks. We humans, not naturally designed for this season, retreat to our heated dens; a night in the cold and snow is but a bad dream. But we take solace in the call of the owl, a message that nature's cycle endures and that, in time, spring will arrive.

Monday, December 15, 2008

A Taste of the Arctic

Those of us who live in the Temperate and Tropical Zones cannot truly appreciate the conditions faced by humans and other animals that inhabit the polar regions. This latest Arctic outbreak, triggered by a broad dip in the jet stream, is giving us a taste of life at the Poles. Extreme cold has invaded the Northern Plains, where morning lows hovered at 20-30 degrees F below zero; add in the wind effect and we're talking serious cold!

The development of extreme cold requires a lack of solar heating and limited cloud cover; the latter permits heat to radiate into space and is a common feature of the dry polar climate. In the Arctic, a perpetual night began in mid November and will last until late January; the only warming that they will experience is via southerly winds ahead of polar fronts. In a twist of fate, their relief is at our expense as the intense, Arctic cold is displaced to the south; on the positive side, this polar air is extremely dry and precipitation, in the form of rain, snow or ice, is generally short-lived, moving off with the frontal boundary as the cold, dense air rushes to the south and east.

Looking out from my office window this morning, I watched a snowball moon set behind a flat shelf of snow-white clouds. The temperature was 6 degrees F.

Sunday, December 14, 2008

Windblown Ducks

It was a gray, mild, windy afternoon at Eagle Bluffs yesterday, as a strong southerly flow developed in advance of the next cold front. As usual, there was a large number of wintering ducks at this Missouri floodplain conservation area, southwest of Columbia. Mallards, pintails, gadwalls and green-winged teal were well represented and ring-necked ducks were especially abundant. On the other hand, only a small number of Canada geese were seen and no snows graced the refuge.

The highlight of this visit was the aerial spectacle of the numerous ducks as they attempted to move among the lakes, ponds and sloughs, challenged by the strong southerly winds. Those flying with the wind zoomed effortlessly across the landscape while other flocks, heading against the gale, were blown about, forcing them to veer off course or drop to the surface and wait for the wind to diminish. Many, especially the flight-challenged coots, huddled along the leeward edge of cattails while diving ducks, comfortable in the choppy water, formed rafts on the larger lakes.

To one who looked out across the refuge, the restless ducks, moving in small groups or large flocks, at various angles to the persistent wind, had the appearance of windblown leaves, scattered through the winter sky. Even they, equipped with lean, muscular bodies and instinctual flight skills, were at the mercy of nature's power.

Saturday, December 13, 2008

New England Orogenies

New England has a complex geologic history and, like much of the western U.S., was pieced together by a series of exotic terrains. At the beginning of the Ordovician Period, the east coast of the region was west of what is now the Hudson Valley; then, about 450 million years ago (MYA), an elongated island chain collided with the Northeast coast, adding much of western New England and a large portion of the Canadian Maritime Provinces. This collision initiated the Taconic Orogeny, uplifting a range of mountains from northeast Canada to present-day Virginia.

Fifty million years later, the Avalon Subcontinent, which sat in the northern Iaepetus Ocean, between the North American and European Continents, slammed into New England, adding coastal New England, Nova Scotia and the Avalon Peninsula of Newfoundland; its northeast segment would become northern France and the British Isles. The collision of Avalon with North America triggered the Acadian Orogeny, raising mountains where the Northern Appalachians now stand.

By the end of the Devonian Period, some 350 MYA, these ancestral ranges had nearly eroded to the surface but a new, more extensive Orogeny would soon take place. Throughout the Carboniferous Period, the age of extensive fern forests, giant amphibians and primitive reptiles, the Iaepetus Ocean continued to close, drawing Africa and North America together. The eventual collision of these Continents (320-250 MYA) would produce the Appalachian Orogeny, lifting a continuous chain of mountains from eastern Canada to eastern Oklahoma; these are now known as the Appalachian Mountains (from New England to Alabama) and the Ouachitas (west of the Mississippi Valley). Initially resembling the modern Rockies and Alps, these older mountains have since eroded into lower summits which, except in northern New England, are rounded off and covered by forest.

Thursday, December 11, 2008

Bayou Snow and Northeast Ice

The latest polar plunge, triggered by a dip in the jet stream, was deeper than initially forecast, allowing frigid air to reach the Gulf Coast. At the same time, this advance was rapid and broad, shoving the southern storm eastward rather than northeastward.

