Posts

Showing posts from November, 2009

From Southwest to Northeast

An upper level low is spinning over the Southwest this morning. Attached to a cold front, that stretches from El Paso to Chicago, the storm is pulling in moisture from the Gulf of California, producing mountain snows and valley rains across the Four Corners region; the higher elevations of West Texas can also expect snow from this storm.

Forecast to move eastward and then northeastward over the coming days, this low pressure will begin to tap Gulf of Mexico and Atlantic moisture and drop significant rain across almost all of the East, from the Gulf Coast to New England. Depending upon the relative positions of the cold front and the central low, snow accumulation could be significant in the Northern Appalachians.

Such storms systems, which typically move from west to east across North America, illustrate the dynamics of our weather, combining the effects of wind direction, lift (from both the low and the topography), air temperature and atmospheric moisture; the latter develops as air m…

The Okavango Delta

Rising in the highlands of eastern Angola, the Okavango River flows southeastward, crosses a sliver of eastern Namibia and enters the northwest corner of Botswana. There, it spreads into a broad, braided delta which, during the cool,wet climate of the Pleistocene, fed a vast inland lake. As the climate warmed, this south-central region of Africa dried out, the lake receded into scattered salt pans and tectonic activity, associated with the East African Rift, altered the regional topography.

Through all of this, the Okavango Delta persisted, draining into the sands and seasonal lakes of the expanding Kalahari Desert; covering more than 6000 square miles, it is the largest inland delta on the planet. Flow through the Delta peaks from May through August, coinciding with the dry season of the surrounding grasslands and desert. As one might expect, this oasis effect attracts huge and varied concentrations of wildlife to the Okavango Delta, moving in from the parched landscape. Just as the O…

The Nature of Parenting

Throughout most of the animal kingdom, parenting does not occur. In "lower animals," up through amphibians and reptiles, fertilized eggs and live young are cast into the world, expected to fend for themselves. With few exceptions, parenting is limited to birds and mammals and, for the most part, it is a maternal responsibility. Encompassing efforts to feed, protect and instill survival skills, the process may take weeks to years, depending on the species.

In mammals, females are instinctively equipped to nurse, protect and teach their young; failure to do so generally implies underlying illness (physical, mental or emotional). In some species, males may take part as providers and protectors but, as we all know, their dedication to these responsibilities is far from reliable. Early humans, like other primates, were likely polygamous and the male's attention to individual sons or daughters was surely lacking. As human society advanced, monogamy has been encouraged through a…

Thanks to Nature

On this annual Day of Thanksgiving, there are many reasons to be thankful for our natural world. Spectacular sunsets and star-filled skies come to mind, as do mountain vistas, majestic rivers, colorful canyons and beautiful seascapes. And across these varied landscapes is a fascinating diversity of life, from algae to redwoods, amoebae to elephants, krill to blue whales.

Of course, nature is not mindful of our appreciation and does not seek our approval. In fact, we are part of her realm. Nature is both around us and within us; our bodies, minds and souls, like the components of a tree, have evolved from more primitive forms and occupy their unique place on the spreading web of life. Today, we express our gratitude for the experience.

Wild Gobblers

As we approach the great American feast day, it seems appropriate to consider the wild relative of our main dish. A native of North America, the wild turkey once inhabited much of the Continent, from southern Canada to Mexico. Extirpated from many areas by over-zealous hunting, our largest game bird has been making a comeback in recent decades, primarily due to habitat protection, reintroduction programs and improved conservation management.

A bit leaner than their domestic cousins, wild turkeys are nearly as large; adult males often weigh 20 pounds or more. Despite their size, these birds are capable of rapid flight for short distances and, equipped with long legs, usually escape predators by running into cover. Wild turkeys favor open woodlands and are best observed near the border of fields and forest. After feeding on acorns, seeds, berries, corn and insects through the day, they roost in trees for the night.

In spring, adult males gather harems of up to fifteen hens; sparring with …

Raking Leaves

Raking leaves, to the extent that I bother, is one of my favorite forms of yard work; it takes me outdoors, provides exercise, is not terribly exacting and always (by my own choice) occurs on a mild autumn day. Yesterday, with partly sunny skies, a minimal breeze and a high near 60 F, offered a perfect opportunity.

