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Showing posts from March, 2008

Spring Reigns

More than a week after the equinox, spring has taken hold in central Missouri. Forsythias, red maples and wild cherries are blooming and the first crops of henbit, violets and dandelions are brightening the suburban lawns.

Down at the Forum Nature Area, the seasonal lakes have filled with rainwater and the duck-like chortle of leopard frogs has joined the background din of chorus frogs. Eastern bluebirds and tree swallows have paired off and are checking out the nest boxes while clouds of insects, a welcome sight to the phoebes, rise from the shallows.

This morning dawned warm and humid, with a southerly breeze and the threat of thunderstorms. Winter will surely throw a few more jabs our way but, by all accounts, spring has won the battle.

Swallows and Saints

Long before humans inhabited Southern California, cliff swallows returned each spring to nest on rocky bluffs along its streams and rivers. With the arrival of Spanish missionaries, artificial cliffs (mission buildings) began to appear in the rural countryside, offering ideal nest sites for the swallows. The Catholic priests and brothers at the San Juan Capistrano Mission, now in Orange County, observed the seasonal patterns of these birds and, attentive to their religious calendar, noted that they usually arrived on or about March 19, the feast of St. Joseph, and departed for the south on or about October 23, the feast of St. John (San Juan).

The "miraculous" attachment of these swallows to the Mission and their apparent adherence to the feast days eventually caught the attention of the Church, the community and the worldwide media. The fact that they migrated to thousands of other locations across the Continent, arriving and departing on a similar schedule, was apparentl…

Caribbean Subduction Zones

The breakup of Pangea began with the formation of the Tethys Sea during the Triassic and continued with the opening of the Atlantic during the Jurassic. The latter began about 150 million years ago and continues today, pushing the North and South American Plates to the west. The Caribbean Plate, once part of the Pacific, wedged between the two American Plates as they moved westward and began to override them.

Along the eastern edge of the Caribbean Plate, the American Plates are subducting; as these plate margins are forced downward toward the Earth's mantle, they begin to melt, producing volcanism to the west of the subduction zone. This has led to a volcanic island arc (part of the Lesser Antilles), from the Virgin Islands on the north to Grenada on the south; today, 17 active volcanoes dot this island chain. Mt. Pelee, on Martinique, erupted in 1902, killing more than 30,000 people; most recently, the Soufriere Hills Volcano, on Montserrat, has been erupting intermittently s…

Waves of Thunder

Late yesterday afternoon, a cold front draped across central Missouri, from west to east. As a result, a thick cloud layer formed above Columbia, producing a cold drizzle. Though no lightening or dark skies were visible, waves of thunder rumbled overhead, waxing and waning like the surf on a beach. Checking the local radar, I found that the thunder was originating in large storms to our north and south.

Thunder begins as a shock wave, produced as lightening explodes through the atmosphere. As it propagates outward, the high-frequency sound waves begin to dissipate while the low-pitched sound persists. Nearby cloud-to- ground lightening produces a sharp clap of thunder while thunder from distant storms arrives as a low rumble; in cases where the storm is very distant, the sound wave frequency may be too low for the human ear to detect. Since lightening often develops in a branching pattern (especially in cloud-to-cloud strikes), the sound from its various segments, crossing varied…

Anticipation

March and April can be difficult months in the American Midwest. Periods of warm, sunny weather induce spring fever, only to be doused by the next Alberta Clipper or Pacific Front. Cool, cloudy intervals put thoughts of May on hold and a late snow or killing freeze can annihilate what little progress has occurred. Those with apricot or peach trees (early blooming fruits) are especially keen to these fickle weather cycles.

Unlike wildlife, man is burdened with the capacity for anticipation. We know that warm days and balmy nights lie ahead and often resent the setbacks that nature throws our way. Wild creatures, on the other hand, are content to take one day at a time, governed by instinct and the lengthening daylight. They sense what they must do today, not what awaits them tomorrow. Patience and perseverance are their natural virtues and we would do well to absorb those traits.

A Spring-Fall Mix

It was mild in Columbia last evening, with temperatures in the upper fifties. But the dry air and east breeze made it feel more like early October than late March. Adding to this illusion, a hint of wood smoke was in the air and the squeaky sound of a squirrel gnawing on a walnut husk echoed through the yard. Even the call of a white-breasted nuthatch, though heard year-round, was more reminiscent of fall.

