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Showing posts from November, 2014

The Nature of Hanging Valleys

A hanging valley is generally defined as a stream or glacial valley that ends abruptly atop the steep wall of a deeper valley or sea cliff.  Such formations are especially common in glacial terrain and where the sheer wall of the deeper valley or cliff is composed of resistant rock (e.g. granite, marble, etc.).

In mountainous regions that have been subjected to glaciation, the major glacial tongues erode deep, U-shaped valleys through the range; smaller tributary glaciers feed the primary ice flow from either side.  When the glaciers melt back as the climate warms, the deep, steep-walled glacial valley is lined with hanging valleys on either side, where streams run down the shallower tributary valleys and then plunge into the deep, central valley via magnificent waterfalls; Yosemite Valley offers an excellent example of such post-glacial topography.  Of course, if the glaciated terrain has since become an arid landscape (e.g. ranges of the Great Basin) the streams and waterfalls are s…

The Gila River

Covering more than 58,000 square miles, the watershed of the Gila River includes most of Arizona south of the Mogollon Rim.  The river itself rises on the west side of the Continental Divide in western New Mexico; flowing westward into Arizona, it receives the waters of the San Carlos River within the San Carlos Reservoir, northwest of Mount Turnbull.  Continuing westward, the Gila takes in water from the San Pedro River (flowing north from Mexico), flows south of Chandler, Arizona, and then angles northwestward, passing between South Mountain and the Sierra Estrella, just south of Phoenix.  In southwest Metro Phoenix, it merges with the Salt River; the latter courses westward through the heart of the city after gathering flow from numerous tributaries that drop from the edge of the Mogollon Rim (among these are the Verde, White and Black Rivers and Canyon Creek).

Just west of its junction with the Salt, the Gila receives the waters of the Agua Fria, which rises east of Prescott and f…

Pioneers of Enlightenment

On this annual American holiday of Thanksgiving, we stop to ponder our good fortune (however meager or extravagant that might be) and to thank those who have had a positive influence on our life.  While many will direct prayers of thanks to a deity and most will focus on the love, encouragement and devotion of family and friends, we should not overlook the gifts bestowed by past members of human society.

In particular, the pioneers of science laid the foundation for human progress, insisting on objective methods in our search for truth and understanding.  Ridiculed and persecuted by the power brokers of society (a resistance that continues today), their perseverance has been vital to both the enlightenment and the very survival of our species.  In like manner, those who championed the rights and dignity of the individual, thereby stemming the forces of oppression and discrimination, fueled the spread of democracy, personal freedom and international cooperation across the globe.  And, …

Raptors in the Cold Sunshine

Clear skies and cold air enticed me down to the wooded hills and open farmlands south and east of Columbia this morning.  Besides, a steady north breeze held the promise of migrant snow geese that, like most avian travelers, take advantage of tail winds on their seasonal journeys.  Alas, no snows were spotted in the deep blue sky but thousands of starlings offered some consolation, their spectacular aerial ballets rising like smoke signals in the cold morning sunshine.

But this day belonged to the raptors.  A pair of bald eagles soared above the icy Missouri River while a second pair rested in trees near a rural park, surveying flocks of hooded mergansers and common goldeneyes that had gathered on its lake.  As usual, red-tailed hawks were abundant along the country roads, joined by several red-shouldered hawks and a large number of American kestrels.  Finally, a sharp-shinned hawk streaked across a barnyard, hoping to nab one of the sparrows that fed among the haystacks.

Other sighti…

Refuge Closed for Killing

On this cold, gray, November morning in central Missouri, I headed down to Eagle Bluffs Conservation Area on the Missouri River floodplain, hoping to observe snow geese or tundra swans.  Unfortunately, I found that most of the refuge is already closed for duck hunting, a season that seems to arrive earlier each year (surely an illusion, triggered by my biased imagination).  While I understand the need for hunting under some circumstances (to provide sustenance for isolated human cultures and to control the population of certain wildlife species....do to our annihilation of their natural predators), most hunting is purely a sport, matching one's skill against the natural abilities of the prey.  None of the duck hunters at Eagle Bluffs will starve if they miss their targets.