Not inclined toward masochism and dedicated to recycle the leaves to nourish the plants in our yard, I rake them into mounds around the trees or into the shrub and flower beds that line the fences; by mid spring, most have disappeared into the soil. I'm also inclined to stop frequently to take in the sights and sounds of autumn, my favorite season of the year. Yesterday afternoon, the squirrels were busily gnawing on black walnuts, their squeaky efforts ringing through the yard. Woodpeckers were especially active, represented by a pair of downies, several red-bellies, a host of flickers, a hairy woodpecker at the feeder and a lone yellow-bellied sapsucker. The usual mix …

The Nature of Intolerance

Many people...far too many...see this world in black and white. For them, every human idea, trait or point of view is either right or wrong, good or bad, divine or evil; there is no room for dissent, discussion or compromise.

This rigid approach to life is usually ingrained in childhood and reinforced by a cloistered youth, with exposure to a limited circle of relatives and friends. Those who continue to live in such confinement, not motivated to explore the "outside world" via education or travel, tend to retain their simplistic and dogmatic views. In turn, these provincial attitudes foment intolerance, often surfacing as racism, religious zealotry and other forms of discrimination.

Intolerance of other ideas and points of view, a product of early, self-righteous reinforcement by parents or mentors, hinders one's ability to function effectively in relationships and in human society as a whole. Faced with this reality, unwilling to compromise and incapable of trusting …

November Dusk

After nearly a week of clouds, rain and fog, the sun broke through in central Missouri this afternoon and, as the sun set on the western horizon, a clear sky stretched above Columbia; its pale, blue expanse was broken only by a crescent moon to the southwest and sparkling Jupiter to the south. As I trudged home in the fading dusk, it was easy to appreciate that winter is winning its battle with fall.

The cool, dry air was invigorating but the quiet season is clearly taking hold. Sparrows and mourning doves drifted into stands of pine and cedar for the night and only the sharp chirps of cardinals rang through the neighborhood. Squirrel nests, back lit by the red glow of dusk, harbored their industrious tenants while timid cottontails ventured into the fading light for their nocturnal feast; if they escape the gaze of our resident owls, they'll spend tomorrow in their dens.

November takes us from bright October to dark December, from warm days to cold nights. In the Northern Hemispher…

Lowdown on the Leonids

Far from an expert on astronomy, I do try to catch the major meteor showers each year, including the Perseids, in August, and the Leonids, in November. The latter, remnants of the Tempel-Tuttle comet, peak on the nights of November 17-18 and, due to their metallic composition, tend to leave long vapor trails. The Leonids, named for the illusion that they arise from the Constellation of Leo, are especially abundant every 33 years, when the comet has recently crossed Earth's orbit; the shower of 1966 produced thousands of meteors per hour.

This year, a stubborn low, centered over the Midwest, has kept Missouri under a thick overcast, with intermittent fog, cold rain and snow showers. Expected to drift slowly to the east, this weather system should exit our region by the weekend but, by then, the 2009 Leonids will be history.

In fact, I've been unable to observe the Leonids for several years now; whether in Missouri, Colorado or Ohio, the skies have not cooperated. But nature is no…

Snows in the Night

In the midst of a cold, steady rain, the distinctive call of snow geese descended from the skies late last evening. Hitching a ride on northerly winds, they were off to marshlands along the Gulf of Mexico, where they will spend the winter months.

Though I could not see them in the dark, cloudy sky, their calls were no less inspiring and suggested the presence of several flocks, strung out from east to west; eventually, as the travellers moved on to the south, their high-pitched calls faded in the night. While these flocks will escape the Midwest winter, others will follow in their wake, gathering at staging areas along the Missouri and Mississippi Rivers; hopefully, I'll get the chance to visit them before they, too, move on to the Gulf.

Until then, I will listen for other flocks in the night, stirred by the wildness of their collective voice. For theirs is a message of freedom, a call to join them as they follow the sun.

Prairie Streams

The Great Plains of North America were once covered by a rich prairie ecosystem, which extended from western Ohio to the Rocky Mountain foothills. Today, most of the grasslands have been replaced by cropfields and ranches, significantly diminishing the natural diversity of this region.

Even before the prairies were lost to the farmer's plow and the cattleman's herds, riparian (stream-side) communities were vital to the Great Plains ecology, providing food, shelter, nest sites and natural highways for the varied wildlife of this vast and open country. Now that cropfields cover much of the region, these streams, with their associated woodlands and wetlands, are critical ribbons of natural habitat across an altered landscape; nevertheless, riparian habitats are among our most threatened natural communities, often falling victim to stream diversion and pollution.

