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Showing posts from July, 2011

Driving back through Time

Leaving Denver this morning, I headed east across the High Plains of eastern Colorado which have a veneer of late Tertiary sediments (about 5-30 million years old), eroded from the Rockies or blown eastward from volcanoes of the Western U.S. Now sculpted into broad uplands and valleys across the Colorado Piedmont, these deposits form loosely compacted strata that overly Cretaceous shale and sandstone; the latter sediments, some 100 million years old, are upturned as a hogback along the base of the Front Range and are exposed across the "lowlands" of the South Platte Valley.

By the time I reached central Kansas, the relatively young Tertiary sediments had disappeared and Cretaceous limestones lay just beneath the soil; these chalks and "post-rocks" were deposited in a broad, shallow sea, which stretched from the Texas coast to northwest Canada about 100 million years ago (MYA). Just east of Junction City, I-70 climbs into the Flint Hills, composed of Permian strata…

The Nature of Landscape

To most people, landscape is merely the physical geography of a region, whether it be mountainous terrain, forest, grassland, desert, seascape, etc. But to those of us who are enamored with natural history, landscape is the present-day product of underlying geology, plate tectonics, erosive forces, climate and human engineering which have determined its landforms, soil condition, hydrology and vegetation patterns. Furthermore, any given landscape is composed of various habitats and micro-habitats, harboring a diversity of life that is not always evident to the casual observer.

Naturalists, interested in the varied geophysical and biologic components of landscapes, tend to be fans of topographic maps, aerial photography, satellite imaging and other tools that lend perspective to any given region on Earth. Understanding the interplay of the many factors, past and present, that mold the continents and drive evolution, we know that landscapes offer clues to both the past and future his…

The Nature of Education

During this era of budget cuts, rising tuition and widespread unemployment, there is increasing discussion regarding the necessity of a college education. Despite the fact that one's eventual income and financial security is directly tied to his or her education level, opting for a trade school is a reasonable choice for many individuals and may lead to a lucrative and fulfilling career. But, unless these individuals make the effort to broaden their personal education, this choice comes with a price, both for the individual and for human society.

A college education encourages us to open our minds to other disciplines, other cultures and, most importantly, other points of view. Indeed, it is common for college students to change their major in the course of their studies, often in response to a field of study with which they had no previous experience. Even if the student sticks with their initial major, a choice made at the ripe old age of 18, he or she is exposed to a variet…

Washington's Eocene Coast

During the Eocene Period, some 50 million years ago, sediments collected across what is now western Washington. The majority of these deposits were continental in origin, eroded from pre-Cascade uplands to the east; some, especially across southwestern Washington, were marine in origin, deposited in shallow seas as ancestral whales were first returning to the ocean.

Today, these Eocene sediments underlie Puget Sound and the urban areas that hug its shoreline. Continental Eocene deposits, both sedimentary and igneous, also comprise the Olympic Mountains and a mix of marine and terrestrial Eocene sediments have been folded to create the Coastal Range, further south; nearing the Oregon border, younger Miocene deposits also appear in this latter Range.

The modern Cascades, volcanic in origin, are composed of much younger rock, forming from the Miocene (about 20 million years ago) to the present day. The major stratovolcanoes (Ranier, St. Helens, Adams) rose during the Pleistocene (with…

Vacation Athletes

Many Americans, having spent most of the year overeating and relatively inactive, decide to get in shape on their vacation. We have all seen them, middle aged, obese men or women, jogging along the beach or trudging up mountain slopes. Such sudden, catch-up exercise is both futile and dangerous.

While all efforts to exercise should be commended, conditioning programs should be gradual and sustained, not crammed into a week at your favorite resort. Attempts to stress an unprepared body will risk muscular injury, heat exhaustion or cardiovascular collapse; lifeguards, park rangers and ski patrol members see these self-induced emergencies on a regular basis.

For those who are truly committed to improving their physical health, dietary and exercise regimens must be sustained throughout the year, should begin at a comfortable level and should be undertaken with reasonable expectations. Walking, biking and swimming are the best options for most deconditioned adults and allow a steady in…

Colorado's Beetle Blight

While massive forest fires grab headlines across the globe, the more widespread and insidious destruction of trees by beetle infestation is relatively unknown to the public at large. But foresters, tourism officials, resort owners, utility workers and anyone who drives through the mountains of Colorado are keenly aware of the extensive destruction wrought by the mountain pine beetle.