Of course, many will point to the contributions of Ducks Unlimited and other "conservation groups" that fund the restoration and protection of wetlands, thereby sustaining healthy populations of waterf…

The Great Appalachian Valley

The Great Appalachian Valley of North America, a series of topographic valleys separated by low divides, stretches for more than 1200 miles, from the Richelieu Valley of Quebec (which drains Lake Champlain) to the Coosa River Valley of northeastern Alabama.  While rivers have eroded (and continue to mold) the component valleys, geologic downwarping also shaped the terrain as adjacent mountains rose.

The eastern wall of the Valley is composed (from northeast to southwest) by the Green Mountains of Vermont, the Taconic Highlands of southern New England and the Blue Ridge Mountains, from south-central Pennsylvania through Virginia, North Carolina, Tennessee and northern Georgia.  The west wall consists of the Adirondacks and Catskills of New York and the easternmost ridge of the Ridge & Valley Province, from Pennsylvania to Alabama.  Some of America's most famous rivers course through sections of the Valley (including the Hudson, the Susquehanna, the Shenandoah and the Upper Tenn…

Two Cities, Two Owls

Great horned owls are the nocturnal avian predators along the Colorado Front Range, feasting on prey as large as skunks, geese and raccoons.  Not often heard during the warmer months of the year, their gruff hoots begin to echo across our Littleton farm by mid November, continuing through their mid winter breeding season and trailing off by early spring.  Utilizing abandoned hawk or magpie nests (or drum nests placed by humans), these powerful raptors are perhaps best observed in late winter, when mom and her downy youngsters stare down from their roost in a cottonwood grove.

In Columbia, Missouri, our neighborhood is amidst a network of wooded stream valleys and barred owls are far more common than their larger cousins; delivered throughout the seasons, their mellow, questioning calls may be heard day or night.  Barred owls lack the "ear tufts" of great horned owls, have dark eyes and often tolerate close approach, peering down from a trailside tree as hikers pass below.  T…

Snow Disaster in Buffalo

The poster child for lake-effect snow events struck South Buffalo, New York, this week, dropping up to six feet of snow.  According to local weather officials, this is the greatest one-day snowfall in at least 40 years; given the fact that the Great Lakes have existed for about 12,000 years, it's anyone's guess where this crippling storm falls on the spectrum of past lake-effect snow events.

Frigid air, moving west to east over the relatively warm waters of Lake Erie, produced the spectacular accumulation of snow.  Once the wind shifted from a more southerly direction, the skies cleared and the snow machine was shut down; unfortunately, that wind shift is expected to be brief and lake-effect snows are forecast to resume in the Buffalo area, perhaps dropping another two feet or more.

Lake-effect snow bands, like snow-guns used at ski areas, can produce dramatic snow accumulation in one linear region with little or no snowfall to either side of that band; though South Buffalo wa…

Pipeline to Oblivion

Political, corporate and public support for the Keystone Pipeline is a direct repudiation of efforts to reduce fossil fuel consumption across the globe.  Touting the economic and societal benefits of the project, supporters voice little concern for its environmental impacts, including our continued reliance on a product that threatens the welfare of our planet.

The tar sands of northeastern Alberta, Canada, lie within Cretaceous sediments of the Athabasca River Valley.  Extraction of their heavy crude has involved both open pit mining and in situ techniques (which require large volumes of water, diverted from the river).  Both forms of extraction threaten the regional environment, either via direct destruction of boreal bogs and forest or by pollution of the river and its tributaries.  Of course, transportation of the heavy crude in a pipeline that crosses the American Heartland raises the possibility of spills in rivers, prairies, wetlands or vital agricultural areas along the way.

B…

A Tribute to Stephen Hawking

Yesterday, my wife and I saw The Theory of Everything, the story of Steven Hawking's rise from a socially awkward graduate student to an international celebrity and pioneering genius in the field of theoretical physics.  His accomplishments, of course, unfolded despite the ravages of ALS that eventually confined him to a wheelchair and necessitated the use of a computerized voice machine; though initially advised that he had two years to live, Steven Hawking continues to lend his intellect and insight at the age of seventy-two.