Sitting over Mississippi this morning, the powerful storm is raking the Southeast with heavy rains and its "wrap-around" moisture, forced to rise above the entrenched cold, is producing light snow across east Texas and much of Louisiana. The east edge of the polar trough now stretches along the Appalachians and, as the storm moves up the Atlantic Coast, inland snows and coastal rains will be separated by a swath of ice.

Once again, the exact location and extent of the ice storm is difficult to predict but current forecasts suggest crippling conditions will develop from northern Virginia to southern New England. Meteorology is certainly one of the most interesting and frustrating fields of natural science!

Tuesday, December 9, 2008

Dueling Rams

Rocky Mountain bighorn sheep, one of four wild sheep species in western North America, inhabit the Central and Southern Rockies, from Alberta to New Mexico. Grazers, they feed on grasses and forbs, favoring steep, sunny slopes; ewes and their young tend to remain at lower elevations of the foothills and mountains while bachelor herds may be found above timberline during the summer months.

Their annual rut, featuring head-on collisions of the 400-pound rams, peaks in December and is best witnessed in foothill canyons, below 9000 feet. These duels determine breeding rights and, after this seasonal frenzy, all spend the winter in peaceful coexistence. Impregnated females give birth to a single lamb (twins are rare) in late May or June, by which time the rambunctious males have moved to higher ground. The lifespan of the Rocky Mountain bighorn averages 10-12 years but their gregarious lifestyle makes them susceptible to outbreaks of parasitic disease, especially lungworm pneumonia; others die from falls or from predation by humans, mountain lions or coyotes.

There are many places to observe the bighorn rut throughout Colorado; some of the more reliable locations along the Front Range include Waterton Canyon (southwest of Denver), Mueller State Park (west of Colorado Springs), along I-70 (across from Georgetown) and Big Thompson Canyon (U.S.34, west of Loveland). Regardless of where you go, bring warm, layered clothing and binoculars; be aware that dogs are not permitted in Waterton Canyon.

Monday, December 8, 2008

Southern Storm

A storm has developed over the Southern Plains, just ahead of the next polar plunge. As the cold front pushes to the east-southeast, this storm will move northeastward, pulling in plenty of moisture from the Gulf of Mexico.

Rain will develop ahead of the front while heavy snow is forecast for the Upper Midwest. The exact position of the rain-snow line will depend upon the relative positions of the storm and the front; such uncertainty is a challenge and a potential source of embarrassment for meteorologists. Here in Missouri, we are beginning to feel the southerly flow this morning, with a dawn temperature near 40 degrees F; we should remain on the warm side of the system for the brunt of the storm and significant rainfall is forecast for tonight and tomorrow.

The primary benefit of this storm will likely be seen across the Southeast, where a few days of rain should bring some relief from the prolonged drought. Those on the snowy side of the front may not share their appreciation!

Sunday, December 7, 2008

Sunday Driver

When I was a boy, my father used to get angry with "Sunday drivers," those people who drove along in a leisurely fashion, taking in the sights. Now, in middle age, I am one of them.

Today's drive took me southwest of Columbia, looping among farms, across the Missouri River floodplain and past the outer sprawl of this college town. The bright sky, cold and blue, was in stark contrast to the faded greens and browns of the early winter landscape. The usual mix of rural birds, dominated by red-tailed hawks, American kestrels and mourning doves, perched along the roadways and placid farm animals, well fed and content, reflected the serenity of country life. Hoping to spot a flock of snow geese heading south, I saw only an occasional group of Canadas, honking their way above the farmlands.

In truth, it's not easy to take a leisurely drive through the country anymore; drop below forty and you'll soon have a pickup on your bumper. Humans continue to fill the open spaces and the pace of life has increased in concert. The Sunday driver is a threatened species!

Saturday, December 6, 2008

California's Great Valley

Looking at a map of the U.S., one might think that California's Central Valley, on the west coast, and the Chesapeake Bay, on the east, were formed in a similar way; but they would be wrong. While the Chesapeake represents a drowned river valley, the Great Valley of the Golden State is far more complex.

When the Atlantic Ocean began to open, during the Jurassic Period, the west coast of the North American Plate was forced to collide with the Farallon Plate, which underlied what is now the eastern Pacific Ocean; at that time, the west coast of North America was at the longitude of central Utah. As pressure mounted, the Farallon Plate was forced to subduct beneath North America and, as the latter moved westward, a series of exotic terrains and volcanic island arcs were added to the Continent. Between these land masses, seaways were forced to close and, in the process, their oceanic crust was either subducted beneath the growing continent or forced to crumple onto its edge.

