Saturday, May 31, 2014

Storm on the Bay

Yesterday afternoon, fed by warm, humid air from the Gulf of Mexico, thunderstorms began to form east of Sarasota Bay; their slate-gray bases obscured the distant landscape while their massive thunderheads billowed into the sky, reflecting light from the late day sun.

By early evening, one of the storms had grown out of proportion to the others, sucking in their heat and moisture and darkening the skies east of Sarasota.  We watched from our condo across the Bay as this massive storm drifted in our direction, producing flashes of lightning and sharp claps of thunder.  Ahead of that atmospheric monster, a pair of magnificent frigatebirds circled over the bay, keeping a safe distance from its vanguard of clouds.  Brown pelicans, white ibis, ospreys and a variety of herons, sensing the storm's approach, took refuge in mangrove islands while laughing gulls flew toward the strong, outflow winds, hovering above the whitecaps to snare a fish.

As quickly as the storm had developed, it subsided, raking the bay with easterly winds and pummeling its surface with torrential rain but sparing the homes and condos on Longboat Key.  For a weather buff, like myself, it was fascinating to watch the birth and demise of that powerful thunderstorm and to observe its impact on the bay and its residents.

Friday, May 30, 2014

Greeted by Storms & Kites

After some hiking in the Cumberland Plateau, we continued southward toward our condo on Longboat Key, Florida.  Approaching the Tampa area, we were greeted by a series of thunderstorms, characterized by intense lightning and torrential rain.  Weather reports indicated that an onshore flow was occurring on both sides of the Florida peninsula, sweeping in copious moisture to feed the late afternoon storms.

In bright sunshine, between two of the thunderstorms, a trio of swallow-tailed kites soared above the Interstate, feeding on insects that the rains had forced from the vegetation.  Permanent residents of South America, some of these beautiful raptors breed and summer in Florida, in adjacent coastal regions of the U.S. and in Central America.  They favor wooded marshlands, where insect prey is abundant; while these kites feed primarily on flying insects, they also glean insects and small lizards from the forest canopy and are known to consume fruits on occasion.

It was certainly appropriate to be greeted by two of Florida's more alluring traits: towering thunderstorms and exotic wetland birds.  Hopefully, we'll encounter plenty more over the coming week.

Thursday, May 29, 2014

Lookout Mountain of the Southeast

Like the Allegheny Front in western Pennsylvania, Lookout Mountain, which stretches from Chattanooga, Tennessee, to Gadsden, Alabama, represents the eastern edge of the Appalachian (or Cumberland) Plateau.  Standing atop this massive ridge, one can appreciate the puzzle-like topography of the Plateau to the west, dissected into a maze of ridges and valleys by a dendritic network of streams; to the east, the lower Ridge & Valley Province angles northeast to southwest, composed of parallel ridges and relatively broad valleys.  East of the Ridge and Valley swath are the higher summits of the Blue Ridge, reportedly visible from Lookout Mountain on clear days.

At the north end of Lookout Mountain, Point Park, a National Military Park, commemorates the important role that this natural overlook played during the Civil War and protects some structures from that era.  From its lofty perch, some 1300 feet above the Tennessee River, one enjoys a broad panorama of Greater Chattanooga and of the River's tortuous course, flowing down through the Ridge and Valley Province, looping past Chattanooga and then entering the Cumberland Plateau above Nickajack Lake. Meanwhile, turkey and black vultures soar along the limestone cliffs, as if to proclaim that such a striking view is not so unique for them.

The highest point on Lookout Mountain, just under 2400 feet, lies in Georgia and a number of rugged canyons incise the walls of this massive ridge.  Of special interest to most human tourists are Ruby Falls and Rock City, heavily advertised on barns and billboards throughout the eastern U.S.  More on those commercial sites in a future post.

Wednesday, May 28, 2014

Grundy Forest Natural Area

Driving southeast on Interstate 24, one encounters the first ridges of the Appalachian Plateau (known in Tennessee as the Cumberland Plateau) about halfway between Nashville and Chattanooga.  The highway soon climbs onto one of those ridges at Monteagle, a pleasant town that provides close access to many components of the South Cumberland Recreation Area; established in 1973, this Recreation Area consists of ten State Parks and Natural Areas scattered across the ridge.