These beetles are natural residents of pine forests, generally feeding on and reproducing in aging and stressed trees, thereby helping to maintain the health of the ecosystem. However, over the past decade, the population of these voracious insects has exploded, thanks to extensive stands of mature lodgepole pine, partly created by wildfire suppression. Arising in north-central Colorado and spreading southward into the heart of ski-country, the epidemic has turned magnificent green forests into an ugly patchwork of dead and dying trees, broken only by stands of aspen and spruce. Adding fuel to the d…

Grizzlies in Colorado

Before white settlers and trappers reached the American West, grizzly bears were common throughout the western two-thirds of Colorado, from the Front Range to the high mesas of the Colorado Plateau. By the mid 20th Century, wildlife officials assumed that these large predators had been extirpated from the State, shot or trapped into regional extinction by ranchers, hunters and anyone else who felt threatened by their presence; indeed, the "last grizzly in Colorado" succumbed to a trapper in 1952, snared and killed in the San Juan Mountains.

Assumed to no longer inhabit the State, grizzlies were nevertheless placed on Colorado's endangered species list by the Division of Wildlife. Then, in the autumn of 1979, a lone grizzly attacked a hunter near Pagosa Springs and was killed in self defence; surely this had been the sole surviving member of the species in our State. However, scattered sightings have continued, even by persons with significant prior contact with thes…

Riding the Wind

Thanks to birthday gifts from our three children, my wife and I took our first hot-air balloon ride this morning. Launching northeast of Boulder, Colorado, we drifted to the southeast on a light breeze and remained aloft for some 75 minutes, covering twelve miles or so.

Enroute, we enjoyed spectacular views of the Front Range and a unique perspective on the mosaic of reservoirs, ranches, wetlands and suburban developments that cloaks the Colorado Piedmont. We also found that ballooning is an extremely peaceful experience, taking one far from the noise of human activity and nature herself; only the occasional helicopter or airplane disturbed the serenity.

As with other forms of flight, balloon travel yields an appreciation for the topography below, today revealing the contour of stream channels and their associated woodlands, from the foothill canyons to the South Platte Valley. And, from two thousand feet, the world below, while bustling with activity, conveys a message of tranquil…

May in July

Were it not for the high temperatures and the season's first crop of prairie sunflowers, one would think it is May along the Front Range of Colorado. Due to a chilly spring, which delayed melting of the winter snowpack, and to the recent monsoon rains, the South Platte and its tributaries are bank-full and greenery dominates the landscape, usually dull brown by late July.

The monsoon thunderstorms, firing up again this evening, are gifts of the high pressure dome that has brought drought and scorching temperatures to West Texas and the Southern Plains. Moisture from the Gulf of Mexico and the Gulf of California is swept northward between this atmospheric dome, with its clockwise winds, and the seasonal low over southeastern California, which produces a counterclockwise flow. A swath of monsoon thunderstorms, drifting NNE, generally develops by late June in the Desert Southwest and peaks in Colorado by August; needless to say, we are well ahead of schedule this year.

As often oc…

Crossing the Dome

Heading back to our Littleton, Colorado, farm, we left Columbia on another warm, humid morning. West of town, the Missouri River had spilled across its floodplain, but, for the rest of our journey, the landscape would reflect the relentness heat and drought of the past month.

The hazy, humid air persisted through eastern Kansas, where the Flint Hills had faded to an olive green, but gave way to smoky air in central Kansas, where ranchers took advantage of relatively calm winds to burn their fields. In western Kansas and eastern Colorado, the thin air was free of haze but the intense sunshine evened the score and a strong, southerly wind produced a blast furnace effect. Indeed, wildlife was rarely encountered on this hot afternoon and herds of cattle either gathered in the shade of trees or billboards or, better yet, congregated in farm ponds.

These brutal conditions are the product of a massive, high pressure dome which continues to dominate the central U.S., diverting moisture and …

Avian Pizza Party

In mid summer, my early morning walks to work are less interesting than during other seasons of the year. Even before sunrise, the steamy heat has suppressed the local wildlife; birdsong is nearly absent, except for the eternal optimism of chickadees and Carolina wrens, and cottontails lounge in the clover, content to risk my close approach.

But this morning, as I walked along Greek Row, a noisy crowd of starlings and house sparrows had gathered up ahead, squabbling over something in the road. After reaching the scene, I discovered several pieces of pizza scattered across the pavement, no doubt flung from a car overnight. Despite the heat and humidity, these avian opportunists welcomed the bonanza and each aggressively pursued its share.

While most birders despise alien species such as starlings and house sparrows, I tend to admire their survival skills. Omniverous and tenacious, these birds have found nirvana in America, where we throw out more food than most countries consume.

