Monday, April 29, 2013

Late April at Mt. Falcon

Late April is a great time to visit the Transition Zone forest of the Colorado Front Range foothills.  Also known as the Montane or Yellow Pine Zone, this forest of open ponderosa pine woodlands (on south facing slopes) and dense Douglas fir forest (on shaded hillsides) stretches between elevations of 7000 and 9000 feet.  One of the better locations to explore this life zone is Mt. Falcon Park, in Jefferson County, just west of Metro Denver.

Yesterday morning, the woodlands of that Park were alive with the sound of ravens, Steller's jays, gray-headed juncos, mountain chickadees, hairy woodpeckers and all three nuthatches (white-throated, red-breasted and pygmy).  Mountain and western bluebirds hunted on the meadows, joined by Townsend's solitaires, robins, black-billed magpies and chipping sparrows.  White-throated swifts zoomed along the canyon walls, not yet joined by violet-green swallows; other summer residents yet to arrive include western tanagers, MacGillivray's warblers, black-headed grosbeaks, lesser goldfinches, solitary vireos and a host of mountain flycatchers.  Though Williamson's sapsuckers and blue grouse were surely present, I did not encounter them on my visit.

Common mammals of the Transition Zone include Colorado chipmunks, golden-mantled ground squirrels, Abert's squirrels and mule deer; while bobcats, black bears and mountain lions patrol Mt. Falcon, they are rarely seen.  Birders and naturalists who appreciate solitude are advised to visit the Park on weekdays or early on weekend mornings since crowds of bikers, hikers and dog-walkers are common by mid morning, especially on warm-weather weekends.

Sunday, April 28, 2013

Earth's Evolving Landscape

From the moment of its formation, 4.6 billion years ago, Planet Earth's surface has been continuously molded by natural forces.  Plate tectonics has opened and closed oceans, lifted mountain ranges, torn continents apart and produced a wide variety of volcanic terrain.  At the same time, streams, rivers, wind, waves and glaciers have been eroding the landforms, leveling highlands, sculpting rock formations, opening caves, carving canyons and revising shorelines.  Finally, the interplay of climate, latitude, soil condition, wildfire, precipitation and other factors determine the changing mosaic of surface vegetation which, in turn, governs regional fauna populations.

During our brief lifespans we barely notice significant changes in Earth's landscape except for features that we, as a species, have produced: reservoirs, canals, man-made canyons, tunnels, agricultural fields and construction related to our towns and cities.  Active volcanic eruptions, earthquakes, floods, rockfalls, tsunamis, mudslides, hurricanes and other natural phenomena offer intermittent evidence of the forces that shape our planet but the concept of plate tectonics is difficult to comprehend during our brief lives.

Indeed, it is our short-term perspective that tricks us into believing that we can control (or at least manage) the forces of nature.  Convinced that we can prevent flooding with dams and levees, we build cities on floodplains.  Confident that we can divert water from distant rivers and underground aquifers indefinitely, we develop resorts, golf courses and sprawling suburbs in desert landscapes.  Oblivious to the power of hurricanes and tropical storms, we construct homes along coastlines and on barrier islands.  Betting against rockslides, avalanches and wildfires, we establish towns on rugged mountains slopes.  Most of us luck out; others do not.  In the end, the erratic yet relentless evolution of our planet continues and nature neither targets nor spares human communities.

Saturday, April 27, 2013

Front Range Waders

As the days lengthen and the weather warms, some birds return to the Colorado Front Range that may seem out of place in a State known for prairie, mountains and canyons.  Nevertheless, herons, egrets and ibis have long been residents of this region and man-made reservoirs have significantly increased their population along the South Platte and Arkansas River Valleys.

Great blue herons and a small number of black-crowned night herons are year-round residents of the Front Range urban corridor.  The population of the latter increases dramatically during the warmer months when they are joined by snowy egrets, green-backed herons, American bitterns and white-faced ibis.  Cattle egrets are also summer residents along the Front Range, attracted to the region by the combination of cattle ranches and reservoirs.  In late summer, great egrets and yellow-crowned night herons may also wander into the State and occasionally turn up along the Front Range.

The presence of these waders, generally associated with Southeastern and Gulf Coast States, likely goes unnoticed by many (if not most) human residents of Colorado.  Birders, fishermen and naturalists are certainly familiar with their presence but newcomers, visitors and novice birders are often surprised to find herons, egrets and ibis along the foot of the Rocky Mountains.

