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Showing posts from June, 2011

A Summer Clipper

During the winter months, most Americans in the central and eastern U.S. dread Alberta Clippers, those pockets of frigid, Arctic air that plummet southeastward to reinforce the seasonal chill. Over the past 36 hours, we have enjoyed the summer equivalent of those clippers; a trough of cool, Canadian air has dipped across the Midwest, pushing the hot, humid air of late June to the south and east.

Unlike the winter invasion, this Summer Clipper is a welcome reprieve, bringing drier air with highs in the upper 70s to low 80s. Unfortunately, like its winter cousin, its effects will be short-lived as the atmospheric trough moves rapidly off to the east and conditions moderate. Indeed, our next heat wave will develop over the coming days, sweeping the thick air of summer back into the Heartland.

While weather patterns are more stable in winter and summer than they are in the spring and fall, the jet stream is a fickle beast and sudden shifts in its course trigger these Canadian invasions.…

No Equipment Required

Anyone who watches cable TV is subjected to numerous ads for exercise equipment; these infomercials offer a vast array of devices that promise a lean, muscular physique, often with little effort on the part of those who use them. In fact, the human body is already equipped with the features needed to produce and maintain physical fitness.

Our musculoskeletal system, under the control of our nervous system, allows us to walk, run, swim, jump, climb and engage in a wide range of physical activities, all of which combat obesity, tone muscles and improve aerobic conditioning. Stair climbing is an excellent example of efficient, no-cost exercise that burns calories, strengthens muscles and benefits the cardiovascular system. For most adults, walking and swimming are the best forms of exercise, offering many benefits with little risk of injury; younger or more fit individuals might add jogging, situps, pushups and a variety of aerobic exercises but, in the end, no external equipment is n…

The Nature of Child Abuse

Mention child abuse and most people think of pedophiles, sweat shops and child prostitution. But there are more insidious and widespread forms that are often overlooked, if not condoned, by human societies.

Parental belief systems and lifestyle choices have a significant impact on the present and future welfare of innocent children. In some cases, these victims are denied access to proper healthcare or education while, in others, poor habits such as overeating, tobacco use and inactivity are instilled. Many children are indoctrinated with various forms of discrimination, whether based on race, gender or sexual orientation and ingrained religious dogma is a common source of fear, guilt and low self esteem.

While many adults overlook these widespread forms of child abuse, they are, in the end, the catalysts for most of our social and political problems. Unless we rescue children from the climate of ignorance and intolerance that envelops their formative years, all future intervention…

Cicada Aftermath

Returning to central Missouri after a brief visit to Florida, we found twigs and clumps of leaves scattered across the lawn; also noticing numerous broken stems in the canopy of some trees (especially the maples and mimosas), we initially assumed that a powerful wind storm had passed through Columbia. On closer inspection, however, we saw grooves on the underside of these terminal branches, indicating that cicadas had produced the damage.

Though their adult life is limited to a week or two, female cicadas can cause significant damage to young trees and shrubs by carving a linear trough along terminal stems in which to lay their eggs. Since tender shoots are favored, young trees are more severely affected and, in some cases, the numerous wounds are fatal. The massive number of periodical cicadas is especially devastating to regional vegetation while the annual cicadas, just now emerging, produce limited damage.

We often ponder how each plant and animal species plays a unique role in…

Into Thick Air

Invited to a family wedding in South Florida, we returned to Longboat Key this week, leaving the hot weather of the Midwest for the equally hot but more humid air of the Subtropics. With lows in the mid 70s (F) and highs in the low 90s, summer is not the ideal time to visit this area.

While winter is the quiet season in more northern latitudes, it is summer that subdues the wildlife of South Florida, causing some species to disperse to the Northern Gulf and Mid Atlantic regions. On the beaches, shorebirds are limited to small groups of turnstones and willets, joined by the solitary great blue herons and yellow-crowned night herons that stalk the shore. Small flocks of royal terns and laughing gulls, extremely vocal for much of the year, now hunt in relative silence or lounge in docile groups on the baking sand. Brown pelicans, always rather mute, patrol the coast in silent squadrons, diving now and then to grab a meal.

