Showing posts from March, 2014

Noah & Natural History

Like Cecil B. DeMille's past epics, the new film, Noah, brings a Bible story to the big screen.  Initial reviews praise its special effects but, as one might expect, the Hollywood version is controversial, not strictly in line with the biblical plot.

Unfortunately, such films lend credence to the historical value of Scripture, placing its narrative on a par with the scientific investigation of natural history.  Those who favor the literal interpretation of ancient scripture and accept the doctrine of creationism will criticize the film for its artistic license while  biologists, geologists and anthropologists will recognize it as just another product of man's potent imagination.  Many of us are inclined to ask if South American tapirs, polar bears, giant pandas, Emperor penguins and other non-natives of the Middle East were in the arc.  Others might question whether human cultures on other Continents were wiped out by the flood; after all, they had dispersed to those regions l…

Formula for a Landslide

The landslide tragedy in Oso, Washington, occurred in a region of North America that is especially prone to such events.  Landslides generally occur in areas where porous, poorly-compacted sediments, lying on steep slopes, are subjected to a period of heavy precipitation.

Across the Pacific Northwest,  Late Tertiary and Pleistocene volcanic debris and glacial till are spread across older ranges of the Cascades and, as most of us know, that region is subject to episodes of copious rain and snow, courtesy of the Pineapple Express and other Pacific storm systems.  In most other parts of our Continent, loose volcanic and glacial sediments were deposited across relatively flat terrain or are not in the path of moisture laden storm systems; exceptions might include mountainous sections of the Northeast and hilly terrain near the Great Lakes.

While we cannot change the geology or topography of our regional landscapes, we can choose to avoid constructing homes and industrial plants in areas p…

The Nature of Hail

While we dodged tornados in Columbia yesterday, we did experience strong thunderstorms, one of which dropped penny-sized hail.  Fortunately, no damage occurred and the heavy rains were welcome following a relatively dry March.

Hail forms in thunderstorms that have an intense updraft, drawing warm, humid air into subfreezing layers of the atmosphere.  When super-cooled water droplets encounter ice crystals or specks of dust, they immediately freeze around that core; further movement up or across the thunderhead leads to additional coatings of ice as the small globe collides with other droplets of super-cooled water or with more ice crystals.  Once the hail fragments are too heavy to be kept aloft by the thunderstorm updraft, they fall to earth; these hailstorms may result in massive destruction of trees, crops, vehicles and man-made structures (especially if the hail has a diameter of 1 inch or more).  Thunderstorms generally produce hail with a diameter of 0.25 to 6 inches; the curren…

Tornado Season

Most of Missouri is under a tornado watch today.  As a Pacific storm approaches from the Southern Plains, it is pumping warm air and Gulf moisture into the Heartland, producing atmospheric instability. Combined with lift from the storm itself, these conditions are expected to ignite thunderstorms this afternoon which, interacting with a potent jet stream, may become tornadic.

While tornadoes may occur along the Gulf Coast region throughout much of the year, they are most common in the American Heartland from April through June; though it was a quiet March for tornadoes in the Deep South (primarily due to the extreme winter conditions), the season appears to be getting underway a bit early in the Midwest, where their incidence generally peaks in May.  Of course, an early outbreak has no implications for the rest of the spring but this winter's fickle jet stream may forebode an active season.

Short of severe weather, the mild, humid air is a refreshing change from the frigid incursi…

Formation of the Indian Ocean

About 200 million years ago (MYA), the Tethys Sea split Pangea into Laurasia (the northern continents) and Gondwanaland (the southern continents); the latter included Africa, India, Antarctica, South America and Australia.  Since that time, the Indian Ocean has formed as these Southern Continents split from one another.