Friday, April 26, 2013

Spring Arrives at Chatfield

Though it's a month late, spring has finally taken charge at Chatfield State Park, southwest of Denver.  On my visit this morning, I focused (as usual) on the backwater areas of the reservoir and along the ponds, wetlands and riparian woods that flank the South Platte River, south of the lake.

Scattered flocks of American white pelicans and western grebes graced the open waters, joined by double-crested cormorants, common mergansers and wood ducks.  Several ospreys perched above the shoreline or fished on the reservoir while lesser yellowlegs and spotted sandpipers foraged along the sandy rim and mudflats; in the shallows, chorus frogs, having recovered from our wintery setback, delivered their rising calls.  Though the cottonwood groves and willow thickets remain devoid of leaves, they were filled with songbirds and woodpeckers, including northern flickers, downy woodpeckers, house wrens, magpies, house finches and an abundance of yellow-rumped warblers; northern orioles and other summer residents should arrive by early May.

In addition to the ospreys, raptors included red-tailed hawks and sharp-shinned hawks and a large flock of turkey vultures soared above the Park.  Out on the grasslands, western meadowlarks, vesper sparrows and horned larks were observed, now free to forage in a snowless landscape.  While snow may yet fall (through mid May in some years), the threat of severe cold has likely passed and an explosion of life will encompass Chatfield State Park in the coming weeks.

Thursday, April 25, 2013

A Welcome Thrush

No sooner had the recent blanket of snow melted from our Littleton, Colorado, farm than a Swainson's thrush appeared, foraging in a flower bed.  Common migrants along the Front Range urban corridor, especially in spring, this spotted thrush breeds in coniferous forests of southern Alaska, Canada and the mountain ranges of the Western U.S.

Distinguished from other spotted thrushes by its dull, brown-olive back, its faded breast spots and its buff-colored eye ring, Swainson's thrush also delivers a unique, rising song.  Like its close cousins, it feeds primarily on the ground, consuming both insects and berries; unlike the others, it also feeds in the lower branches of trees and, at times, engages in fly-catching behavior.  Nests are placed in the understory shrubs of coniferous woodlands and 3 to 4 eggs are generally produced.  Come fall, Swainson's thrushes head to Mexico, Central America or South America for the northern winter.

Our visitor last evening was a welcome sight indeed, the first summer songbird to grace our property during this cold, snowy spring; hopefully, his presence was a sign that the late incursions of winter have finally come to an end.

Wednesday, April 24, 2013

The Cost of Extravagance

While human society seems to value some professions with little attention to their social importance, we cannot deny anyone the income that his/her talent and hard work may produce within a free and open market.  How that money is spent, on the other hand, has a significant impact on the welfare of society as a whole.

Though legal restrictions on the various forms of consumption would be inappropriate, one hopes that those with high incomes have a social conscience.  After all, the willingness of many wealthy individuals to support education, creative arts, community recreation, social services and environmental programs has long been vital to the welfare of urban and rural communities.

Yet, extravagance persists.  Massive homes, luxury-focused lifestyles, excessive personal consumption, outrageous galas and preferential treatment by both the political and private sectors have a negative impact on the welfare of human society and on the health of natural ecosystems.  Indeed, the greatest threat to our environment is the excessive (and often needless) consumption of natural resources, leading to resource depletion, pollution, the destruction of natural habitat and the loss of sensitive species.  While the rewards of hard work should not be denied, the personal choice to refrain from extravagance is a gift to others and to our home planet.

Tuesday, April 23, 2013

Recovery in Sight

As light snow continues to fall along the Colorado Front Range and overnight lows dip near twenty degrees F, the signs of spring are few and far between.  During our brief warm interludes, the lawns and pastures harbor the greenery of the season but the shrubs and deciduous trees remain barren.  By now, the pears, wild plums and crab apples should be in full bloom but flowering is limited to the grape hyacinths, dandelions and purple mustard.

Some summer birds, including cormorants, western grebes, bluebirds and tree swallows grace the Front Range but seem out of place in the snowy landscape; other summer songbirds have likely been stopped in their tracks or turned back by the wintery weather.  While April snowstorms are common in this region, the intense cold, courtesy of recurrent atmospheric troughs across the Intermountain West, has essentially put spring on hold; unfortunately, for areas to our east, these same troughs have directed severe thunderstorms and flooding rains across a broad swath of the Midwest.

For those of us in Metro Denver, recovery is in sight.  Following another day of snow showers and a near-record overnight low, a significant warmup is forecast for the coming week.  The high April sun and a southwesterly breeze will push our afternoon highs into the seventies and the sights, sounds and fragrance of spring should spread across the Front Range.  Of course, within a month or so, we'll likely be fretting about the heat and drought.