Away from the beach, white ibis monitor broods of growing youn…

Human Paternalism

Father's Day seems like a good time to reflect on our paternalistic approach to other species. Self-designated caretakers of the planet, we often interfere with the lives of "lower" animals, rescuing them from natural predators, storms and other threats that play an important role in the balance of ecosystems.

Of course, we must try to minimize unnatural human impact on animal populations; poaching, pollution and habitat destruction via agriculture or development are continuous threats to their welfare. On the other hand, our tendency to micromanage the natural environment by culling predators, introducing alien species or directly interfering with the life cycle of other species is frought with danger. Even our humane attempts to feed orphaned creatures or rescue beached whales is ill-advised; nature is not sentimental and the adversity suffered by one animal may be a crucial bounty for another.

If we truly care about the health of natural ecosystems, it is best that…

Colorado's Alpine Wildlife

In Colorado, the alpine timberline lies at about 11,500 feet, somewhat higher on south-facing slopes and a bit lower on shaded, northern flanks of the mountains. This biologic barrier, characterized by krummholz (stunted, wind-shaped conifers) and pockets of bristlecone pine, marks the upper edge of the Subalpine Zone; above timberline is the alpine tundra, a sun-drenched ecosystem of lichen-splattered rocks, glacial lakes, tussock grass, cushion plants and an amazing diversity of wildflowers.

Ravens are the most conspicuous birds of the alpine tundra, joined by American pipits, horned larks, mountain bluebirds and those ubiquitous American robins during the warmer months. White-tailed ptarmigan, though difficult to spot, are also fairly common and brown-capped rosy finches congregate near the rock-rimmed lakes. Avian hunters include golden eagles, prairie falcons and northern goshawks and the open woodlands of timberline attract white-crowned sparrows, Wilson's warblers, Clark…

Landscape & Soul

As a child, in Cincinnati, I was always attracted to images of the West, whether they appeared on calendars, in Life Magazine or on our black and white TV. Since my family only vacationed on Lake Erie or along the Gulf Coast, I did not have a chance to visit the Western U.S. until I was twenty-five, the year that my wife and I took a road trip to interview at medical residency programs.

In that fall of 1975, we headed west on I-40 and finally escaped the humid air and greenery of the East in western Oklahoma. My first glimpse of western mountains came as we approached Albuquerque and, over the next week, we circled through the desert landscapes of New Mexico and Arizona. Turning northward, we climbed across the Mogollon Rim, passed the snow-capped summits of the San Francisco Peaks and visited the spectacular scenery of Grand Canyon, Zion and Bryce Canyon National Parks. For me, the emotional zenith came as we rounded the north edge of the Mt. Nebo massif, in Utah, and the Wasatch…

The Non-Prairie Warbler

Prairie warblers are among the more common summer warblers in the Midwest, Mid-Atlantic and Southeastern U.S; despite their name, they do not inhabit prairies. Rather, these colorful and active birds favor overgrown pastures, cedar groves, pine barrens and other pockets of second-growth forest.

Nesting and feeding close to the ground, prairie warblers are easily identified by their olive back, yellow face and underparts and black streaks on their cheeks and sides; their tail wagging habit also aids identification. Primarily insectivores, gleaning prey from the leaves and limbs of small trees and shrubs, they will consume berries on occasion. Their cup-shaped nests are placed within ten feet of the ground and 2-5 eggs are produced; of interest, female prairie warblers consume the egg shells after hatching.

Prairie warblers that breed across the central and eastern U.S. winter in Mexico, Central America or the Caribbean. A subspecies permanently resides in South Florida, favoring ma…

Warm Front Storms

Severe thunderstorms and torrential rain generally develop within the warm sector, just ahead of an advancing cold front. Energized by a potent zone of low pressure and a dip in the jet stream, the cold air knifes beneath the warm, humid air, producing lift, heavy precipitation and potential tornadoes.