After discussion of dayhike opportunities with a staff member at the Visitor Center (about 4.5 miles from Monteagle on U.S. 41 South), we settled on the Gundy Forest Natural Area, just southeast of Tracy City.  A two mile trail loop leads down to Big Fiery Gizzard Creek, broken by scenic rapids and cascades and hemmed in by its spectacular limestone gorge.  Giant slump blocks, having broken from the walls, lie in or near the stream and massive Canadian hemlocks, relics from the Pleistocene, rise within the creekside forest.  Before ascending back to the parking area above Little Fiery Gizzard Creek, we hiked further south along the main branch to Sycamore Falls and Chimney Rock; the entire 3.2 mile hike took about 2 hours to complete (including stops for photos and wildlife observation; the latter included a copperhead snake on rocks above the creek).

Before leaving the area, we also visited Foster Falls, a 60-foot cascade 8 miles southeast of Tracy City and the Sewanee Natural Bridge, 2.5 miles south of Sewanee via Route 56 (about 8 miles south of Monteagle).  My next post will cover our visit to Lookout Mountain, which rises above Chattanooga and extends southwestward into Georgia and Alabama.

Monday, May 26, 2014

The Nature of Soldiers

Throughout human history, young men and women have been the fodder for war.  Whether they volunteered or were drafted into service, they have bravely and loyally followed the orders of presidents, commanders, kings, queens and warlords.

While we should not question the courage, sacrifice and patriotism of those combatants, it is appropriate to seek justification for the conflicts in which they participate.  Some soldiers have fought to defend their country or to expel those who occupied their homeland while others have struggled in the service of invaders, engaged in a campaign based on imperial, political or religious zealotry.

Today, we honor those who served in America's wars, from the Revolution to Afghanistan.  Many lie entombed in military and civilian cemeteries throughout this country and across the globe, most having died in their late teens or twenties and many having died in vain.  Among those who survived the atrocities of combat, most have returned with some degree of physical injury or mental torment that will haunt them (and their loved ones) for life.  Hopefully, we humans will soon evolve beyond the need to enlist soldiers to resolve our disputes.

Sunday, May 25, 2014

Cattle Egrets in the U.S.

Though cattle egrets were first observed in North America in the 1940s and were breeding here by the early 1950s (see Global Egret). they are not widespread in the U.S.  Permanent populations are found in Florida, along the Gulf Coast and in California while summer residents have spread along corridors where riverine marshlands, open country and cattle have invited their presence.

Summer populations of cattle egrets are found along the Atlantic Seaboard (as far north as New England), up through the lower Mississippi Valley (where the floodplain is broad) and westward along the corridors of the Rio Grande, Red and Arkansas Rivers.  While they inhabit the Bootheel region of Missouri, I have never seen them along the Missouri River and, though I have seen large flocks in Oklahoma and southern Kansas, I have never encountered cattle egrets on my many journeys along Interstate 70 (between Missouri and Colorado).  Then again, small flocks may be found near reservoirs in eastern Colorado during the summer months, presumably having migrated north from Mexico or westward along the Arkansas River; some California residents also move up the Pacific Coast during the warmer months.

In late summer and early autumn, however, cattle egrets are highly mobile and may turn up along almost any North American coast or river corridor.  As their population continues to expand, they are likely to become permanent residents across the southern States and summer residents in all other areas that offer the basic requirements mentioned above; by then, only mountainous regions and desert landscapes will be excluded from their North American domain.

Saturday, May 24, 2014

Mountain Plovers

The only thing "mountain" about mountain plovers is that they summer and breed in the Mountain Time Zone.  Preferring short-grass prairie and other flatlands with sparse vegetation, they nest on the High Plains, from southernmost Canada to eastern New Mexico and West Texas; small populations have also been found in Utah.