In the mid Jurassic Period, 150 MYA, the Atlantic Ocean began to form, splitting Europe from North America and Africa from South America.  By the early Cretaceous Period, some 130 MYA, a landmass including Madagascar, the Seychelle Islands and India rifted from the rest of Gondwanaland and, by 100 MYA, Africa split from Antarctica as the Southwest Indian Ridge began to form.  About 85 MYA, India rifted from the Madagascar-Seychelles land mass and Australia began to split from Antarctica along the Southeast Indian Ridge.  Finally, the Mid Indian Ridge (which trends NNW to SSE and connects the Southwest and Southeast Indian Ridges) began spreading as well, accelerating I…

The Phoebe's Leap of Faith

Yesterday, on a cloudy and chilly day in Columbia, an eastern phoebe foraged across the restored prairie at Forum Nature Preserve.  Among the earliest of our summer birds to arrive from the south, these flycatchers seem to accept the risk that an early spring freeze may wipe out their prey; fortunately, they are able to survive on berries and soft seeds for limited periods of time.

We humans admire the hardiness and "faith" of this early migrant, perhaps swayed by the promise of spring that he represents.  Of course, the eastern phoebe neither anticipates problems nor pretends to display courage.  Even though some of his cohorts may succumb to late winter storms, he travels northward in response to instinct, set in motion by the lengthening daylight.  He has no capacity for fear and places no faith in the cooperation of Mother Nature; she, in turn, is not sentimental and the phoebe's survival will depend solely on luck and his own skill and adaptability.

It is reasonable…

Teal Days

As the tide of spring gains momentum, blue-winged teal have returned to Eagle Bluffs Conservation Area, on the Missouri River floodplain.  Large flocks of these attractive ducks now mingle with the numerous mallards, shovelers and coot, joining smaller numbers of other waterfowl species; on my visit this morning, these included pintails, gadwalls, green-winged teal, American wigeon, lesser scaup, buffleheads and common mergansers.  A flock of greater white-fronted geese still graced the refuge, pied-billed grebes dove in the shallows and several flocks of American white pelicans moved among the deeper pools.

In addition to the teal, other signs of our accelerating spring included squadrons of tree swallows, a massive congregation of killdeer and small flocks of long-billed dowitchers and pectoral sandpipers; a solitary yellowleg was also observed.  But it was the invasion of blue-winged teal, having spent their winter along the Gulf Coast, that was the highlight of my visit, signaling…

A Delayed Chorus

Though another chilly air mass has dropped into the American Heartland, the loud, rising calls of upland chorus frogs echoed across the Garth Wetlands, in northern Columbia, this afternoon.  Resembling the sound of a thumbnail running along a plastic comb, the call of these tiny tree frogs is generally heard by late February; this year, due to our long, frigid winter, their chorus was delayed by several weeks.

Joining the distinctive din of the chorus frogs were the high-pitched notes of spring peepers and the duck-like chortle of leopard frogs.  The usual mix of permanent and winter songbirds sang from the adjacent woodlands, their tunes more intense in the high March sun, and an armada of aquatic turtles basked on a muddy bank.

The highlight of my afternoon visit, however, was the presence of a long-billed "sandpiper" that snoozed at the edge of a marsh.  Its striped crown and back identified it as a common snipe, likely en route to more northern breeding grounds.  Snipe m…

Cancer & Human History

Whenever a science-related segment appears on the evening news, it immediately grabs my attention.  Unfortunately, unless it appears on PBS, I am generally disappointed by both the coverage and its simplistic conclusions.  After all, one can't adequately present a complex subject in two minutes or less.

This past week, one of the network news programs included a brief segment on the discovery of apparent lytic bone lesions in a skeleton dating from 3000 years ago; they reported that it is the earliest evidence of cancer in a human being and concluded that the disease has tormented our species for at least 3000 years.  Of course, they didn't have time to place that discovery in perspective.  Humans had walked the Earth for about 127,000 years before that individual died with either primary or metastatic bone cancer; surely, hundreds of thousands (if not millions) of cases preceded that person's illness.  Neither did they have time to emphasize that "cancer" is a s…

The Nature of Obsession

When tragedies occur, as with the recent disappearance of Malaysian Flight 370, the cable news networks take advantage of our obsession with the event.  Providing 24/7 coverage, they keep us glued to our televisions or mobile devices as we seek every possible fact, whether or not we've heard them a dozen times before.