Prairie streams concentrate the wild residents of the Great Plains and offer attractive settings for wildlife observation…

Presence of Mind

Brain power is what separates humans from all other species on our planet. This trait, responsible for all of our accomplishments, from articulate speech to flush toilets, has opened our world to discovery and given us the opportunity to understand the complexities of our environment, our bodies and our relationships. It is, after all, the basis for the human condition.

Despite the many advantages that brain power affords, it also has a tendency to complicate our lives. The capacity for memory, essential to the learning process, opens the door to rumination and regret; in like manner, our ability to anticipate the future often leads to worry and dread. Though the past was not as wonderful as we sometimes remember and the future will not be as daunting as we might imagine, these cerebral preoccupations often cloud and influence our present thoughts and actions.

Indeed, in comparison with many others species, humans have a diminished presence of mind. Not endowed with the acuity of sigh…

Starling Ballets

Despised by avid birders and by those who live near their crowded roosts, European starlings have become one of the most successful species in North America, inhabiting almost all of our natural ecosystems. In doing so, they have often displaced native birds by usurping nest cavities or by consuming much of the wild food crop.

Nevertheless, these prolific birds offer some benefits, primarily related to their taste for grubs and other harmful insects. In addition, for those who travel across America's farmlands, they provide entertainment in the form of spectacular aerial displays; these starling ballets are observed during the colder months, when the maligned immigrants gather in huge flocks.

Often first mistaken for a puff of black smoke, the shape of the flock changes constantly as the birds spiral and dip above the countryside, instinctively moving in a coordinated mass. At certain angles, they may disappear from view, suddenly reappearing like a flash card image at a football st…

San Rafael Swell

Between Green River, Utah, and the eastern edge of the Wasatch Plateau, 70 miles to the west, Interstate 70 crosses a broad ridge, adorned with spectacular rock formations. This topographic dome, up to 40 miles east-west and 100 miles north-south, is known as the San Rafael Swell.

At the onset of the Eocene Period, almost 60 million years ago, this region was characterized by flat terrain, a subsurface layer cake of Paleozoic and Mesozoic sediments overlying the deep, Precambrian basement. At the surface, early Tertiary deposits lay on successively older rock layers (from top to bottom: Cretaceous, Jurassic, Triassic, Permian and older Paleozoic sediments). Then, during the Eocene, the Precambrian basement folded upward as a broad dome, lifting the overlying layers of rock which have since eroded into the formations that we see today; resistant sandstones and limestones form ridges, domes and pinnacles, separated by valleys of softer shale and mudstone.

Atop the Swell, the Tertiary and …

Tardy Geese

Most birds migrate in response to the solar cycle, departing their breeding or wintering grounds in concert with a given period of daylight. Waterfowl, on the other hand, tend to move along in response to a combination of weather conditions and food availability; this is especially true during their fall migration when flocks may winter further north if snow and ice are not disrupting their ability to feed.

In Metro Denver, the migrant Canada geese usually arrive during the first week in November, significantly augmenting the smaller populations that are permanent Colorado residents. By now, the fields and skies of the Front Range are usually full of these noisy visitors; in early morning and late afternoon, numerous flocks pass overhead, moving between reservoirs (where they spend the night, safe from predators) and their favorite grasslands. As of today, the influx of migrants has been minimal and I suspect that mild conditions in Canada and the northern U.S. have, as yet, not for…

Plum Creek Valley

South of Denver, the terrain gradually rises toward the Front Range foothills and the broad Palmer Divide. Drained by Plum Creek and its tributaries, this region has been dissected into a scenic landscape of valleys, ridges and mesas; scrub grasslands cover the lower elevations, juniper and oak thickets adorn the valley walls and stands of ponderosa pine spread across the higher terrain.