Soon after arriving on the High Plains in spring, mountain plovers pair off and scoop out a number of shallow depressions, one of which is eventually used for the nest.  As with most "shorebirds," the young are active soon after hatching and hunt for insects with their parents.  Those hoping to encounter mountain plovers are advised to drive along graveled country roads of the High Plains, especially in the National Grassland areas; since they prefer sparse vegetation, these birds are often best found in and around prairie dog colonies.  Rather tame, they seldom fly off as your vehicle approaches, preferring to run away or flatten themselves against the stark terrain to avoid detection; among their natural enemies are prairie falcons, Swainson's hawks, swift fox, coyotes and rattlesnakes.  Challenged by loss of prairie habitat, mountain plovers have adapted to the presence of cattle (surrogates for the great bison herds) and are not officially listed as a threatened species by the U.S. Fish & Wildlife Service.

Come fall, mountain plovers head for wintering grounds in the valleys of California or in desert grasslands of southern Arizona, northern Mexico or West Texas; those that breed in southern regions of the High Plains may not migrate if insects and other terrestrial invertebrates remain available.  Since they tend to wander about during the autumn migration, it is then that they may turn up in unexpected habitat or distant from their usual range.

Friday, May 23, 2014

Southern Plains Monsoon

The annual Southwest Monsoon, which develops during the summer months, results from low pressure over the northern Baja and high pressure over the Southern Plains; these atmospheric conditions combine to induce moisture flow from the Sea of Cortez and the western Gulf of Mexico into the Four Corners region and northward along the Front Range.

Over the past few days, a similar phenomenon has occurred further east, bringing heavy rains to eastern New Mexico and West Texas and feeding thunderstorms as far north as Colorado and Wyoming.  An upper level low over the Desert Southwest and high pressure over the Southeastern U.S. have funneled moisture into the Southern Plains; this atmospheric "squeeze play" results from a counterclockwise flow around the low pressure and clockwise winds along the outer rim of the high pressure dome.

While the annual Southwest Monsoon generally waxes and wanes from June through August, the current moisture plume over the Southern Plains will likely break down within a few days; indeed, the core of the moisture appears to be moving eastward today and is now centered over the Texas-Oklahoma line.  Then again, if the high pressure dome over the Southeast refuses to budge (or even expands westward), heavy rains may persist over and near the Texas Panhandle, bringing floods to a drought-plagued landscape.

Thursday, May 22, 2014

Summer Mode at Eagle Bluffs

After months of hosting frenzied migrants, beginning with snow geese in February and ending with various songbirds and shorebirds in early May, Eagle Bluffs Conservation Area has entered its summer mode.  On my visit this morning, even the Canada geese and red-winged blackbirds were relatively calm and quiet.

The goose parents proudly escorted their offspring along the grassy lake shores and mother wood ducks ushered their broods across secluded, marsh-lined coves.  Numerous great blue herons stalked the shallows, while, out on the calm pools and channels, there were more water snakes than waterfowl.  Belted kingfishers, a few great egrets, killdeer and spotted sandpipers were the only other aquatic birds to make an appearance.  Though woodland songbirds were diverse, they had abandoned the feverish activity of the past few weeks and turkey vultures, awaiting the late morning thermals, lounged on the graveled levees.

As I left that Missouri floodplain refuge, the call of a northern bobwhite rang from the riverside woodlands, a nostalgic sound from the summers of my youth and one that I seldom encounter these days.  Of course, I moved away from their primary range many years ago but, even within that range, their population has dropped dramatically; suburban sprawl and agriculture are primarily responsible for that decline, having destroyed and degraded much of their natural habitat.  Its call today was thus both a pleasant surprise and confirmation that the lazy, hazy days of summer have begun.

Wednesday, May 21, 2014

Genetics & Disease

The study of human health reveals that there are a group of diseases that are clearly genetic in origin, caused by defective genes or chromosomes; many of these disorders, such as the muscular dystrophies, present early in life and, unless specific therapies are available, significantly decrease that individual's expected life span.

A host of other diseases also have been recognized to "run in families," indicating that affected individuals have a genetic predisposition to that condition; cardiovascular disease is included in this group.  While the inherited factors increase the risk for these health disorders, that risk may be diminished by lifestyle choices that are known to counter the development of the pathologic process (e.g. engaging in regular aerobic exercise and avoiding tobacco use in the case of cardiovascular disease).