The Nature of Justice

Unlike truth, which is absolute and universal, justice is not found in nature; rather, it is a concept that exists solely in the human mind. For this reason, the definition of justice is influenced by one's culture, religion, philosophy, socioeconomic status and political affiliation and its enforcement is often uneven and arbitrary. To some, justice is merely a synonym for revenge while, for others, it represents the heart of morality.

The concept of justice fuels religious belief, offering hope that the suffering, discrimination and cruelty of this life will be remedied in the next. Indeed, the prospect of an eternal reward encourages self-imposed martyrdom, whether adopted by monks or terrorists. Such mysticism, widespread in human culture, soothes the mind, assuring us that a divine purpose underlies the death of children, the hardships imposed by natural disaster or the sudden calamities of accidents and illness.

Experience teaches us that life is not fair and that justic…

A Dome of Drought

A persistent dome of high pressure has dominated the Southern Plains and lower Mississippi Valley for the past several months, shunting storm systems to the north and exacerbating the severe drought that plagues the region; indeed, its presence deprived Texas of tropical moisture from the season's first Atlantic storm, which was deflected westward across Mexico. Combined with a deep atmospheric trough that covered most of the West throughout the spring and early summer, this dome has also contributed to the flooding across the Central Rockies and Northern Plains as Pacific moisture was swept north and east along its rim.

Over the past two days, this blocking ridge has dropped further to the south, allowing a cold front to ease conditions across the Midwest; here in central Missouri, we should stay in the 80s (F) for the next couple of days before the dome inches northward once again. Meanwhile, to our south, the intense heat and drought continue, with highs above 100 degrees and…

Owls in a Steam Bath

Immersed in another heat wave, it was 82 degrees F at six this morning and the afternoon high is expected to reach 100 degrees. Combined with the high humidity, this heat has enveloped central Missouri in an atmospheric steam bath.

Yet, as I left for work in the predawn haze, two barred owls called from the nearby woods. Unlike their great horned cousins, these owls are often heard throughout the year and, in early spring, frequently call during the daylight hours. Even so, their questioning voices seemed out of place in the soupy air of a Midwest summer.

The owls will retreat to shaded roosts before the morning sun fuels the damp inferno, re-emerging tonight to hunt for mice and cottontails. We admire their hardiness during the frigid months of winter and, trapped in this steam bath, I appreciated their visit this morning; their distinctive calls reassured me that the cool, refreshing days of autumn are on the distant horizon.

The Joy of Flight

Most birds use their natural flight capability to move about, migrate, escape predators and attack prey; but some, at least for part of their day, appear to indulge in the pure joy of flight.

Eagles, vultures and buteos are perhaps the most notable participants, soaring above the landscape for hours at a time with no apparent purpose other than surfing the wind. Others include various gulls, petrels, white pelicans and kites; one might also give a nod to frigatebirds and albatrosses but their physical limitations on land keep them aloft.

Of course, hardcore evolutionary biologists will attribute this nonfuntional activity to the natural instinct to exercise flight muscles but most of us know whimsical behavior when we see it. After all, humans have envied this avian capability throughout our history and have attempted to mimic their aerial freedom with parachutes, gliders and a wide variety of aircraft. Alas, we will never fully experience the joy of flight that our feathered neigh…

The Ground Cuckoo

Natives of Mexico and the Desert Southwest, greater roadrunners have spread eastward and northward over the past Century and now reside in California's Central Valley, across the Southern Plains, in western portions of Louisiana and Arkansas and in the glade country of southwest Missouri. Unlike their North American cousins, the yellow-billed and black-billed cuckoos, which feed primarily on caterpillars and migrate south for the colder months, roadrunners are omniverous and occupy their range throughout the year.

Easily identified by their classic silhouette, shaggy crest, streaked plumage and long tail, these birds have relatively small wings and rarely take flight; rather, equipped with long, powerful legs, they outrun their prey and predators. Food sources include berries, seeds, insects, scorpions, lizards, snakes and small mammals; renowned for their willingness to attack rattlesnakes, roadrunners often cooperate to make a kill. Nests, consisting of sticks and dry grass, …

An Evening Kite Display

Stepping onto our back deck last evening, I caught site of three hawks circling in the distance. Initially assuming they were red-tails, I soon realized that they were smaller, more agile birds. Though they did not manifest the jerky flight of nighthawks, I was leaning toward that identification when one of them suddenly went into a steep dive before careening upward to rejoin the others. Wondering if they might be falcons, I rushed in to grab my binoculars and was able to study their distant forms in more detail; their long, tapered wings were relatively narrow and dark colored, their bodies were light gray and their buteo-like tail was black. Our mystery visitors were, in fact, Mississippi kites.