There was little to suggest that spring would soon unfold. The trees and shrubs remain leafless and the greening of the lawn is well behind schedule this year. Turkey vultures drifted through the evening sky but the chimney swifts won't appear for several weeks; the only birdsong was provided by our permanent or winter residents.

But the magnolia buds are swelling, daffodils are blooming and the hysterical call of the flicker rings through the neighborhood. April and the verdant season will soon arrive!

Meeting Stan Freden

In 1980, as we returned from a ski trip to Utah, my wife and I were bumped from our flight and placed on another. Advised to grab any open seats, we settled next to a middle-aged gentleman who occupied my cherished window spot. Taking off from Salt Lake City, I noticed that he was studying the landscape below and I commented on the spectacular scenery, pointing out the High Uintas to our north. His amiable rapport led me into a dissertation on my conviction that air travel is the perfect way to learn geography and that videos, shot from aircraft, should be used in the classroom.

After patiently listening to my bold remarks, he asked me if I had heard of the Landsat Program (I had) and went on to inform me that he was a nuclear physicist who worked at NASA's Goddard Space Flight Center and was one of the authors of "Mission to Earth, Landsat Views the World." Better yet, sensing my interest in geology and geography, he offered to send me a copy; it has been a cherished…

The Early Flycatcher

Despite the cold, gray, breezy weather, a scattered flock of eastern phoebes turned up at the Forum Nature Area, in Columbia, yesterday. These common, summer flycatchers look like miniature eastern kingbirds and are easily identified by their habit of pumping and spreading their tail after landing on a perch. Best found along the wooded edge of streams and wetlands, they feed primarily on flying insects but, at this time of year, usually settle for larvae, seeds and ground-dwelling invertebrates.

Eastern phoebes are among the first "summer birds" to arrive in the spring, often turning up by mid March. Why they take their chances with the fickle Midwestern weather is a mystery and some undoubtedly succumb to heavy snow, severe cold or ice storms. Those that survive will build nests of mud and straw, which they place beneath rock ledges, eaves, bridges or barn roofs. One must admire their pioneering spirit!

Immortality

Ever since hominids developed the intellectual capacity to fear death, we have sought the key to immortality. Neanderthals were the first of our Genus to bury their dead and early human cultures used rituals and burial artifacts to ensure a safe journey into the afterlife. Even today, many humans are interred with their prized possessions and Churches lure members with the promise of immortality. Focused on the afterlife, religious zealots often fail to experience the many joys of their earthly existence and, in some cases, are willing to martyr themselves (and destroy the lives of others) in pursuit of their spiritual goals.

On this Christian feast of the Resurrection, it is safe to say that science cannot prove nor disprove the existence of an afterlife. On the other hand, we can achieve immortality in ways that all of us have experienced: by passing along our genes, our knowledge, our philosophy, our advice and our love. We will live on in the memories of those we have touched …

A Watershed Journey

Naturalists tend to ignore State and National borders, preferring to view our planet as a mosaic of geophysical provinces. Most of these regions are large and extend across man's artificial boundaries; the Rocky Mountain Province, for example, stretches through Canada, the U.S. and Mexico.

Another way to view the landscape is through its pattern of watersheds. The largest rivers have watersheds that often cover parts of several geophysical provinces; for example, the Missouri River drains part of the Rocky Mountain, High Plains, Central Lowlands and Ozark Highlands Provinces. By dividing these major watersheds into their secondary components, one gains a better appreciation for the complexity of regional topography; if nothing else, watching for these natural boundaries can make your travels more interesting.

Driving from Colorado to Missouri, today, I crossed only two State lines but passed through a series of watersheds. East of Denver, I-70 remains within the South Platte wat…

After the Thaw

Another mild and sunny morning sent me down to the South Platte Valley for a hike along the river. The recent bouts of warm weather had opened the valley lakes and the river's winter concentration of waterfowl had clearly dispersed. Small groups of mallards, gadwall and green-winged teal still fed at the margins of the stream, joined by a lone pair of wood ducks; flocks of common mergansers, redheads and ring-necked ducks had moved to deeper waters and could be seen on a large lake just west of the river.