While we often assume that common infections affect everyone equally, it has become evident that one's immune health is closely linked to genetics and that any given individual may be more or less susceptible to specific infectious agents and/or to the complications of those infections; complications may include conditions such as autoimmune disease, certain malignancies and multiple sclerosis, among many others.  In like manner, our genes also govern our relative sensitivity to a wide variety of toxic agents, including alcohol, tobacco and environmental carcinogens.  In the end, our genome is the most important determinant of our overall health while preventive measures and the availability of therapeutic intervention play secondary though vital roles.

Tuesday, May 20, 2014

Rivers of the Flint Hills

The scenic Flint Hills of eastern Kansas are composed of Permian strata, lifted and carved into a maze of ridges and valleys by numerous streams.  The Kansas River, which forms from the merger of the Republican and Smoky Hill Rivers at Junction City, Kansas, curves along the northern border of the Flint Hills, receiving flow from McDowell Creek, Deep Creek and Mill Creek (west to east), which drain the north rim of Hills.  The northeast portion of the Flint Hills is drained by the upper tributaries of the Marais des Cygnes River, which flows eastward into Missouri to join the Osage River.  Both the Kansas and Osage Rivers are, in turn, major tributaries of the Missouri River.

The central and southeastern regions of the Flint Hills are drained by the tributaries of the Neosho River (including the Cottonwood River which flows west to east); the Neosho itself flows southeastward and then southward, joining the Arkansas River in northeastern Oklahoma.  The Verdigris River and its tributaries drain the south-central portion of the Flint Hills; flowing southward, the Verdigris also joins the Arkansas River in Oklahoma.  Finally, the Walnut River incises the southwestern edge of the Flint Hills; flowing SSW and passing east of Wichita, it enters the Arkansas River at Arkansas City, Kansas.

Many who read Nature's Blog will probably have little on no interest in this litany of Kansas rivers.  However, those of us who are fascinated by the landscape and topography of this planet have a keen appreciation for the work of rivers and how they have sculpted the geography that we encounter.  They are, after all, more than nature's sewers and, to truly understand the lay of the land, we must know where the rivers flow.

Monday, May 19, 2014

In Rattlesnake Country

At the trailhead for the Sharptail Ridge Open Space preserve, south of Denver, a sign warns of rattlesnakes in the area.  Of course, similar signs are found at many other parks along the Colorado Front Range and across large portions of our country.

Acknowledging the warning (both appropriate and legally correct), we headed south on the main trail, gradually climbing onto the grass-covered ridge.  While we gazed ahead from time to time, making sure that a rattler was not basking on the path, our focus was on the magnificent scenery, on the colorful wildflowers and on the local wildlife; the latter included a prairie falcon, vesper sparrows, western meadowlarks, Say's phoebes, western kingbirds and rufous-sided towhees.  Unfortunately, on several visits to that preserve, I have yet to encounter a sharp-tailed grouse.

Atop the ridge, we enjoyed both a picnic lunch and broad views of the Front Range and Metro Denver.  Soon after beginning our descent, we passed two women on horseback who warned of a rattlesnake further down the trail.  Suddenly, that warning sign took on more significance and, paying less attention to the scenery, wildflowers and wildlife, we focused on the path before us; though I hoped to catch a glimpse of the dangerous reptile, I wanted to do so from a safe distance.  Alas, the snake was not encountered and our descent from Sharptail Ridge was far less enjoyable than the climb; after all, warnings are one thing and reality is another.

Sunday, May 18, 2014

Lazuli Buntings

On a hike through Roxborough State Park yesterday morning, I encountered most of the birds common to the foothill shrublands of Colorado's Front Range; among these were scrub jays, canyon wrens, white-throated swifts, Say's phoebes, rufous-sided and green-tailed towhees, black-headed grosbeaks and lazuli buntings.  The latter species is a common summer resident of shrubby hillsides and wooded, riparian corridors throughout the American West.