Obsessions stem from fear or anxiety such as the fear of random death or anxiety stemming from our own sense of vulnerability or inadequacy.  By focusing intently on an event or on a facet of our life, we strive to reassure ourself that there is a logical explanation for what has happened or that we have the capacity to deal with whatever is causing our stress.  In the latter case, we may or may not be consciously aware of the source of our obsession and psychotherapy may be necessary to uncover the cause and effectively address the problem.

While temporary obsession with a tragic event is common among humans, persistent obsessions that disrupt our life (and the live…

South with the Upslope

Yesterday morning, as a cold, north wind raked the Front Range urban corridor, sweeping snow flurries across Metro Denver, I headed south, climbing through the Plum Creek Valley toward the Palmer Divide.  Once I reached the elevation that supports ponderosa pine woodlands (about 7000 feet), I pulled off along a scenic, tree-lined meadow, backed by the Front Range foothills.

The meadow grass rippled in the strong wind as waves of low clouds and fog drifted in from the north, unleashing swirls of snow as they pushed into the foothill canyons.  Between these swaths of precipitation, bright sunshine lit the scene, belying the chilly air; during one of those sunny interludes, a golden eagle circled overhead and a flock of mountain bluebirds, just back from the Southern Plains, worked their way across the meadow.

Before I left my lofty perch, the snow intensified, dusting the pines and grassland, and upslope fog enveloped the valley.  Then, as I descended toward Denver, I dropped below that…

Cranes on the Platte River

One of the greatest birding spectacles in North America and, indeed, on the planet, is the staging of up to 600,000 sandhill cranes along the Platte River in early spring.  Congregating along an 80 mile stretch of the river, the cranes begin to arrive in mid February and move on by mid April; peak numbers generally occur in late March.

Having wintered in Texas, New Mexico, Arizona and Mexico, the mid-Continental population of sandhill cranes funnels through south-central Nebraska, on their way to breeding grounds from northern Canada to Siberia.  The great majority stop to rest and feed in the Platte River Valley, gathering on sandbars at night and dispersing to wet meadows and cornfields during the day.  Joining the cranes are bald eagles and migrant flocks of waterfowl and the annual spectacle attracts some 70,000 human visitors from across the globe.

The Audubon National Crane Festival, established in 1971, is held in Kearney, Nebraska; this year, it will run from March 20-23.  Tho…

Birding from a Barn Roof

Granted a summer-like day in the middle of March, I could find no excuse to avoid repairing our barn roof, damaged by a recent wind storm.  Besides, as is common along the Front Range in March, it's expected to snow tomorrow.

As a long-time birder, I cannot help but notice the varied calls of our avian neighbors whenever I work outside; today was no exception.  While the hysterical call of flickers dominated the background, noisy squadrons of Canada geese vied for attention and the raucous cries of blue jays, not yet assuming their musical tone of spring, echoed across the farm.  In nearby trees, the distinctive chatter of bushtits and chickadees could be heard, a lone downy tapped along a dead limb and our resident pair of collared doves flew in to inspect my work.  Of course, I stopped now and then to scan the clear blue sky, finding a pair of redtails riding the warm breeze and an occasional flock of mallards racing across the South Platte Valley.

Yes, birdwatching has many rew…

Faith, Hope & Charity

Faith, hope and charity are three human "virtues" that are often mentioned in tandem, implying that they are interconnected.  While they are all elements of human nature, I would argue that they they are distinct products of our intelligence and personal experience.