Long used for cattle ranching, industry and urban development have spread through the valley over the past century and, in recent decades, suburban sprawl has invaded the uplands. Nevertheless, if one gets away from these sites of human impact, it is easy to appreciate the natural beauty that once characterized all of the Plum Creek Valley. Mule deer are especially common here, feeding along roadways and foraging on the hillsides. Elk winter in the valley and the howls of coyotes echo across this spectacular terrain. Magpies, scrub jays, crows and flickers lend their voice to the wild landscape while g…

Abert's Squirrels

Those who hike in the ponderosa parklands of our western foothills and mesas have a chance to see Abert's squirrels, one of North America's more unique and interesting mammals. Closely associated with ponderosa pine forests, which are best developed between six and nine thousand feet, these "tassel-eared squirrels" are found in the Rocky Mountain chain, from southern Wyoming to northern Mexico, and across the Colorado Plateau.

Best identified by their prominent ear tufts, Abert's squirrels are primarily arboreal, feeding on the seeds, cones, buds and inner bark of ponderosa pines; they also consume a variety of berries, fungi and carrion. Their nests are constructed with pine needles and twigs and are placed high in mature trees, usually at the junction of a large branch and the central trunk. Mating, which follows a day-long chase by several suitors, occurs in late winter or early spring; 2-4 young are generally born in May or June.

The color of Abert's squirr…

Avian Kites

All across the Great Plains, hawks, gulls and vultures dipped and soared in the deep blue sky on this sunny, November day. Strong south winds, building ahead of the next cold front, triggered the aerial display and pushed summer-like weather into the region.

As expected, red-tails dominated the show but a few rough-legged hawks were encountered on the High Plains and a golden eagle soared above the Palmer Divide, in eastern Colorado. Even the northern harriers and prairie falcons, which typically fly and hunt close to the ground, could not resist a chance to bank and soar with the others. In central Kansas, just east of Russell, a huge flock of sandhill cranes circled high overhead, seemingly making little progress in the stiff, southerly head winds.

While some (if not most) of these aerialists were in the process of hunting, many seemed to be playing in the steady breeze, dipping and gliding above the wide open terrain. If only we had the ability to join them!

A Mast Bonanza

Acorns are abundant across central Missouri this year. Well beyond the capacity of natural consumers to eat or store them, the nuts and their fragments coat lawns, roads and walkways.

These nuts are, of course, the fruit of oak trees; more than 600 species of oak can be found across the globe and more than 60 are native to North America. Most oaks are deciduous trees but some, including the live oak of the southeastern U.S., are evergreens; acorn production begins as early as 10 years and as late as 50 years after germination, depending on the species. The white oak family (which also includes bur, gambel, post, chinkapin and chestnut oaks, among others) produce acorns that mature within 1 year and do not have a bitter taste. The red oaks (including scarlet, pin, black, live and willow oaks, among others) produce acorns that mature in 2 years and, due to the presence of tannins, have a bitter taste.

Oaks produce acorns every year but, in mast seasons, which occur every 2-7 years, a dram…

Big Brother Jupiter

Jupiter shines high in the southern sky during the evening hours this month. More than five times as far from the sun as we are, this massive gas planet has a diameter that is 11 times the diameter of Earth; indeed, Jupiter's size, relative to the sun, is comparable to Earth's size relative to Jupiter. Though mostly gaseous and without a solid surface, Jupiter's mass is greater than twice that of all the other planets combined.

Composed primarily of hydrogen and helium, Jupiter is thought to have a solid core, similar to that of Earth. Its banded atmosphere, composed of ammonia clouds, is colored by varying quantities of sulfides and hydrocarbons and undergoes constant turbulence due, in part, to the planet's high rotational speed (a full rotation occurs within 10 hours). This rapid rotation also induces a bulging of Jupiter's equatorial region, giving the planet an ovoid shape with flattening at the poles. Four large moons, first observed by Galileo in 1610, ar…

Nature's Revenge

After more than six months of being contained, trimmed, beautified and doused with chemicals, nature exerts her revenge on the American suburbanite in November. Showering lawns, gardens, roofs and walkways with a copious mix of leaves, twigs and seed pods, she reminds us that manicured landscapes are not her style.

So the fastidious homeowner, intent on maintaining order, must rake, scoop and remove nature's debris. Ever mindful of his watchful neighbors and the expectations of his community, he recycles this "yard waste" in appropriate bags and places them on the curb (in an orderly fashion) for all to see. He is, indeed, a green-minded citizen.

Those of us more accepting of nature's way are slow to respond to this onslaught of plant debris. We know that wind and rain and snow will remove much of it, that mold and bacteria will degrade the larger components and that a variety of creatures (earthworms, moles, mice, squirrels) will make use of its edible contents. …