Lazuli buntings begin to arrive in Colorado by early May, when the colorful males use their unique song (distinct for each bird) to establish their territory and lure a mate.  Cup shaped nests are placed low in the shrubbery and 3-4 eggs are generally laid.  Feeding on insects, seeds and berries, lazuli buntings may be seen gleaning their prey from vegetation, fly-catching from an exposed perch, or foraging for seeds on the ground.

Their annual molt begins in late summer, before the autumn migration begins, and is completed at a number of staging areas across the Desert Southwest before completing their journey to wintering grounds in western Mexico.  Closely related to the indigo bunting of the central and eastern U.S., lazuli buntings are known to interbreed with their cousins where their ranges overlap; as indigo buntings continue to spread westward along riparian corridors of the Great Plains, such hybridism will steadily increase.

Saturday, May 17, 2014

The Nature of Thought

Thought is the intellectual process of digesting personal experience, acquired knowledge and the ideas of others; it is through this process that we develop our sense of self, including the convictions and philosophy that govern our life.  Though many other animals are capable of learned behavior, none seem to share our capacity for complex thought.

Of course, thought does not necessarily lead to truth.  While our personal experience is unimpeachable, the quality of our knowledge depends upon its source and the ideas of others may have little or no foundation in reality.  Fortunately, if exercised, thought allows us to sift through these sources of information, weighing their value in the context of one another.

Our capacity for thought may be impaired by brain injury but its process is more often corrupted by trusted individuals who strive to influence our life.  The latter is especially prevalent during our formative years when we are most receptive to the ideas of parents, family members, friends and other authority figures (teachers, ministers, community leaders, etc.).  As adults, we possess the intellectual freedom to formulate our own ideas, discarding ingrained convictions and assumptions that no longer fit our changing view of life and our place in the Universe.

Thursday, May 15, 2014

Swallow Squadrons

On this cool, sunny morning along the Colorado Front Range, we headed down to South Platte Park.  In the course of our hike, the resident birds were, for the most part, neither diverse nor abundant.  Red-winged blackbirds, yellow warblers, house wrens, robins, yellow-rumped warblers and brown cowbirds accounted for most of the birds in the trees and shrubs while only mallards and western grebes plied the lake waters.

An exception were the swallows, represented by tree, barn, cliff and violet-green species.  Swooping above the reservoir, ponds and lakes in large, mixed flocks, they feasted on rising clouds of insects.  While the tree swallows have graced the Park since late March, the barn and cliff swallows arrived in late April and the violet-green swallows, which will soon move into the foothills and mountains, have just recently returned from the south.

Those swallows not strafing the open waters gathered on power lines in large, linear flocks; seemingly obeying strict military protocol, one squadron would depart as another was arriving, assuring that the insects were subjected to a steady attack.  As spring progresses, these social birds will become less gregarious though the cliff swallows will nest in colonies under bridges along the South Platte or on rock walls of foothill canyons; barn swallows, as their name implies, will seek out nest sites in a variety of human structures while tree and violet-green swallows will nest in tree cavities or bluebird boxes.  By late summer, the massive flocks will reconvene, fueling up for the autumn migration.

Wednesday, May 14, 2014

Ditch Digging

Prior to this morning, my volunteer activities with the Carson Nature Center, at South Platte Park, had consisted of participation in waterfowl counts.  Then, noting a volunteer project day on the Center's calendar (the nature of which had yet to be determined), I signed up.

As it turned out, our group was assigned to clear a drainage channel between the Nevada Ditch and Cooley Lake, along the west edge of the South Platte River floodplain; silt and extensive stands of cattails had begun to impair flow though the channel.  Armed with shovels, hoes and limb pruners, we worked for almost three hours to clear a swath less than fifty yards long.

Such projects, relying on manual labor rather than motorized tractors or trenchers, gives one an immediate (and lasting) appreciation for the achievements of the farmers, ranchers and laborers that first settled the American West.  On the other hand, throughout this morning's work, one could not help but wonder how long the fruit of our labor would remain effective; given the earth-moving capacity of flash floods and the prolific nature of cattails, the channel will surely re-clog in the near future.  In the end, man's determined efforts to control the forces of nature prove to be futile.  