While some reviewers have criticized the movie for its simplified treatment of Hawking's theories on time, black holes and the origin of the Universe, I thoroughly enjoyed and highly recommend the film; it effectively blended the roles that love, intelligence and perseverance played in his development as a physicist and as a human being.  It also highlighted Hawking's view that mysticism has no place in science while relating his conviction that the…

Harlan's Hawk

Harlan's hawk is a large, dark-plumaged buteo that breeds across Alaska and Northwest Canada.  Once considered a distinct species, this powerful raptor is now classified as a subspecies of the red-tailed hawk, which ranges across most of North America.

Come autumn, Harlan's hawks head primarily for the Southern Plains, from the base of the Front Range to Arkansas and Texas, though individuals have been observed throughout much of the U.S., especially west of the Mississippi River; fortunately, one of these northern predators has been wintering on or near our Littleton, Colorado, farm over the past few years.  His bulky form is often observed on a phone pole or in a large tree, searching the fields and pastures for mice, voles or cottontails.  Oblivious of the frigid air and snow, he is an impressive representative of the vast northern wilderness that is his home.

Indeed, one of the benefits of birding is the opportunity to enjoy the seasonal presence of wild creatures that spe…

Mount Pavlov Eruption

Mount Pavlov, 8560 feet, is a stratovolcano on the Alaskan Peninsula, some 600 miles southwest of Anchorage.  It formed within the last 10,000 years, on the northeast edge of the Emmons Lake Caldera (the remnants of an ancient volcanic explosion); like all of the Aleutian Volcanoes, it is the product of subduction, as the Pacific Plate dips beneath the North American Plate, causing its edge to melt and fuel volcanism.

The most active volcano in Alaska, Mount Pavlov has experienced numerous eruptions, most of which have been relatively benign due to both the volcano's structure and its remote location.  The current eruption began earlier this week with little fanfare; however, over the past 24 hours, Mt. Pavlov's ash plume has intensified, rising 30,000 feet above sea level and threatening air traffic in the region.

Such is the nature of "natural disasters" across the globe.  While the physical evolution of Planet Earth continues, just as it has for 4.6 billion years,…

A Wintry Waterfowl Count

For the first monthly waterfowl count of the winter season, wintry conditions enveloped South Platte Park in Littleton, Colorado.  Following a one day respite from this week's frigid weather, a second phase of the Polar Express is pushing across the State and light snow developed along the Front Range early this morning.

Needless to say, the cold air, blowing snow and steam-shrouded lakes made the counting difficult at times.  Nevertheless, our group encountered a large number and variety of species on the South Platte and its floodplain lakes; Canada geese, gadwalls, northern shovelers and American widgeon were most abundant, joined by mallards, lesser scaup, buffleheads, common goldeneyes, hooded mergansers, northern pintails and green-winged teal.  Other sightings included pied-billed grebes, a lone western grebe, a muskrat and a rough-legged hawk.

As the lakes freeze over during the winter months, some of the waterfowl will head further south but most will simply move to the t…

A Frigid Morning at Red Rocks

Red Rocks Park, in the foothills west of Denver, is best known for its outdoor, rock-walled amphitheater, which, over the years, has hosted a wide variety of concerts and other forms of entertainment.  To birders and naturalists, the Park is also known as an excellent place to explore the flora and fauna of the Front Range shrub zone.

Today, my friend and I arrived at the snow-laden landscape of Red Rocks Park by mid morning; the air was calm but the temperature was 8 degrees F.  Since he is a wildlife photographer, we headed straight for the feeder area behind the Trading Post, well known as a magnet for resident birds, migrants, wintering species and rare vagrants.  Though recent reports indicated sightings of golden-crowned sparrows at the Park, we failed to observe them today; neither did we see rosy finches, which often invade Red Rocks after winter storms rake the mountains.  At the feeders, four races of dark-eyed juncos were the most numerous visitors, followed by black-capped…

The Rosetta Mission & Climate Change

Today, ten years after its launch and at the end of a 4 billion mile journey, the Rosetta spacecraft successfully landed its Philae probe on a comet.  The latter was traveling at 85,000 miles per hour and the rendezvous occurred 311 million miles from Planet Earth.  Scientists hope to learn more about the birth of our solar system from data collected on the comet's surface.