While the grass was greening beneath the cottonwoods, the trees and shrubs remained barren, giving the scene a winter look. On the other hand, the winter silence had given way to a motley choir of magpies, song sparrows, killdeer, kingfishers and flickers. Above it all, a red-tailed hawk cavorted in the early spring breeze and a trio of cormorants headed upstream, back from a winter in the south.

A day after the spring equinox, the South Platte Valley had taken on the feel of a…

White Ranch Park

One of my favorite destinations close to Denver is White Ranch Park, northwest of Golden. Draped across Belcher Hill and its adjacent ridges, this 3040 acre refuge, a former cattle ranch, includes all of the habitats that characterize the Front Range foothills: ponderosa parklands, spruce-fir forest, foothill meadows and rocky shrublands. The Park is a member of Jefferson County's fabulous Open Space system and is reached via Golden Gate Canyon (just north of Golden, off Colorado 93) and Crawford Gulch Road.

White Ranch, accessed by a fine network of trails, is renowned for its splendid views and for its diverse wildlife population; elevations range from 7000 to 7880 feet. Resident mammals include ground squirrels, Colorado chipmunks, Abert's squirrels, porcupine, fox, bobcats, coyotes, mule deer, black bear and mountain lions; elk also winter at the refuge. Bird life includes golden eagles, wild turkey, blue grouse, Cooper's hawks, Steller's jays, Townsend's so…

The Noisy Plover

Most North American shorebirds breed in the Arctic and winter on southern coasts; exceptions include species that summer in the U.S., such as spotted sandpipers, mountain plovers, upland sandpipers and long-billed curlews. But the most widespread and conspicuous inland shorebird is the killdeer.

Killdeer are robin-sized plovers that are easily recognized by their two black breast bands and loud, piercing call; in flight, their white wing bars and rusty tail feathers aid identification. They are often seen on mudflats along reservoirs and large rivers but also favor short grass areas such as lawns, grazed fields, airports and cemeteries. State Parks with lakes or reservoirs, offering both mudflats and mowed grasslands, are usually the best place to observe them.

Breeding throughout most of the lower forty-eight and southern Canada, killdeer nest on the ground, keeping predators at bay with their aggressive and noisy displays; should this behavior fail, they often resort to the "b…

Tibet and Appalachia

At first glance, the Tibet and Appalachian Plateaus appear to have nothing in common. The first is a high, stark, arid landscape while the latter is a heavily vegetated, humid swath of ridges and valleys. And while the Appalachian Plateau covers a large area, from Upstate New York to northern Alabama, the Tibet Plateau, the largest highland region in the history of our planet, is equal to half the area of the lower 48 States.

But from a natural history perspective, the two Plateaus were formed in a similar manner and may have looked much alike at different times in Earth's history. During the Permian Period, about 250 million years ago, the North American and African Plates collided as the megacontinent of Pangea formed. This collision forced up the Southern Appalachians and the adjacent Appalachian Plateau. Much later, about 55 million years ago, the Indian subcontinent began to collide with southern Asia, a process that continues today. This impact created the Himalayas and…

Front Range Snow

Metro Denver sits in the southwestern corner of a broad, topographic wedge that is bordered by the Front Range, to the west, and the highlands of the Palmer Divide ridge, to the south and southeast. Drained by the South Platte River and its tributaries, this wedge slopes gradually downward to the northeast.

Winds that blow into Denver from the West, South or Southeast descend from higher terrain; since air compresses, warms up and dries out as it descends, the bordering high country keeps the Metro Area dry and sunny much of the time. Then again, March is the snowiest month in Denver as Pacific storms track across the Southwestern States, pulling in moisture from the High Plains and forcing it to rise as it nears the Rockies; rising air cools and expands, triggering precipitation. For Metro Denver to receive significant snowfall, the storm must create a wind field that pulls moisture in from the northeast; storms that produce this scenario generally track along the Colorado-New Mexico …

High Plains Sandhills

On my trip back to Colorado, today, I observed a flock of migrating sandhill cranes in western Kansas. Heading for their staging grounds along the Platte River of central Nebraska, they were no doubt taking advantage of southeast winds ahead of the approaching Pacific storm.