Tuesday, May 13, 2014

Westward into Winter

Heading back to our Colorado farm yesterday morning, we left Columbia under hazy skies; the temperature at dawn was 71 degrees F and the dew point was nearly as high.  Just west of Topeka, Kansas, we crossed the cold front of the massive storm system that pummeled the Southern Plains and Midwest with severe thunderstorms and tornadoes over the past few days.

After driving through a heavy band of rain, studded with lightning, we emerged on the back side  of the front and the temperature began to fall.  Through central and western Kansas, strong northwest winds rocked our pickup as we sliced through a chilly mist and, by the time we reached the Colorado line, the temperature had fallen into the upper thirties (of course, the wind chill was significantly lower).

The first pockets of snow appeared along the highway in eastern Colorado, increasing in extent as we approached the Palmer Divide, north of Limon.  Though up to 8 inches had fallen in parts of Metro Denver, most had melted under the potent May sun by the time we reached our Littleton farm; there, the temperature was 37 degrees, to be followed by an overnight low in the mid twenties.  May upslope snowstorms are not uncommon along the Colorado Front Range, generally occurring every 3-4 years; while the heavy, wet snow smashes flower beds and often takes down tree limbs; it doesn't last long.  We'll be back in the fifties today and in the eighties by this weekend.

Monday, May 12, 2014

Life's Tragedies

Many humans face tragedy in their life, whether from war, accident, illness or natural catastrophe.  For some, such events are accepted as fate or destiny, evidence of God's master plan; such views provide personal comfort since, they conclude, there must be an underlying reason for the tragedy.  Others, myself included, cannot believe in such a sadistic deity and accept tragic events as the consequence of risky behavior or, more commonly, the result of simple bad luck (genetics included).

Those who put themselves in harms way for the thrill (e.g. sky diving), to pursue their professional passion (e.g. war photojournalists) or simply for social or personal reasons (e.g. tobacco or drug use), accept a certain degree of risk with their lifestyle.  Others endure personal tragedy through no fault of their own, generally as innocent victims of war, accident, criminal behavior, natural catastrophe or illness;  in such cases, they or their loved one was simply a victim of circumstances (genetic, geographic, social or otherwise).

In some ways, those who accept fate and place their life in God's hands have an advantage; if the nature of their demise is preordained, they need not worry about healthy lifestyle choices and might be more willing to engage in high risk activity than the nonbeliever who senses a degree of control over his or her life.  It seems to me, however, that we can reject both the mysticism of destiny and the inertia of fear, living life to its fullest while accepting the random nature of death; after all, if one believes that we have but one life to live and that death is death, they are more likely to make the most of their time on this planet.

Sunday, May 11, 2014

More Mothers than Fathers

On this Mother's Day, it's appropriate to acknowledge that, in nature, there are more mothers than fathers.  Among the many invertebrates, fish and amphibians that utilize external fertilization, the designation of genetic parenthood is not always possible, as clouds of eggs and sperm mix in the sea or in a pond.

Among most other animals, monogamy is uncommon though couplings may occur for a given breeding season, thereby defining genetic fathers and mothers.  However, in some species, especially in large herbivores, males spar for mating rights; the victors are then free to assemble their harems and impregnate the females.  Examples include wild horses, elk, musk ox and bighorn sheep, among many others; similar relationships occur among some carnivores and primates, where the alpha male does the breeding.  Even humans participate in this imbalance, as young men irresponsibly impregnate a number of women or, as more responsible citizens, donate to their community sperm bank; then, of course, there are men that father children with a string of wives (a practice far more common than the reverse).

It thus follows that there are more mothers than fathers on Planet Earth.  On Mother's Day, we stop to honor that responsible majority.

Saturday, May 10, 2014

Grass Plovers at Eagle Bluffs

Thanks to a heads-up from a friend and fellow birder who was arriving at Eagle Bluffs as I was leaving, I was fortunate to observe four upland sandpipers along the entry road to that fabulous floodplain refuge.  In fact, this morning's sighting was the first time that I have encountered these terrestrial shorebirds at Eagle Bluffs Conservation Area, in central Missouri.