This stunning achievement is the culmination of a project that began long before liftoff and, of course, owes its success to the knowledge that we humans have accumulated over more than five centuries.  Few would deny that this feat is just the latest in a long history of monumental scientific achievements, all of which have drawn from our understanding of the laws of nature.

Yet, many who applaud the success of the Rosetta mission remain unwilling to accept the scientific evidence of global warming.  Whether motivated by religion, politics or personal interests, they choose to ignore (if not ridicule) science …

Escape from the Frigid Upslope

Facing a cold, cloudy day with intermittent flurries (courtesy of this week's Polar Express), we and our guests escaped to the Western Slope of the Continental Divide.  Climbing through the frigid fog along Interstate 70, we left the upslope clouds just beyond Georgetown, Colorado, which sits at 8500 feet.  From there westward, we enjoyed sunny skies and relatively mild November conditions.

We ended up in Vail for lunch and an afternoon of hiking and birding; highlights of the latter included flocks of cedar waxwings and pine grosbeaks, in town to feast on the varied crops of berries.  We looked in vain for common dippers along Gore Creek but did encounter a ruby-crowned kinglet, seemingly a bit tardy for his journey to the south.

Following our pleasant afternoon west of the Divide, we returned to Metro Denver, re-entering the upslope fog at Georgetown and eventually crawling from the foothills and through the city, where late day snow and temperatures in the teens (F) created icy…

Watching Winter Arrive

This morning dawned clear, sunny and mild along the Colorado Front Range.  Knowing that a potent cold front was on its way, we introduced our visitors to several State Parks, hoping to complete our tour before the Arctic blast arrived.

A quick drive through Chatfield State Park was followed by a hike at Roxborough State Park; enjoying the wildlife and scenic rock formations at Roxborough, we could see a wall of clouds building to our north.  Though it was too warm to hike in a heavy sweatshirt or jacket, we knew that the warm sunshine (64 degrees F by mid morning) would soon give way to wintry conditions.

As the clouds pushed southward, gusty winds produced dust storms across Metro Denver and we headed for the hills, climbing through Deer Creek Canyon and then angling southwestward on U.S. 285.  We were headed for Staunton State Park, on the south side of the Mt. Evans massif and west of a high ridge that cuts across Conifer, Colorado.  There, protected from high winds and the rapidly…

Return of the Bark Birds

A pair of brown creepers returned to our central Missouri neighborhood this week and will be observed on occasion throughout the colder months.  After nesting in the Northwoods of Canada, southern Alaska and the Great Lakes region and southward through the Appalachians and Western mountains, these small, slender birds leave their coniferous homeland to winter in mixed woods throughout much of the U.S.

Commonly encountered in parks and suburban areas, brown creepers favor areas with large trees where they circle up the trunk, searching for hibernating insects and spiders.  Nearing the top of the trunk or one of its major branches, they fly to the base of another tree and begin to climb and search once again, picking through the bark with their curved bill.  During their winter visit, creepers may also turn up at suet feeders and frequently join mixed flocks of chickadees, titmice and downy woodpeckers in the barren woods.

Resembling pieces of bark themselves, brown creepers are monogam…

Water: Sculptor of the Earth

While plate tectonics rearranges the Continents, lifts mountain ranges and ignites volcanism, water sculpts the surface of Planet Earth.  Falling as rain, snow or ice pellets and lashing the coastlines as waves, this vital substance erodes and shapes our landscapes.

Whether moving as liquid water in rivers and streams or as solid ice in glaciers, water sculpts the mountains, plateaus and mesas of our planet, carving cirques, canyons and valleys and then spreading that debris across the lowlands or delivering it to lakes and oceans.  Along the margins of the Continents, wind-driven waves mold the shorelines, producing cliffs, sea stacks and barrier islands.

Of course, vegetation modifies this erosion in many regions, stabilizing soil and dunes, slowing and filtering the flow of streams and absorbing excess precipitation.  Unfortunately, we humans have a history of destroying that protection by draining wetlands, clearing forests and plowing prairies, augmenting the risk of destructive …

Africa's Aquatic Dinosaur

Last evening, NOVA, on PBS, focused on the discovery and evaluation of Spinosaurus fossils, the largest carnivorous dinosaur yet unearthed and the only one known to have been semi-aquatic.  Larger than Tyrannosaurus rex, Spinosaurus lived in the Saharan Desert region of North Africa, some 95 million years ago.  Its fossils have been found in a layer of late Cretaceous sandstone which also contains the fossils of numerous marine creatures, indicating that a shallow sea covered much of the region during that period.