Faith, in essence, is the belief in something that we have not yet seen or experienced.  Aligned with trust, it may be faith in a deity or faith in another human being; in either case, this trust is modified by what we know, by what we don't know and by the influence of other trusted individuals in our lives.  Hope is a measure of our future expectations, generally based on our past experience.  Some are inclined to define it as one's degree of optimism while others view hope as nothing more than wishful thinking; again, such disparity reflects events that have already molded our lives.

In contrast to the intellectual, abstract nature of faith and hope, charity is an open choice to share our good fortune …

Cooper's Hawk Upstages Ducks

On this morning's monthly waterfowl count, the last of the winter season at South Platte Park, ducks were represented by a fair number of species but, at least for our group, were modest in number.  Along our stretch of the river, mallards and buffleheads were most numerous, followed by gadwalls, common goldeneyes, northern shovelers, coot, green-winged teal and a pair of ruddy ducks.  The highlight of the morning proved to be a Cooper's hawk, perched in a dense, riverside woodland.

Permanent residents throughout the contiguous United States, Cooper's hawks are summer residents across southern Canada and winter visitors in Mexico and Central America.  Come spring, the male, which is smaller than his partner, builds the nest and then catches prey for the female and the nestlings until the young are ready to fledge.  Like other accipiters, Cooper's hawks are designed for rapid, agile flight, zig-zagging through forest or open woodlands to snare a variety of songbirds and…

Birding Hotspots near Denver

Denver is one of the best birding destinations in North America.  Within a 40 mile span, east to west, one can explore five life zones, with elevations ranging from 5000 to 14,250 feet.  Novice birders and those visiting the area want to know where to go to find a wide variety of western species. The following recommendations are based on my experience over the last thirty years; the bird lists are neither complete nor grouped by season.  Regardless of where you go, birding is always most productive during the morning and late daylight hours; warm season visits to higher elevations should be planned before early afternoon, when dangerous thunderstorms often develop.

To find birds of the Colorado Piedmont, I recommend Chatfield State Park, southwest of Denver, Barr Lake State Park, northeast of Denver and Sawhill Ponds Nature Preserve, east of Boulder; these areas are excellent sites to observe American white pelicans, Swainson's hawks, cinnamon teal, western grebes and migrant wat…

The Watersheds of Texas

The State of Texas, stretching from the Southern Plains and the Desert Southwest to the Gulf of Mexico, is drained by numerous streams and rivers which comprise thirteen major watersheds.  The Canadian River flows across the north section of the Northern Panhandle (eventually merging with the Arkansas River in Oklahoma) while the Red River watershed drains the Panhandle's southern section and a narrow strip along the border with Oklahoma and Arkansas.

South of the Red River watershed, a series of parallel watersheds are aligned from northeastern to southwestern Texas, all flowing southeastward toward the Gulf of Mexico.  From northeast to southwest, the primary watersheds are the Sabine, the Trinity (including Metro Dallas), the Brazos (including Lubbock), the Colorado (including Austin) and the Pecos-Rio Grande Rivers.  Close to the Gulf are shorter watersheds, also flowing southeastward to the sea; the Nueces, San Antonio, Guadelupe and Lavaca watersheds are aligned southwest to…

Thoughts on Assisted Suicide

Many Americans have "living wills" which, in most cases, limit aggressive care should their chance for a meaningful recovery be deemed hopeless.  Many others, facing physical or mental deterioration due to advanced age or chronic illness, place limits on their medical care, declining cardiopulmonary resuscitation, intubation, ventilator support, feeding tubes or other measures.  Finally, the rise of palliative care and hospice services has significantly reduced suffering for those in the final days, weeks or months of their life.

Some physicians, myself included, feel that another option should be available to those losing their independence due to a medical condition for which effective therapy does not exist.  While assisted suicide is legal in some countries and in the States of Oregon, Washington and Vermont, this humane intervention is officially illegal throughout most of the U.S; even the progressive States permit assisted suicide only if the patient is expected to di…

A Summer Drive in March

Returning to Colorado today, I left Columbia just before dawn.  A steady south wind was sweeping warm air into the Heartland and high temperatures were expected to reach 70 degrees F along the entire course of my journey.