Sunday, April 21, 2013

Bluebirds in Colorado

During the warmer months, generally from April through early October, Colorado hosts all three species of North American bluebirds.  Arriving in early-mid spring, they inhabit wooded meadows and ranchlands, nesting in tree cavities or man-made nest boxes.  Primarily insectivorous in spring and summer, they also consume berries, especially during the fall and winter months.

Western bluebirds are found from the Front Range urban corridor to the western canyonlands of Colorado, favoring open woodlands of the foothills and mountain parklands.  Mountain bluebirds, sky blue in color, inhabit the upper foothills and mountains and are often seen above timberline.  Eastern bluebirds, recent immigrants to Colorado are primarily found along the eastern edge of the State; however, they seem to be expanding that range along the South Platte and Arkansas River corridors and small numbers have turned up in Front Range towns and suburbs.

Eastern bluebirds that summer in Colorado winter across the Central and Southern Plains while western and mountain bluebirds winter in the Desert Southwest and northern Mexico; however, some mountain bluebirds wander eastward during the colder months, occasionally turning up on the Great Plains or in the Midwest.  Novice birders who visit Colorado may confuse male lazuli buntings or blue grosbeaks with bluebirds; the former inhabit foothill shrublands and brushy canyons while the latter are found on grasslands of Colorado's eastern plains and piedmont.

Saturday, April 20, 2013

South Platte Crossroads

Granted a reprieve from our wintery spring weather, I decided to visit South Platte Park, a greenbelt of ponds, meadows and riparian woodlands along the South Platte River.  Like our weather over the past week, a mix of winter and spring was evident across that riverside preserve.

Many winter ducks, including buffleheads, lesser scaup and green-winged teal had yet to depart for the north, joining permanent residents such as mallards, gadwall, shovelers, common mergansers and wood ducks on the river and ponds.  They were also accompanied by a number of summer residents that now grace the valley; among this group were double-crested cormorants, western grebes, cinnamon teal and tree swallows.  Lesser yellowlegs, common migrants in Colorado, were also seen, feeding along the sandy shores.

As in most parts of our country, mid-April is a time of transition, when the signs of winter fade from the landscape and the greenery of spring begins to accelerate.  Unfortunately, due to our recent cold, snowy weather, the leafing of shrubs and trees is well behind schedule and one wonders if our summer birds, arriving from wintering grounds in warm, southern climes, take notice of the barren woodlands.

Friday, April 19, 2013

Australia's Great Central Ranges

While the Great Dividing Range runs up the east edge of Australia and various highlands are scattered along its periphery, the Continent is dominated by flat terrain; there are certainly no ranges comparable to the Andes, the Rockies, the Alps or the Himalayas in Australia.  However, that has not always been the case.

Back in the Precambrian Era, about 1 billion years ago, a massive, snow-capped range was lifted across the center of Australia, stretching east to west; while erosion began to demolish this lofty range as soon as it formed, subsequent uplifts occurred 500 million years ago (MYA) and 300 MYA.  Today, the remnants of those orogenies, known as the MacDonnell Ranges, are a swath of relatively low ridges and hills (with maximum elevations below 5000 feet) that stretch for 400 miles across the southern edge of the Northern Territory, just north of Alice Springs.  Another great mountain range, the Petermann Ranges, crumpled skyward about 600 MYA and its residual swath of hills and ridges (all below 4000 feet) now stretch about 200 miles, from the east-central border of Western Australia to the northwestern corner of South Australia.

These great ranges were forced up by continental collisions back when Australia was attached to Antarctica and, at times, to other land masses.  Once Australia broke from Antarctica (by 80 MYA) and drifted into prolonged isolation, it was no longer subjected to such tectonic forces and the great central ranges gradually eroded, spreading vast aprons of sediment across the Red Center of the Continent.  Today, Australia sits near the center of its vast tectonic plate, far from the subduction and collision zones that ring the edge of the plate.  Those who hope to see a towering alpine range in Australia will have to wait until one of its bordering oceans stops spreading and completely subducts, allowing the Continent to collide with Antarctica, Asia or, perhaps, the new Continent of East Africa.

Thursday, April 18, 2013

The Spanish Peaks

In southern Colorado, southwest of Walsenburg, two prominent cone-shaped peaks rise east of the Sangre de Cristo Range.  In light of other volcanic features throughout southern Colorado and northern New Mexico, one might think that these large mountains are extinct volcanoes.