The area now covered by California's Great Valley was once one of these entrapped seaways. In fact, it was a deep subduction canyon; to its east, the Farallon plate was melting into the massive batholith of the Sierra Nevada. Over time, this seaway became surrounded by mountainous terrain as the Cascades, Sierra, Coastal Range and Transverse Range formed; sea deposits, volcanic debris and erosional sediments from these highlands gradually filled the sea basin and the surface of the inland sea rose and fell in concert with changes in the Earth's climate. Its connection with the Pacific, once at the latitude of Monterey, shifted northward as the Farallon subduction ended and land shifts along the San Andreas Fault began to reshape the coast.

Eventually filled to the brim with sediments, the massive estuary shrunk to its famous remnant: San Francisco Bay. Throughout the Pleistocene, extensive meltwater lakes covered most of the Valley but, today, reservoirs and water diversion have cut off most of that flow, threatening the health of the Bay and its adjacent wetlands. The Valley itself, once a seaway, has become a flat landscape of desert, irrigated croplands and cities; beneath its surface are miles of sediment.

Friday, December 5, 2008

The Winter Hawk

Having bred and summered across northern Canada and Alaska, rough-legged hawks drift southward through autumn and winter in the U.S.; since they favor open country, these large buteos are best observed across the Great Plains and Intermountain West.

Heavy bodied and long-winged, rough-legged hawks are identified by their appearance and their behavior. Field marks include a light-colored head, dark patches at the bend of each wing and a white tail with a black terminal band; their name reflects prominent feathering of their legs and feet. Despite their size, these raptors often hunt by hovering over their prey and are known for their habit of perching precariously on thin snags or limbs.

Rough-legs feed primarily on lemmings, mice and voles but may feast on the remains of deer or pronghorns that succumb to the winter snows. Come spring, they return to their Arctic and Subarctic haunts where they nest on cliffs or rocky outcrops.

Thursday, December 4, 2008

Colds and the Cold

As the first major blast of winter envelops much of the country, children and adults will be cautioned to avoid "catching cold." After all, the flu and common cold are widespread at this time of year and many assume that cold weather is responsible.

In a way, it is responsible, keeping more people indoors and close together. All of our common viruses are acquired from other persons, either through intimate contact or via droplets spread by sneezing and coughing. The more interaction we have with others, the more likely we are to become infected.

But while prolonged exposure without proper clothing can be harmful (or even fatal), there is little evidence that cold air, itself, increases our risk for infections. Rather, if properly attired, outdoor exercise is just as beneficial in winter as it is during any other season. And beyond its aerobic and stress-reducing benefits, the winter walk takes you away from the viral reservoirs in our homes, offices and shopping malls!

Tuesday, December 2, 2008

The Eastern Quail

Represented by more than 20 subspecies, the northern bobwhite inhabits central and eastern North America, from southern Canada to Mexico; introduced populations are also found in the Pacific Northwest. Despite their broad range, these small quail are subject to periodic die-offs related to severe cold or heavy snow and are threatened by habitat loss in many areas.

Northern bobwhites favor brushlands and immature woodlands where they forage for insects, seeds and berries. Once maintained by occasional wildfires, drought and storms, such habitat has been replaced by suburban sprawl, crop fields, tree farms and mature forest across much of the quail's range. Bobwhites pair off intermittently throughout the spring and summer, raising several broods each year; however, this high reproductive rate is balanced by loss due to weather or predation (fox, weasels, accipiters, owls) and most chicks die within a year. By October, survivors gather in coveys of 20-30 birds, moving and feeding as a group before huddling together on cold winter nights.

As I learned during my boyhood in southern Ohio, bobwhites are more often heard than seen throughout the warmer months, when the distinctive call of the male echoes across fields and farmlands. During the fall and winter, these quail are usually encountered when hikers or dogs spook a covey, causing the members to explode from the brush in all directions.

Monday, December 1, 2008

Winter Arrives

While the winter solstice is still three weeks away, the calendar has flipped to December and the last 24 hours have provided the first real taste of winter. Though periods of cold weather were spaced through the autumn and warm interludes are sure to follow, the cold, darkness, wind and snow of this past day surely marked a transition.

Cold temperatures, day and night, will now rule until March, when the sun begins to reclaim its territory. In the meantime, darkness and quiet will prevail, a survival mode will be adopted and hunters will rule the landscape. And, of course, many humans will retreat to the great indoors and dream of spring.

But those of us who relish the stark beauty of winter will take to the deserted trails and enjoy the quiet solitude of this maligned season. There we will find that our wild neighbors, undaunted by the cold, have no interest in the calendar. For them, retreat is not an option.