Taking advantage of the south wind, numerous flocks of snow geese and greater white fronted geese were encountered across western Missouri and eastern Kansas, heading north to their next rest stop.  By the time I reached central Kansas, the geese were no longer observed but several flocks of American white pelicans circled northward, their white plumage reflecting the intense mid-day sun.  When I pulled into our Littleton, Colorado, farm, the sun was setting but the local temperature was still 68 degrees F.

Outbreaks of excessive warmth during the colder months generally develop ahead of cold fronts and such was the case today.  A band of clouds along the Front Range confirmed the presence of an approaching storm system, which will keep Metro Denver's temperature…

To Spook an Owl

This morning, after hiking across a ridgetop meadow south of Columbia, I decided to return to my pickup along a valley trail which cuts through a creekside woodland.  Soon after entering that grove of trees, I startled a large raptor that flew further into the woods; its bulky frame and silent flight indicated that it was an owl.

Sure enough, as I rounded the next curve, I found myself staring into the dark eyes of an adult barred owl, perched above the trail.  After tolerating my presence for a minute or so, he flew deeper into the trees and I continued my hike, glad to have encountered that night hunter in the light of day.

Of course, it is not unusual to observe barred owls during the day, especially in early to mid spring when their breeding season is underway; indeed, their questioning call is often heard in March and April, day or night.  Best observed in riparian forest or wooded marshlands, barred owls are nocturnal hunters, feasting primarily on mice but also consuming songbi…

The Gobi Desert

The Gobi Desert, covering more than 500,000 square miles, is the largest desert in Asia.  This vast and varied ecosystem stretches across southern Mongolia and northwestern China; it is bounded by the Tibetan Plateau to the southwest, the Altai Mountains to the northwest, the Mongolian steppes to the north, the Yin Mountains to the ESE and the Yellow River Valley to the southeast.  Known for its extreme temperature ranges from summer to winter and throughout any given day, this high, northern desert sits on a plateau with elevations of 3000 to 5000 feet; its desert ranges add another 1000 to 2000 feet of elevation.

While images of the Gobi often display towering sand dunes, most of the desert is covered by bleak gravel plains, rocky badlands and sparse grasslands, broken by widely scattered oases harboring shrubs and desert trees.  Native wildlife includes bactrian camels, black-tailed gazelles, a dwindling population of Gobi bears, the Asiatic wild ass and jerboas. Though important t…

Dietary Habits: Food for Thought

The human diet varies dramatically across the globe and, in developed countries, has changed over the years.  As one who grew up in the American Midwest during the middle of the 20th Century, I consumed a "meat and potatoes" diet; vegetables, when served, came in a can and fruit consumption was primarily limited to orange juice, apples and grapes.  I was in college before I ate my first salad.

Most humans have had similar experiences; diets correlate with one's cultural background and, like many deep-seated beliefs, go unchallenged until that individual is exposed to persons from other regions of the country or the globe.  Indeed, many of us first experience this disruption when we become engaged or married and must confront food that is "foreign" to our taste.

Of most significance is the fact that dietary habits are established in childhood; depending on one's cultural background, such habits may be healthy or unhealthy and, once ingrained, they may be dif…

A Welcome Mourning

Over the past week, the melancholy song of mourning doves has wafted through our neighborhood.  While mild weather has finally enveloped mid Missouri in the last few days, the singing began well before the latest outbreak of Arctic air departed the region; indeed, these doves are responding to the prolonged daylight, not the warmer temperatures.

Among the earliest birds to nest in the American Heartland, mourning doves will fledge their first brood by mid spring and will produce at least one more clutch of eggs before the summer ends.  Their mellow tune, always welcome after a long, cold winter, will be heard throughout the warmer months but the doves generally fall silent by early autumn.  Permanent residents in Missouri, these sociable birds usually gather in large flocks from late summer through winter, roaming fields and farmlands to feast on seeds and waste grain.