In fact, the West and East Spanish Peaks were intruded as magma beneath the surface during the late Oligocene Period, some 25 million years ago.  Encased within Cretaceous and early Tertiary sediments, the massive plutons and their lateral dikes of cooled magma rose during the Miocene-Pliocene Uplift and have since been uncovered by the forces of erosion.  Similar Tertiary laccolithic mountains include the La Sal, Abajo and Henry Mountains of southeastern Utah.

The higher elevations of both mountains are now protected within the Spanish Peaks Wilderness Area; East Spanish Peak rises to almost 12,700 feet while the summit of West Spanish Peak is just over 13,600 feet.  Visible from great distances throughout southeastern Colorado, these majestic peaks guard the eastern entrance to La Veta Pass, traversed by U.S. 160.  West of the pass, the highway drops into the high desert terrain of the San Luis Valley, drained, in part, by the Rio Grande River.

Wednesday, April 17, 2013

Iran's Subduction Earthquake

Yesterday's magnitude 7.8 earthquake in southeastern Iran, the most powerful in that country in more than 50 years, occurred near the Pakistan border in a region of complex plate tectonics.  Caught between the Arabian Plate, which is moving northward to collide with the Eurasian Plate, and the Indian Plate, which has been colliding with the Eurasian Plate for at least 55 million years, a fragment of oceanic crust, known as the Makran Wedge, is forced to subduct beneath the Iran-Pakistan border region.

The opening of  the Red Sea, which began about 40 million years ago, split the Arabian Plate from the African Plate.  This rifting extended eastward, forming the Gulf of Aden, about 20 million years ago, and southward through Africa to produce the East African Rift, which will eventually split that continent.  As the Red Sea and Gulf of Aden continue to open, the Arabian Plate is forced northward, closing both the Persian Gulf and the Gulf of Oman.  Caught between the Arabian and Indian Plates and forced northward as well, the Makran Wedge began to subduct beneath southern Eurasia during the Miocene Period (about 20-15 million years ago), producing the Baluchistan Volcanic Arc across southeastern Iran and eastern Pakistan.

While most Iranian earthquakes arise from compression between the Arabian and Eurasian Plates and most earthquakes in Pakistan result from the collision of the Indian and Eurasian Plates, yesterday's earthquake developed within the Makran subduction zone, about 50 miles deep, where that oceanic wedge continues to dive beneath the southern edge of Eurasia.  Tremors from the powerful quake were felt throughout much of the Middle East.

Tuesday, April 16, 2013

Our Response to Terror

Following episodes of terrorism, as occurred at the Boston Marathon yesterday, we immediately empathize with those caught up in the tragedy.  In an effort to allay our own fear, we seek every detail of the event, glued to television and online reports, hoping to somehow understand the reason for the act and to learn that progress is being made toward arresting those responsible for the tragedy.

Our first instinct is to blame groups known to employ terrorism in order to advance their agendas.  As a result, we are quick to focus on individuals who, based on their race or nationality, invite suspicion.  In addition, we look for others to blame, including public officials who, in our minds, might have done more to prevent the tragedy.  While, in a free society, absolute protection from determined terrorists is impossible, we want to know that security failures somehow enabled the horrendous act.

Finally, and most tragic of all, we begin to accept limitations on our freedom that might prevent such events in the future.  While certain security measures have become a necessary part of modern life, a willingness to alter our lives and our social traditions in response to terrorism acknowledges its effectiveness and encourages its use.  As difficult as it may seem in the wake of this most recent tragedy, our best protection is to carry on with life, undaunted by the tool of fear.

Monday, April 15, 2013

Drought Tolerant Shrubs

In our effort to reduce water consumption, it is important to landscape our property with plants that do not require irrigation (i.e. plants that thrive with their natural allotment of rain and snow).  Plants native to one's home environment are thus the ideal candidates.

Here along the Front Range urban corridor, shrubs native to the Piedmont and lower foothills are used for natural landscaping; these include rabbitbrush, sand willow, chokecherry, serviceberry, sumac, Gambel oak, wild cherry, mountain mahogany, potentilla, junipers and others.  On our Littleton farm, we also have a wide variety of non-native, drought-tolerant shrubs; lilacs, wild plum, Oregon grape, spirea, Hibiscus syriacus (Rose of Sharon), cacti and a variety of roses thrive in the dry, sunny climate of Colorado.