Characterized by a long, crocodilian snout, relatively large forelimbs and a large, boney fin on its back, Spinosaurus would have been too top-heavy to walk upright like T. rex; indeed, paleontologists have concluded that it was primarily aquatic (scouring the shallows for large fish, sharks and other marine life) and only came ashore to sleep, nest or perhaps to feast on small terrestrial vertebrates.  Its conical teeth and flat feet (both seen in crocodilians) favor this h…

The Anti-Science Coalition

Back when foresighted individuals such as Galileo and Copernicus led humanity toward scientific enlightenment, the Church condemned their theories and attempted to quash their influence.  Over time, as science fueled the industrial and technologic revolutions, religious organizations were forced to acknowledge that the theories of those intellectual pioneers had been valid; nevertheless, where scientific evidence directly undermines the basic doctrines of religion (e.g. evolution), the Church, in its varied forms, continues to reject the message.

Over the past few decades, political forces have joined the anti-science coalition, specifically in the area of global warming.  Protecting industries that fund their livelihood (i.e. the oil, gas and coal companies), conservative politicians ridicule the scientific evidence put forth by climatologists.  In doing so, they further diminish the value of science in the collective mind of an uneducated public.

Since the days of Galileo and Copern…

Anticipation on the Eastern Plain

Driving to Cincinnati today, I crossed the eastern portion of North America's Glaciated Plain, which stretches from western Illinois to central Ohio.  It is a relatively flat landscape of crop fields and hay pastures (once a tallgrass prairie), laced with streamside woodlands.

On this calm, mild November day, the region and its wildlife seemed to be laying low, awaiting the turmoil of the coming season.  The spectacular October colors were fading toward brown and the trees had undergone a variable degree of defoliation.  Red-tailed hawks perched in trees along the highway or lazily soared above the drying fields while flocks of turkey vultures tilted in the gentle southerly breeze.  Migrant waterfowl speckled the numerous farm ponds and groups of crows strutted through the corn stubble, picking at waste grain and sluggish grasshoppers.

As a traveler through that rural landscape, I sensed anticipation in its wild residents.  They may enjoy another week or two of mild conditions but…

Migratory Woodpeckers

Mention migrant birds and most of us think of waterfowl, shorebirds, seabirds and a wide variety of songbirds; few would think to include woodpeckers in that mix.  Indeed, most woodpeckers are permanent residents of their home territory, perhaps descending from higher elevations or moving among seasonal habitats but not leaving for more southern climes as winter approaches.

The primary exceptions are the sapsuckers, which prefer to feast on insects and sap.  Yellow-bellied sapsuckers breed across Canada, the Great Lakes region and New England but winter in the Southeastern States and Mexico.  Red-naped and Williamson's sapsuckers summer in the Rockies and Intermountain West but winter from the southern Colorado Plateau and Desert Southwest into Mexico; some Williamson's sapsuckers are permanent residents of the Sierra Nevada range.  Finally, red-breasted sapsuckers breed in British Columbia, southeastern Alaska, the Pacific Northwest States and the Sierra Nevada; most leave mo…

Football Weather

As we move deeper into autumn, the term "football weather" is frequently heard.  In many cases, it is used to define unpleasant conditions that devoted fans must endure, including torrential rains in the Deep South, frigid temperatures across the Northern Plains or blowing snow in the Mountain States.  More often, however, it refers to crisp, breezy days, the air faintly scented with barbecue fumes or wood smoke.

Today, it is the latter that envelops Columbia, Missouri, where the Tigers host the Kentucky Wildcats.  Not heading to the game, I'll catch parts of it and other contests on the TV but find it impossible to remain glued to the couch on such a beautiful autumn day, our first chilly afternoon of the season.  After all, there are leaves to rake, feeders to fill and fresh air to inhale.

Like many half-hearted fans, I enjoy football primarily due to the season in which its games take place. In the American Heartland, football weather is synonymous with the glorious d…