Recently confined to southern regions of the U.S., these raptors have spread to the north and west, now inhabiting open woodlands and tree-studded wetlands from Iowa to southeast Colorado and from the Desert Southwest to the Gulf Coast. Highly sociable, they often nest in colonies, bui…

The Nature of Haboobs

Haboobs are dense, atmospheric walls of dust or sand that are encountered in arid regions across the globe. Ironically, they usually develop during the monsoon season when downdrafts from nearby thunderstorms produce outflow gust fronts that sweep particulates into the air. Moving out from the central storm, the imposing wall may be a mile or more high and closes in at 30-50 miles per hour, producing a visual doomsday effect.

Though short-lived, haboobs dramatically reduce visibility and, while they may bring destructive winds and induce breathing difficulty, their primary danger results from the rapid loss of visibility, leading to vehicular accidents. Fortunately, they can usually be spotted from a safe distance and modern radar systems provide ample warning of their development, reducing the occurrence of injuries and fatalities.

Yesterday's haboob in Phoenix, Arizona, was spawned by a cluster of thunderstorms northwest of Tucson. According to the Weather Service, this arc …

The Masked Warbler

One of the most common and widespread warblers in North American, common yellowthroats breed from southeast Alaska to Newfoundland and from the Subarctic treeline to the Gulf Coast. Though they have a preference for marshes, wet meadows and riparian thickets, these small birds also inhabit dry washes of the Desert Southwest and can be found in the lower canyons of western foothills.

The male common yellowthroat is easily identified, sporting a wide black mask across his eyes, which separates a white stripe on his forehead from his bright yellow throat and chest; females are more drab in color, with an olive back and yellow throat, but may have a faint mask as well. Common yellowthroats stay close to the ground, hunting insects among the thickets, cattails, tall grass or shrubs; their loose nest of grass and plant debris is often placed directly on the ground, where both parents incubate the eggs (usually 3 to 5). Since these warblers often remain secluded in dense vegetation, it is…

Moose in Colorado

When 12 moose were transplanted to North Park from Utah, in March, 1978, there was a general consensus among State Wildlife officials that these large herbivores had never been common in Colorado. In early 1979, another 18 moose were brought to the upper watershed of the North Platte River from Wyoming and, unchallenged by natural predators (wolves and grizzlies), the herd blossomed to 600 individuals by the mid 1990s; in fact, by that time, the moose had spread across the Rabbit Ears and Park Ranges, colonizing the Upper Colorado, Fraser and Upper Yampa river valleys.

Gratified by the success of this reintroduction program, the Division of Wildlife initiated a moose hunting program and transported some of the herd to the Upper Rio Grande Valley, near Creede. Continued expansion of the Colorado moose population has prompted additional transplantations within the State, including the establishment of a herd atop Grand Mesa, east of Grand Junction. Today, estimates of the Colorado mo…

Tropical Storm Dynamics

The development of a tropical storm is dependent upon three factors: warm ocean waters, hot, humid air at the surface and light upper-level winds. For these reasons, early season Atlantic hurricanes usually develop in the relatively shallow waters of the Gulf of Mexico, across the Caribbean and along the Southeast Coast of the U.S. While tropical waves begin to move westward, out of Africa, in early summer, they encounter cool waters in the central Atlantic and tropical storms do not usually develop; by August, the ocean temperature has increased and the peak of the Atlantic hurricane season begins, continuing through September and into early October.

Once a tropical storm develops, favorable conditions, discussed above, may cause it to strengthen into a hurricane. Conversely, if the storm moves into cooler waters, makes landfall or encounters strong upper level winds, the storm dynamics break down and the system weakens or dissipates. In some cases, favorable conditions may be re…

Humans & Heat

Native to the Tropics, we humans are better equipped to deal with heat than with the cold; indeed, given shade and adequate water, we can survive in temperatures near 130 degrees F for limited periods of time. Nevertheless, heat waves kill more Americans each year than any other form of weather, including tornadoes, hurricanes and floods.

The elderly are most prone to heat-related illness and death; their aging bodies are less capable of dissipating heat and efforts to do so place significant stress on their cardiovascular system. The other population at risk is the young athlete; blinded by the immortality of youth or prodded on by an ignorant coach, they exercise during the heat of the day and, despite fluid intake, court heat exhaustion or heat stroke.

Human tribes that inhabit hot desert regions or tropical areas know to escape from the sun during the afternoon hours. Wearing light-colored, loose-fitting clothes, they adopt the habit of mid-day siestas, retreating to shaded are…