But storms can also develop as warm fronts move into cooler air along the back edge of atmospheric troughs. Over the past few days, a stationary front has curved through the Heartland, separating intense heat in the Southern Plains from relatively cool air across the Upper Midwest and central Mississippi Valley. Tied to a low over eastern Kansas, this front has begun to nudge to the northeast; in concert, counterclockwise winds around the low have been sweeping Gulf moisture across the front, producing waves of thunderstorms through Iowa, Missouri and southern Illinois.

While these warm front storms are not as intense as those along cold front squall lines, they may yield significant…

Utah's Powder Keg

Famous for deep powder that attracts skiers from across the globe, the Wasatch Front of Utah is about to unleash its bounty on those who live along its base. Thanks to a persistent atmospheric trough that produced a chilly, wet spring, the snowpack is near record levels and has barely begun to melt, a process that generally peaks in May. When summer heat suddenly arrives, a torrent of meltwater will sweep through the steep canyons of that majestic range, inundating the towns and cities that lie in its path.

Unlike in other areas of the country, the rivers that drop into the Great Basin soon spread across the flat terrain, forming broad, shallow lakes that evaporate in the intense sun of the high desert. Of course, Salt Lake City and other urban centers now occupy that basin and, when reservoirs are unable to contain the flow, flooding results. In light of the deep snowpack and delayed melting cycle, such a scenario appears to be unavoidable.

The bounty of mountain snow is vital to…

Prickly Pear Cacti

Prickly pears, members of the genus Opuntia, are the most widespread and heavily utilized cacti on our planet. Native to the Americas, more than 200 species now grace the globe, many of which are under cultivation for food, livestock feed and a variety of materials.

While most species of prickly pear colonize desert or semiarid life zones, they are found from southern Canada to South America and are the only cacti native to the eastern U.S. Characterized by fleshy pads (nopales) which harbor long, fixed spines and small, fine, barbed glochids, most prickly pears grow in dense clusters, low to the ground; however, some species branch upward to form shrubs or small trees, reaching heights of seven feet or more. Prickly pear flowers, which bloom from April to June (depending on latitude) are most often yellow or orange but may be red, pink or purple in color. Their globular fruit, also coated with glochids, is consumed by birds, rodents, deer, peccaries and other wildife and have bee…

The Desert Owl

Elf owls, the smallest owls in North America, are summer residents of the Sonoran Desert in southern Arizona; some inhabit the Chihuahuan Desert of southernmost New Mexico while others breed in dry country along the Rio Grande River of southern Texas. Less than six inches tall, these tiny raptors are best identified by their yellow eyes, white eyebrows and round, tuftless head.

Calling from a potential nest cavity in April, the male attracts his mate and both parents incubate the eggs (usually 2-4) for several weeks. Nest cavities, always more than ten feet from the ground, are abandoned woodpecker holes in saguaro cacti or in sycamores along streams near the base of mountain ranges; gila woodpeckers usually sculpt the saguaro cavities while flickers and acorn woodpeckers provide those in riparian areas. Strictly nocturnal, elf owls feed primarily on flying insects but may grab a scorpion or ground beetle; during the breeding season, they are often active at dusk but are otherwise …

Carrabassett Flashbacks

In 1981, after a hot, humid summer in Arkansas, I flew to Maine to look at a practice opportunity. The town was rather small but the medical community was welcoming and, of course, the prospect of living amidst the rugged mountains, glacial lakes, deep woods and spectacular seascapes of that State was surely appealing.

During my visit, one of the older physicians, sensing my enthusiasm for the local geography, took me for a drive up the Carrabassett River Valley, through the fragrant Northwoods, studded with ponds and bogs. The air was cool, mountains loomed in the distance and signs warning of wayward moose were spaced along the roadway. In contrast to the sluggish, muddy streams of the Deep South, the clear, chilly waters of the Carrabassett rushed above gravel beds and splashed among ancient boulders, dropped by the Pleistocene ice sheets.