After wintering in Mexico, Texas, and New Mexico, the cranes begin heading toward Nebraska in mid-late February, covering up to 500 miles a day. The Platte River Valley is their major staging area before moving on to Canada, Alaska and Siberia. Over half a million sandhills inhabit the Valley during the month of March, roosting in the River shallows and feeding on adjacent fields. Corn is their primary food but they also consume tubers, worms, insects and other invertebrates.

By the second week in April, most will depart for breeding grounds to the north. Lesser sandhill cranes, which make up 80% of the Platte River population, will summer in the Arctic, favoring the tundra of northernmost Canada, Alaska's …

Cold Rain

For those of us who enjoy the outdoors, cold rain is surely the least welcome weather. While we can dress for frigid days, maneuver through the snow with boots or skis and endure the summer rains with a simple parka, cold rains chill you to the bone and few humans choose to venture outside. Such is the weather today in mid Missouri, with intermittent rain and temperatures in the thirties.

Unlike modern humans, wild creatures have little choice but to carry on with their daily routines. Their food does not come packaged for indoor consumption! Our backyard feeder, offering high calorie food without the energy expenditure of foraging, is busier than normal. The usual songbirds are visiting and a mixed group of fox and gray squirrels are searching the ground for fallen seed. Downy wood-peckers, chickadees, nuthatches and a couple of Carolina wrens are working on the suet block, which will be targeted by starlings later in the day.

Of course, these creatures would do just fine without our h…

Surfing the Fronts

Just as surfers ride the edge of an oncoming wave, waterfowl move northward on southerly winds that precede an approaching front. Boosted by these winds, they follow major rivers from their wintering grounds to the prairie "pothole" wetlands of the Northern Plains and Canada.

Along their journey, these geese, ducks and coot stop to rest and feed on lakes, marshlands and flooded fields. The tide of the migrants peaks in mid to late March, coinciding with flood season across the Heartland, triggered by heavy rains and melting snow. It is thus a good time to visit local reservoirs and wetlands; plan to bring warm, waterproof clothing, binoculars and, if available, a spotting scope. In areas accessed by graveled roadways, using your car as a blind is especially effective when viewing waterfowl.

Diving ducks such as buffleheads, ring-necks, canvasbacks, redheads, goldeneyes, mergansers and scaup favor the deeper waters of lakes and reservoirs. Surface feeders, including malla…

Voyeurs of Pain

Religious people believe that man is inately good, instilled with God's divine spirit. I am inclined to believe that we are a product of our genes and our experience; the latter includes the influence of our families, our friends and our enemies alike.

One disturbing aspect of human culture is our fascination with suffering. Like the Romans and their Colisseum, modern societies exploit the misfortunes of others, offering entertainment that focuses on their pain. Cage fighting, "cop shows," reality series and the obsession with the dysfunctional lives of celebrities are just a few examples. Cable news websites invite you to "listen to the 911 call" or "watch as the parents plead for their son's life."

Whether man has a divinity that other animals lack is a matter of faith and speculation. All I know is that other creatures are not nearly as mean, vindictive and intolerant.

Seasonably Erratic

Through this second week in March, our average high was about 50 degrees F in central Missouri. While fairly normal for this time of year, that average included one day in the 70s and a couple in the 30s. Over the years, meteorologists develop all kinds of "averages" for any date but, in any given year, the variance may be dramatic.

For a month like March, it is purely academic to use phrases like "unseasonably warm" or "much colder than average." Typified by frequent Pacific fronts which move across the country every few days, March is a roller coaster of warm and cold periods. Ahead of each front, warm, humid air streams northward from the Gulf of Mexico while, behind the front, cold, Canadian air plunges into the Heartland. By late March, as the higher sun angle and more northerly jet stream begin to moderate these erratic swings, warmer temperatures prevail. As a consequence, storm systems associated with the fronts become more potent and we ente…

Life in Motion

Sitting on a park bench and reading a book on a calm, spring day, one might relish the peace and stillness. But they would be mistaken.

The bench and its patron are firmly held to the Earth which, itself, is rotating at 1000 miles per hour. At the same time, our planet is hurtling through space at 67,000 miles per hour, on its annual journey around the sun. Not to be out done, our home star is circling the center of the Milky Way Galaxy at 486,000 miles per hour, taking about 225 million years to complete its circuit.