In addition to their role in saving water, the above shrubs provide a diversity of color and attract a wide variety of wildlife.  By expanding shrub borders and using native grasses for limited lawn space,  we multiply those benefits, reduce our yard work and increase the availability of natural landscape for our wild neighbors.

Saturday, April 13, 2013

Water & the Southwest

Faced with a persistent drought and a below-average snowpack, superimposed on our arid climate, those of us who live in the American Southwest need to develop a more realistic approach to our worsening water shortage; indeed, global warming is expected to dramatically accelerate the problem.

This year, Metro Denver has imposed water restrictions, limiting the irrigation of lawns to two days each week.  Yet, one wonders why we need to be watering lawns, parks, golf courses and sports fields at all.  None of these grassy oases are natural and none are vital to the welfare of human society.  While there has been a movement to plant drought tolerant grasses, shrubs and trees, there is no reason to permit unnatural watering of our landscapes; after all, we chose to live in this sunny, dry climate and we should be willing to accept the natural features of our arid ecosystem.

Beyond limited water use and conservation measures, attention must be paid to expanded housing, industrial development and continued population growth in a region that our water resources cannot sustain.  While technology, including desalination, may provide some relief, we are destroying natural ecosystems with our boundless diversion of water from the Colorado River and other streams.  The time has come to take a more dramatic and realistic approach to this human-induced crisis.

Friday, April 12, 2013

The Shrike and I

Earlier this week,  a spring snowstorm expected to arrive on the following day, I opted for a drive into the mountains west of Denver.  With no particular destination in mind, I ended up at Geneva Park, a subalpine parkland between the Mt Evans Massif and the Continental Divide.

Parking along a graveled road, I got out of my pickup to enjoy the magnificent scenery, the cool, fresh air and the sights and sounds of the high country.  Puffy clouds raced eastward against a clear, blue sky and faint showers of snow, blowing down from the Divide, swirled across the meadow.  Except for wind in the trees, an occasional jet drifting toward DIA and the distant calls of ravens, all was quiet in that remote valley.  Scanning the willows and forest edge with my binoculars, I soon discovered a northern shrike, perched atop a barren aspen tree.  Though surely an illusion, we seemed to be the only creatures within that vast mountain landscape.

Visiting balmy Colorado for the winter, he would soon return to his breeding grounds in the open taiga of northern Canada or Alaska.  On that early spring afternoon, the shrike was likely scanning the grassland for a small rodent or songbird to fuel his coming migration; despite his serene manner and beautiful, clean-edged plumage, this "butcher bird" would eventually find a victim, drop from his perch, crush its neck with his thick, hooked bill and impale its carcass on a thorn, sharp twig or wire fence for later consumption.  Before such violence was unleashed by may sole companion, I had to depart that tranquil parkland; my dinner was waiting at Panera.

Thursday, April 11, 2013

Fossils & Catastrophe

While the fossils of aquatic plants and animals are often preserved at the bottom of lakes and oceans during the natural process of sedimentation, the fossils of terrestrial plants and animals often reflect the occurrence of a natural catastrophe.

Were it not for sudden events that rapidly bury the remains of terrestrial plants and animals, their components would be consumed by predators and scavengers, degraded by natural decomposition and scattered by the forces of wind and water.  The best fossils are thus found where catastrophe rapidly entombed the victim, whether dead or alive as that process unfolded.  Examples include flash floods, mudslides, avalanches, sandstorms or volcanic eruptions that encased the plants or animals in debris before predation or decomposition occurred.  Some of the most complete anatomic preservations were produced when an animal (mammoth, human) was suddenly enveloped in ice or snow, having succumbed to a blizzard or having fallen into a glacial crevasse, frozen in time until a warmer climate revealed their fate.

Such natural catastrophes, spaced throughout geologic time, have offered valuable insight into the evolution of life.  Since the timing of the event corresponds to the age of the sediment in which the fossils are found, the sequence of natural history is written in the rock strata of Planet Earth.  Of course, tectonic forces may have since moved those sediments from river basins to mountain summits but the story remains intact.

Wednesday, April 10, 2013

Eolian Jurassic Sandstones

Three eolian (wind-deposited) Jurassic sandstones make a major contribution to the spectacular scenery of the Colorado Plateau.  These strata, initially emplaced as dune fields, have compacted into unique sedimentary rocks, cemented by heat and pressure over more than 150 million years.