For a variety of reasons, we declined the opportunity in Maine and ended up in the dry, sunny climate of the Front Range. Though I have no r…

Madera Canyon

The mountain ranges of southeast Arizona offer steppingstones of forest for birds migrating between the Sierra Madres of Mexico and the Rocky Mountains of western North America. In addition, these sky islands provide cool, moist retreats for the birds and other wildife that reside in the Sonoran Desert, concentrating their populations and making them more accessible to humans who hope to observe them. Harboring a mix of Mexican and North American species, these ranges are thus renowned as superb birdwatching sites and Madera Canyon is among the more popular destinations.

Incising the northwest flank of the Santa Rita Mountains, 25 miles SSE of Tucson, Madera Creek rises along the crest of the range (an elevation of almost 9500 feet) and drops 7000 feet to the floor of the desert. Within its spectacular canyon, varied life zones attract a tremendous diversity of plant and animal life, including more than 200 species of resident and migrant birds. Among the more treasured sightings…

The Nature of Wildfire

The massive wildfire that is ravaging northeast Arizona is surely causing hardship for many humans and its scar will stretch across the landscape for many years to come. But wildfires, like floods, hurricanes and other weather-related "disasters" have been essential to the health of natural ecosystems throughout the history of our planet.

Usually triggered by lightening and fueled by drought, wildfires serve to clean out our forests, recycle nutrients and protect our prairies. For many plants, as with lodgepole pines, wildfire is an essential factor in the reproductive cycle, releasing seeds and setting the stage for germination. Furthermore, fire removes invading, alien plants that are unable to withstand its effects, clearing the landscape for native species.

While a large number of creatures may succumb to wildfire, most animals that live in fire-prone ecosystems adapt to these seasonal events, escaping the flames within burrows or using their natural skills to flee th…

Fence Lizards

Fence lizards are the most common and widespread lizards in the eastern and central U.S. The northern fence lizard ranges from the Mid-Atlantic region to the edge of the Great Plains and is especially abundant in the wooded hills of the Appalachian and Ozark Plateaus; the southern subspecies inhabits the pine woodlands of the Coastal Plain, from the Carolinas to Texas.

Named for their habit of basking on fence posts, these lizards spend much of the day in trees, chasing down insects, spiders, caterpillars and other invertebrates. Hikers often encounter them as they sprint across trails or scurry through the leaf litter but these agile reptiles usually escape to the safety of a tree, hiding on the opposite side of the trunk.

While both sexes are drab colored, with gray-brown scales, males sport patches of blue on their throat and sides during the breeding season. Mating occurs soon after hibernation and up to 15 eggs are laid by late spring, hatching in late summer or early autumn. …

The Brilliant Wader

Natives of tropical South America, Central America, the Caribbean, South Florida and the Texas-Louisiana Gulf Coast, roseate spoonbills are distinctive waders that are sought by birders and photographers alike. They favor shallow, coastal bays where they feed on small fish and marine invertebrates, grasping prey with their sensitive, paddle-shaped bills. Due to their bright pink plumage and long, reddish legs, roseate spoonbills are often mistaken for flamingos; in fact, they are closely related to ibis and, like their cousins, fly in linear squadrons with necks outstretched.

Roseate spoonbills nest in mangroves or on offshore islands with low vegetation, often in large, mixed colonies that include herons, egrets, ibis, cormorants and pelicans; 1-4 eggs are incubated by both parents and the young will fledge within two months of hatching. Juvenile spoonbills often wander farther north in summer, appearing along the upper Gulf Coast and, occasionally, in the lower Mississippi Valley…

Hazy, Hot & Humid

After a cool, wet spring, we have gone directly from April to July here in central Missouri. That dreaded summer forecast for hazy, hot and humid weather is blaring from the TV and we expect highs in the nineties (F) for most of the coming week.