Though most nest in trees, some mourning doves use the ledges or sills of houses and barns.  Once fledged, the patien…

Duck Clouds at Eagle Bluffs

As the tide of spring begins to accelerate, the number and variety of waterfowl at Eagle Bluffs Conservation Area, on the Missouri River floodplain, is dramatically increasing.  This morning, massive clouds of ducks filled the air while even larger flocks gathered on the fields, lakes, ponds and sloughs.

Mallards and northern pintails accounted for at least 90% of the duck population, joined by smaller numbers of American wigeon, gadwalls, northern shovelers, American coot, buffleheads, ring-necked ducks and common and hooded mergansers.  As usual, Canada geese were present in large numbers now mingling with flocks of greater white-fronted geese; while a flock of snow geese passed overhead, none were observed on the ground (except for the remains of one hapless migrant, torn apart by an eagle or coyote).  Other sightings included seven sandhill cranes, numerous great blue herons, a half dozen bald eagles and a small flock of American white pelicans.

This morning's spectacle will o…

A Grassland in Early March

South of Columbia, Rock Bridge Memorial State Park harbors a large grassland, hemmed in by forest and broken by woods that surround marsh-lined ponds and sinkholes.  On this mild, breezy afternoon, I hiked its wide trail and, as I walked, I heard only the rustle of the dry grass and the occasional raucous cry of a blue jay or red-bellied woodpecker.

However, when I would stop to survey the scene, the chirps and rustle of sparrows could be heard in the dense grass and other open country birds were spotted among the trees and thickets.  Tree sparrows were especially common while the homesick tune of white-throated sparrows made that species more conspicuous; song, white-crowned and swamp sparrows were also encountered.  Chickadees, cardinals and yellow-rumped warblers foraged in the woodland groves while eastern bluebirds, northern mockingbirds, crows and American goldfinches roamed the open grassland.  Overhead, a pair of red-tailed hawks cavorted in the clear blue sky, their high pitc…

The Ugly Weeks

The first few weeks of March in the Temperate Zone of the Northern Hemisphere are generally less than pleasant.  Chilly waves of winter still drop in from the north while humid air flows up from the south.  This combination, stirred by Pacific storms that ride in from the west, leads to raw, cloudy days with cold rain or wet snow.

To make matters worse, this chilly precipitation falls on frozen soil, leading to muddy trails and backroads, swollen streams and widespread flooding.  While lawns may begin to green and flowering bulb plants add some color to the woodlands and flower beds, damp leaf litter and forest debris still coat much of the ground.  The trees and shrubs are, for the most part, leafless and their lack of transpiration only adds to the runoff that triggers mudslides and flooded landscapes.

Of course, this ugly, damp weather provides ideal feeding grounds for migrant waterfowl and shorebirds and fuels the tide of spring that will gain traction later in the month.  As the…

Return to Riverlands

Yesterday, a friend and fellow birder invited me to visit the Riverlands Preserve, north of St. Louis; he was hoping to find Thayer's and Iceland gulls that had recently been observed along the Mississippi.  Though our search for those gulls was in vain, we did encounter a fabulous diversity of birdlife.

On that sunny but cold and windy morning, at least thirty tundra swans were feeding in the riverside lakes, joined by American white pelicans and a wide variety of diving ducks; among the latter, common goldeneyes, common mergansers and hooded mergansers were most numerous but a solitary, male white-winged scoter proved to be the highlight of our visit.  Several flocks of greater white-fronted geese flew over the refuge or stopped to feed along the levees.  Surveying the lakes were more than fifty bald eagles while, out on the grasslands, northern harriers, American kestrels and red-tailed hawks hunted for their morning meals.  Other sightings included a pair of ruddy ducks, a few…