The oldest of these is the Wingate Sandstone, deposited at the dawn of the Jurassic (about 200 million years ago); in most areas, it sits atop late Triassic redbeds of the Chinle formation.  The Wingate forms massive red cliffs with vertical striations, often giving it a curtain-like appearance.  Atop the Wingate, the Kayenta formation of horizontal siltstones, conglomerates and sandstone separates it from the second major eolian sandstone of the Jurassic, the Navaho Sandstone.  White to pale pink in color, the Navaho has horizontal striations and also forms prominent cliffs; however, it erodes into rounded domes, wavy ledges and curved slickrock formations, many of which are honeycombed and pock-marked by wind-driven sand.  The Carmel Formation, a thin layer of shale and limestone, sits atop the Navaho Sandstone, separating it from the Entrada Sandstone, a salmon-colored eolian sandstone that, like the Navaho, erodes into rounded outcrops.

Exposures of the Wingate and Navaho Sandstones are widespread across the Colorado Plateau; both form cliffs in Canyonlands National Park, in the Escalante River Canyon and on the Vermillion Cliffs, north of Kanab, Utah.  Wingate Sandstone forms the sheer walls of the Colorado National Monument while Navaho Sandstone forms the spectacular cliffs of Zion Canyon, the domes of Capitol Reef National Park and the towering rock walls along western portions of Lake Powell.  Entrada Sandstone also outcrops in Colorado National Monument but is most famous for its many arches and rock formations throughout Arches National Park.  Once desolate dune fields, these magnificent sandstones now invite exploration and their images grace calendars and coffee table books across the globe.

Tuesday, April 9, 2013

Close but no Blizzard

As one who practiced inexact science for more than 36 years, I am always hesitant to criticize meteorologists when their forecast is less than completely accurate.  After all, there are many factors involved in making such forecasts and modern computer models, while steadily improving, are not infallible.  So, when, after days of warnings that Denver would be buried under a foot or more of snow and be faced with a raging blizzard, Winter Storm Walda passed through our region without the expected armageddon, I was not overly surprised.

The first clue that our official forecast might not be accurate occurred yesterday afternoon as severe thunderstorms, some tornadic, ignited in northeastern Colorado.  Pacific storms that generate heavy upslope snows in Metro Denver generally move eastward along the Colorado-New Mexico line and the brunt of their severe weather develops across the Southern Plains.  The central low of Walda and its associated energy was moving further to the north, taking a route from the Four Corners toward western Kansas.  While we received about five-six inches of snow and the predicted polar air in Metro Denver, the winds from Walda have been from the north, negating much of the upslope effect; the latter is most potent for Denver when the winds arrive from the northeast.  In the end, most of the snow has fallen across Wyoming and South Dakota and blizzard conditions have been limited to the High Plains (where they are common during almost any snowstorm).

Except for the extreme cold air, Walda was fairly typical for April Front Range snowstorms and the media excitement over the past few days has proved to be a bit over the top.  On the other hand, in light of our ongoing drought, we could have used a record spring snowfall.

Monday, April 8, 2013

The Mt. Evans Massif

Mt. Evans, 14,264 feet, the prominent mountain WSW of Denver, is actually the high point and centerpiece of a dissected mountain ridge that stretches north to south between the Clear Creek and North Fork Valleys.  This massif is connected to the Continental Divide by a high alpine ridge to its west, crossed by the Guanella Pass Road; the latter connects Georgetown, on I-70, with Grant, on US 285, and may be inaccessible in winter or after heavy snowstorms (Guanella Pass has an elevation of 11,669 feet).

Most of the Mt. Evans massif is protected within the Mt. Evans Wilderness Area.  During the summer months, the central peak and its fascinating alpine ecosystem can be accessed with the family car by taking Colorado 103 south and upward from Idaho Springs (on I-70) and then switching to the Mt. Evans Highway (Colorado 5), a toll road, at Echo Lake.  More adventurous visitors can hike into the wilderness from a large number of trailheads; the most popular begin at the Mt. Evans State Wildlife Area, west of Evergreen, at the Deer Creek Trailhead, off US 285 via Park County Road 43, and from the Guanella Pass Road, especially south of the pass in the Geneva Creek Valley.

Bear Creek and its web of tributaries drain the east face of the Mt. Evans massif, creeks along its north and northwest edge drop into the Clear Creek Valley and tributaries of the North Fork of the South Platte drain the south and southwest slopes.  Since the entire massif lies east of the Continental Divide, all of its streams eventually lead to the South Platte River and thence to the Platte, Missouri and Mississippi Rivers.