Of course, we Earthlings are oblivious to all of this motion, tied to the planet by the force of gravity. Only the spring breeze, moving through our protective atmospheric envelope, hints at the natural forces that govern our lives.

The Mellow Bird

Most songbirds are nervous creatures, flitting among the shrubs and trees as they search for food, ever wary of the predators that stalk them from the ground or sky. A striking exception is the mourning dove, our placid, long-tailed neighbor with the melancholy song.

A common resident throughout the U.S. and southern Canada, smaller populations are found as far north as southern Alaska. Though they leave northern sections of their range during the colder months, these doves are hardy, managing to survive the winter on weed seeds and waste grain. Their soft, sad tune is heard by mid March and they are one of the earlier songbirds to nest, usually constructing a crude platform of sticks and straw on a low branch, window sill or directly on the ground. At least two broods are raised in the course of the spring and summer; their young, unlike the squawking, demanding offspring of many species, sit patiently on a tree limb, waiting for mom or dad to arrive with a meal of regurgitated se…

Snows over Gans Creek

Draped across a scenic gorge just south of Columbia, the Gans Creek Wild Area is a 750 acre refuge of forest, immature woodlands, meadows and cedar glades. On this first day of recovery from the recent winter relapse, I headed down to the preserve, equipped with my binos, as usual.

There seemed to be little rebound from the big chill. Though the topsoil was thawing and the trails were muddy, there was a winter-like silence on this early afternoon. Greenery was limited to the cedars, patches of moss and scattered outcrops of grass. The occasional feeding group of chickadees and titmice provided some background noise, which was dominated by the rustling of last year's oak leaves, dangling from barren limbs. The distant drumming of woodpeckers could be heard from time to time and a pair of pileateds moved among the mature forest atop the gorge. Cardinals and a lone mockingbird fed in the cedars while a trio of turkey vultures drifted above the limestone bluffs.

Though my visit wa…

March Monster

The latest winter storm was centered over West Virginia this morning and its cold front stretched from southern Florida to New England. Large and powerful, it raked the Southeast with severe thunderstorms and tornadoes and is now pulling in Atlantic moisture, dumping heavy rains across the East Coast States. Behind the front, heavy snow, up to two inches per hour, is falling sideways, whipped by north winds of forty miles per hour. Two feet of snow will eventually blanket the snowbelt, from northeast Ohio to Upstate New York, and some accumulation will occur as far south as Alabama and Georgia.

Back in Missouri, following a night in the low teens, the sun has returned and the wind has shifted to the southwest. We might reach forty today and should be in the low fifties by tomorrow afternoon. After another brush with winter, spring has regained control. We are experiencing the calm after the storm.

North of Winter

Over the past few days, a deep trough has formed across the Central U.S. as the jet stream took a broad dip to the south. Dropping from the Northern Rockies to the Southern Plains and then northeastward across the mid Mississippi Valley, it has been directing storms along its path. Since the heaviest precipitation develops at and near the interface of cold, dry air and warm, moist air, the greatest impact of the trough has occurred along its southern margin.

As a result, heavy snow fell across eastern Texas, northern Arkansas and southeastern Missouri while areas to the north have received little precipitation. Though temperatures have been very similar, we have enjoyed partly cloudy skies in Columbia while St. Louis, 80 miles to our southeast, received ten inches of snow; even heavier amounts fell in the Ozarks of northwest Arkansas, well to our southwest.

After another blast of Canadian air tonight, the trough is expected to flatten out, the winter conditions will push off to the nort…

The Natural Exercise

Aerobic exercise is an important component of a healthy lifestyle. It is essential to the prevention and management of heart disease, high blood pressure, obesity and type 2 diabetes; it can also play an important role in the treatment and prevention of osteoporosis, tension headaches, depression, constipation and a variety of stress disorders.

With all due respect to marathon runners, triatheletes and extreme sports enthusiasts, walking is the natural form of exercise. And while I appreciate and enjoy competitive sports, having been on swimming and baseball teams for most of my youth, many of them (especially contact sports) can produce a lot of wear and tear over the years. By contrast, man was designed to walk and, unless the individual is careless, walking provides plenty of benefits with minimal risk of injury.