The heat has driven the periodical cicadas into a frenzy and, by mid afternoon, they are everywhere, zooming through the air, buzzing from the trees and covering every exposed structure. Due to chilly, wet weather through much of May, they are two weeks behind schedule and should plague our area well into June. While their noisy din is annoying for humans, their massive numbers provide a bonanza of nutrition for birds and other predators and one can only begin to imagine the wealth of nutrients that their decomposing bodies return to the soil and plants.

Never a fan of hot, humid weather, I am already looking forward to the invigorating air of fall; more than two weeks before the summer solstice, it's not a good sign that heat advisorie…

Hominids & the Sahara Desert

The vast Sahara Desert, which stretches across North Africa, began to form in the late Miocene and early Pliocene, some 10 million years ago (MYA). South of this geophysical region, gorillas diverged from the hominid line about 9 MYA and chimpanzees followed 7 MYA. By 4.5 MYA, Australopithecus appeared in the Rift Valley of East Africa and, by 2 MYA, Homo erectus had evolved.

While the Sahara may have been a natural blockade to the northward migration of the earliest hominids, the Pleistocene Epoch (2 MYA to 10,000 YA) brought wide swings in the global climate, marked by four periods of glaciation. During these glacial periods, a cool, wet climate caused the Sahara to contract, opening corridors of savannah that likely permitted ancestral hominids to migrate northward, into Eurasia. Following earlier migrations of Homo erectus, Neandertals began to leave Africa about the time that humans were first appearing, some 150,000 years ago, and occupied Europe by 100,000 years ago. Man r…

Exploiting Human Nature

As a physician, I regularly witness the less attractive features of human nature but it has been the explosion of cable channels and social networking that has fully exposed, if not celebrated, our obsession with power, sex, celebrity, death and various forms of human turmoil.

Though religious and political scandals, corporate greed, domestic violence and civil rights abuses have occurred throughout history, modern technology assures that we are constantly exposed to these dark human traits. While it is important to stay informed about the ills of society and while the exposure of such activity is essential to its eradication, a wide variety of cable channels feed on dysfunctional human behavior, turning human tragedy into a lucrative form of entertainment.

Even more disturbing, the rise of social networking, encouraged throughout society, feeds this exhibitionism, offering immediate fame to those who take advantage of our dark obsessions. As individuals, we have little control over …

New England Tornadoes

While we usually associate tornadoes with the Great Plains and Southeast, as we observed yesterday, they can occur in any region of the lower 48 States. Coming on the heels of tragic storms in Missouri and Alabama, the deadly tornadoes in Massachusetts seemed to suggest a doomsday scenario but their occurrence was merely a reflection of the typical weather patterns that produce such storms.

For the past few days, a dome of hot, humid air dominated the eastern U.S., from the Gulf of Mexico to New England; this atmospheric ridge was the product of an active, late spring jet stream, which dipped through the West and then looped northward across the Great Lakes and southern New England. To its north, Canadian high pressure was dropping southward, producing a clash zone across Massachusetts that was further energized by the turbulent jet stream. As typically occurs, severe thunderstorms ignited when the cold air undercut the hot, humid air and intersecting winds(the westerly jet and str…

Common Snappers

Though widespread across North America, from the foot of the Rockies to the Atlantic Seaboard and from southern Canada to the Gulf Coast, common snapping turtles favor the muddy bottom of shallow lakes, ponds and rivers and are not often encountered by the casual naturalist. When seen, they are usually lumbering across country roads, searching for nest sites or new feeding grounds.

Despite their reputation as vicious predators, snapping turtles are opportunistic omnivores, feeding on a wide variety of plant and animal life, including carrion; while they will snare an occasional duckling or young muskrat, they are more likely to dine on decaying carp, aquatic vegetation, frogs, water snakes and smaller turtles. Mating is also opportunistic, occuring from mid spring to late autumn; since females can store viable sperm for years, one encounter is sufficient to fertilize several clutches of eggs. Up to ninety eggs are deposited in a pit, dug by the female in late spring, and will hatch…