Sunday, April 7, 2013

Front Range Cormorants

Double-crested cormorants have returned to Front Range lakes and reservoirs over the past week, among the earliest summer residents to arrive from their wintering grounds.  These large, dark-colored, aquatic birds may be seen alone when fishing but are generally encountered in flocks, especially at their roost and nesting sites.

Indeed, this most common and widespread cormorant in North America nests in colonies, usually placing their bulky nests in a grove of trees but sometimes directly on the ground.  They prefer islands or narrow peninsulas along lakes where, over the years, their copious guano kills the trees; once this occurs, the flock will choose another site or simply nest on the ground.  Feeding primarily on fish, cormorants are superb divers, equipped with heavy bones and reduced oil on their feathers; due to the latter trait, their plumage gets wet and they often perch on logs, islands, tree limbs or man-made structures with their wings spread to dry.

The interior population of double-crested cormorants has increased dramatically over the past half century, partly due to the large number of reservoirs that now dot the Midwest and Great Plains.  Those that summer along the South Platte Valley winter in Texas or eastern Mexico; arriving in late March or early April, they will depart for southern climes by mid November.  If conditions remain mild and open water is available, a small number may stay in Colorado for the winter months.

Saturday, April 6, 2013

The Nature of Coaching

Regardless of the sport, a successful coach is characterized by two essential traits.  The first is the knowledge to teach the fundamental skills and strategies that will lead to effective competition.  The second is the ability to prepare his or her players both physically and mentally for the challenges of their contest; the latter includes their vital role of instilling confidence in those they coach.

The abusive coaching tactics uncovered at Rutgers University were thus both inappropriate and counterproductive, a fact evident in that coach's won-loss record.  Unfortunately, as occurred at Penn State, administrators were reluctant to intervene, devoted more to the reputation of their institution and to the financial windfall of major sports than to the victims of abusive behavior; in both cases, this misguided approach magnified their losses.  Of course, if the abusive coaching behavior had been associated with a minor, non-lucrative sport, the coach would have been fired long ago with little fanfare on campus or in the media.

As the Final Four gets underway in Atlanta, all of the teams have the talent and skills to be victorious.  It is likely that the championship will hinge primarily on which coach was best able to motivate and instill confidence in his squad.

Friday, April 5, 2013

The Hartville Uplift

Wyoming is a spectacular landscape of mountain ranges separated by broad basins.  While most of the uplifts, including the Laramie, Medicine Bow, Wind River, Owl Creek, Bighorn, Absaroka and Teton Ranges, are well known to travelers, skiers, hikers and naturalists, a less obvious geologic uplift stretches across eastern Wyoming.

Known as the Hartville Uplift, this geologic arch connects the Laramie Range with the southwestern edge of the Black Hills, in South Dakota.  Separating the structural Powder River Basin, to its north, from the Denver Basin, to its south, this subsurface ridge of Precambrian basement rock formed during the Laramide Orogeny, some 65 million years ago, when the Rocky Mountains crumpled skyward.  Paleozoic and Mesozoic sediments lying above the arch were lifted as well, producing a broad ridge which has since been dissected by streams and buried by erosional debris from the mountains.

Today, evidence of the Hartville Uplift is provided by outcrops of Pennsylvanian and Permian strata amidst a sea of Cretaceous and Tertiary deposits.  The Uplift branches from the Laramie Range in the vicinity of Glendo Reservoir (on the North Platte River) and angles to the northeast where it eventually merges with the Black Hills.  Wyoming 270, between US 26 and US 20, is known as the Hartville Highway and runs through a large portion of the Hartville Uplift.

Thursday, April 4, 2013

Plant Behavior

Last evening, an episode of Nature on PBS purported to demonstrate that plants, like animals, exhibit behavior.  A range of examples included chemical communication between plants, chemical signaling between plants and their pollinators, chemical defenses used by plants, competition between plants for nutrients, sunlight and space, the symbiotic relationship between fungi and plants and the sharing of nutrients between various plants within an ecosystem.

For students of biology, the show was interesting but none of the data was surprising or  game-changing.  Whether plants manifest behavior depends on how we define that trait.  In many ways, plants communicate and compete at a level that compares with lower forms of animal life; though immobile, plants manage to locate food, defend themselves from predators, communicate stress and cooperate with other plants.  In neither case (plant or lower animal) are these forms of "behavior" conscious; rather, they demonstrate reflexive chemical mechanisms (including chemical driven growth patterns) that have evolved over the eons.  Since plants, unlike animals, do not possess a nervous system, it is not fully understood how "plant behavior" is coordinated; on the other hand, there is a great deal of chemical signaling in animals (including humans) that does not involve the nervous system (hormones, for example, are delivered through the bloodstream).