The health benefits of walking are often underestimated. More than an exercise for the leg muscles, walking requires the use of abdominal, back, neck, foot and shoulder musc…

The Drummers of Spring

Throughout the year, the tapping of woodpeckers is a common sound in woodlots, forest preserves and residential areas. Pecking at bark and dead limbs, these specialized feeders search for beetles and other insects, playing a major role in the protection of our woodlands.

Come March, the intensity of their drumming begins to peak as their mating season draws near. Using hollow limbs, wood siding or even metal downspouts, the males rely on percussion to attract females and to claim their territory. Some species, including flickers and red-bellied woodpeckers, combine this drumming with loud, vibrant calls, making them especially conspicuous throughout the early weeks of spring. For birders, March is the ideal month for woodpecker watching; their noisy behavior reveals their presence and the barren trees yield unobstructed viewing.

Midwestern suburbanites are most likely to see northern flickers and both downy and red-bellied woodpeckers in their yards. While hairy woodpeckers can be regul…

We are Star Dust

Current evidence indicates that the Big Bang occured 13.7 billion years ago and scientists believe that the first stars ignited within 200 million years. These original stars, forming from clouds of hydrogen and helium, were giants, thousands of times larger than our sun. Within their furnaces, heavier elements (oxygen, nitrogen, carbon, etc.) were formed during the process of fusion and, when these monster stars exploded as supernovae, even larger, heavier elements were created.

Over time, the formation and explosion of giant stars has enriched interstellar space with the building blocks of other stars, comets, asteroids, planets and life itself. As new stars formed within these clouds of debris, their gravity captured smaller remnants, leading to the development of solar systems; our sun ignited 5 billion years ago and the Earth formed 400 million years later.

All of the elements that make up the rocks, soil, air, fluids, fuels, metals, plants, animals, structures and fabrics of o…

A Telling Wind

Yesterday, a strong southerly wind brought summer-like conditions to Missouri; persisting throughout the day, the gusty flow produced highs in the mid seventies. Unless a hurricane is nearby (very unlikely in the Midwest), such persistent winds herald the approach of a potent cold front. Flowing from an area of high pressure to a zone of low pressure, the winds sweep northward ahead of the advancing front; the greater the pressure gradient, the stronger the winds.

The front arrived last night, accompanied by thunderstorms and heavy rain. This morning, the wind has shifted to the northwest and regional temperatures will fall through the day, from the mid thirties to the mid twenties. Snow should develop by early afternoon as the center of low pressure moves along the front, from the Southern Plains to the Mississippi Valley; 2 to 4 inches is expected in our area.

Such dramatic swings in the weather are typical of March, when spring battles with winter. By later in the month, a highe…

Harbingers of Spring

Though the equinox is still almost three weeks away, the early signs of spring are abundant across Missouri. Morning birdsong has returned in force, the topsoil is thawing and a variety of early bulb plants (winter aconites, snowdrops, crocuses, hyacinths) are beginning to appear. Earthworms are returning to the surface, attracting robins to our greening lawns and munching down the leaf litter that clogs our gardens and hedgerows.

Out in the wetlands, waterfowl are gathering to rest and feed on their journey to the north and the earliest frogs (chorus frogs and peepers) are singing from the shallows. In the fields, cottontails have produced their first litter of the season, just in time for the initial crop of dandelions. And in the woodlands, robins, cardinals and morning doves are pairing off while downy, great horned owlets are already peering from the nest.

While man concentrates on his calendar, counting the hours until the "first day of spring," wild creatures are more i…

Messy March

In the American Midwest, March is the messiest month. Cool, cloudy, breezy weather is the rule, with frequent rain or wet snow. At the same time, the ground is too cold to absorb this moisture and most of the shrubs and trees are still in their winter dormancy. The combination of these factors leads to flooded streams, soggy fields and muddy trails. Furthermore, the winter cold has put nature's housekeepers on hold, leaving plenty of leaves and dead vegetation to clog the woodlands and thickets.

But nature thrives under these conditions. While many humans prefer manicured lawns, clutter-free gardens and dry, even pathways, wild ecosystems depend on the seasonal buildup of nutrient-rich debris, which will fuel the growth of spring and early summer. Flooded fields offer vital rest stops for migrant shorebirds and waterfowl while ephemeral pools are the favored breeding sites for insects and amphibians. Without the mess of March, we could not enjoy the glorious landscape of May!