In reality, all life forms, from bacteria to plants to humans, are the product of their genes, which determine the structure and functional capabilities of that organism.  In that sense, plants are no different from animals and one might choose to view many of their chemical-induced physiologic functions as behaviors.  Indeed, were it not for our own neuroanatomy and chemical messengers, we could neither contemplate nor debate this issue.

Wednesday, April 3, 2013

An Upslope Stream

For the past 24 hours, cool air, low clouds and light drizzle have enveloped Metro Denver.  These classic upslope conditions have resulted from cold high pressure to our northeast and an upper level low over the Southern Plains.

The latter has been pumping Gulf moisture northward and its counterclockwise winds have been directing this flow northwestward across the Great Plains.  In concert, a high pressure dome over southern Canada and the Dakotas has blocked the moisture flow into that region and its outer clockwise winds have been pushing it toward the Front Range.  As this atmospheric stream was forced to rise by the terrain of the High Plains and Rocky Mountains, it cooled further and condensed, producing the low clouds and steady drizzle in Denver and light snow in the foothills west of the city.

Consulting the radar, one could see this rather narrow band of moisture, moving northward across Oklahoma City and Wichita and then making a broad curve across central Kansas, southwestern Nebraska and northeastern Colorado before ending in Metro Denver.  This morning, as the high pressure dome and upper level low push off to the east, the upslope flow is breaking down and pockets of blue sky are opening above the city.  By this afternoon, sunshine and mild air will return to the Front Range urban corridor.

Tuesday, April 2, 2013

The Adaptable Bobcat

Native to North America, the bobcat evolved during the Pleistocene Ice Age and ranges from southern Canada to central Mexico; though extirpated from some regions of the U.S., they have since recolonized most States, adapting to human presence and to a wide variety of habitat.  The most abundant and widespread wild feline on our Continent, bobcats are found from forested areas to grasslands and deserts but prefer wooded areas with rock outcrops in which to den.

Solitary for most of their life, which averages 6-8 years in the wild, bobcats are highly territorial.  Their diet consists primarily of rabbits and hares but may include mice, game birds, squirrels, skunks, fox and small deer; they may also consume insects, amphibians and reptiles and are known to attack small livestock on occasion.  Mating generally occurs in late winter and the kittens (usually 2-4) are born in mid spring; as with most mammals (including some humans), the father is not involved with the young once fertilization occurs.  By winter, the kittens generally leave their mother to establish territories of their own; some females may mate the following spring but males are not sexually mature until their second winter.  Though unusual, female bobcats are known to produce a second litter in late summer.

While their larger cousins, the lynx, are highly specialized with regard to habitat and diet, thus making them prone to dramatic population fluctuations, the adaptable bobcat has thrived in a wide variety of habitats and may even be encountered in suburban areas.  Most active near dawn and dusk, they are twice the size of an average house cat and are best identified by their tufted ears, long, striped legs, spotted coat and short, barred tail; variation in size and coat coloration occurs throughout North America, leading some taxonomists to recognize at least a dozen subspecies.

Monday, April 1, 2013

The Nature of Influence

From the moment of our birth, we are influenced by other humans.  During our first few years, that influence comes primarily from family and caretakers but, as we age, friends, teachers, cohorts, supervisors, advertisers, lovers, spouses, writers, speakers, mentors and, in some cases, strangers have a significant impact on our personal philosophy and behavior.

The tools of influence are highly varied but generally fall into the categories of reason, modeled behavior, reward and punishment.  Young children learn by mimicking their parents and siblings and readily respond to any praise that they receive.  By their teen years, reasoned discussion becomes much more important; if mutual trust, honesty and respect are part of the equation, influence is maintained.  By contrast, attempts to exert influence via threats or by imposing personal, unsubstantiated dogma are unlikely to be effective and will diminish one's opportunity to influence behavior.  Education broadens our exposure to factual information, ideas and the views of others, thereby making us less susceptible to the influence of zealotry or mysticism.

The concept of reward is effectively used by advertisers and, in the context of reasoned discussion, is an important element of influence, especially as it pertains to the benefits of commitment, hard work, perseverance and good citizenship; role models, including parents, colleagues, mentors and other admired persons, illustrate the rewards that stand to be achieved.  Conversely, the use of fear, guilt or threats to exert influence, while temporarily effective in some cases, is destined to fail; in addition to the negative recoil that is produced, reason, education and experience eventually erase the power of fear.