Upland sandpipers, once known as "grass plovers" and later called "upland plovers," are summer residents of prairie grasslands across the Great Plains, Alaska, south-central Canada, the Great Lakes region and the Northeastern U.S.; east of the Mississippi, they are best found at airports or in hayfields.  Easily identified by their distinctive silhouette, upland sandpipers generally arrive on their breeding grounds in May and begin to depart for South America by mid-late July; indeed, they spend about 2/3 of the year on the grasslands of Patagonia.  Nesting on the ground, their eggs are laid in a shallow depression, dug by the parents; the precocious young begin to feed soon after birth, scouring the ground for insects.  Adults, which often perch on fenceposts, feed primarily on grasshoppers but also consume other insects and seeds.

Nearly hunted to extinction, upland sandpipers have made a significant comeback but continue to be threatened by loss of prairie habitat; while they have adapted to less pristine grasslands, their population will surely never rebound to the abundance that European settlers encountered as they first entered America's Heartland.  It was then that "grass plovers" were hunted for food and sport and the vast prairie grasslands were converted to "amber waves of grain."

Friday, May 9, 2014

Preventing Dementia

As the Baby Boomers enter their late sixties and seventies, increasing attention is focused on dementia and other diseases of the elderly, especially since the costs of treating individuals with those conditions is expected to rise dramatically.  Almost every day, the results of another study are released in the media, associating dementia with a variety of lifestyle choices that were made earlier in life.

First of all, such data should be viewed with some suspicion; while many are based on scientific analysis,  isolated studies are of limited value and must be confirmed by other scientific investigations.  To date, the pathophysiology of Alzheimer's disease (the leading cause of dementia) is poorly understood and one's age and the presence of this disorder in the family history are the only clear risk factors.  On the other hand, dementia caused by vascular disease in the brain is predisposed by the same factors that increase risk for vascular disease in other organs of the body (i.e. the heart, kidneys, etc.); it is thus reasonable to conclude that hypertension, chronic tobacco use, diabetes, hyperlipidemia and a family history of cardiovascular disease are important risk factors and that a healthy, well balanced diet, regular aerobic exercise and appropriate medical control of associated risk factors should reduce the incidence of this form of dementia.  Finally, it has become evident that repeated head injury, such as occurs in football players and boxers, is responsible for another form of dementia, often presenting in middle age.

Hopefully, continuing research will lead to effective preventive therapies for Alzheimer's disease.  In the meantime, individuals are advised to adhere to lifestyle choices that reduce the risk of both vascular disease and brain trauma.  In addition, current evidence suggests that ongoing cerebral "exercise", as occurs with reading, games, academic pursuits and other cognitive activities, may slow the onset of dementia.  Should early signs of dementia appear, it then becomes important to have frank discussions with family members, caretakers and health care providers, clarifying the level and intensity of medical care that one finds personally acceptable; too often, patients with dementia end up dying in hospitals (sometimes in ICUs) when they would have preferred to forego aggressive intervention and to have died at home.

Thursday, May 8, 2014

Blocking Highs

Domes of high pressure may sit above an ocean or land mass for an extended period of time, shunting storm systems around their periphery; in such cases, these atmospheric ridges are called blocking highs. Within the dome, air is sinking and heating up, suppressing cloud formation and precipitation; indeed, most of Earth's deserts lie along latitudes where persistent domes of high pressure tend to form.  In the Northern Hemisphere, winds move clockwise around the dome while, in the Southern Hemisphere, winds move counterclockwise along their periphery.

Stationary high pressure domes are often responsible for droughts, shunting rain or snow producing storms away from the area over which they lie; they may also induce air stagnation, preventing the inflow of fresh air and aggravating pollution levels.  On the other hand, blocking highs may be protective, impairing the formation of hurricanes and tropical storms or steering them away from the coast; then again, they may direct those storms toward other coastal areas (e.g. a blocking high over the Southeastern U.S. may shunt a hurricane toward Mexico or Texas).

The severe conditions that gripped the central and eastern U.S. last winter was due, primarily, to a persistent ridge of high pressure over the Western U.S.  Beneath that dome, those in the West enjoyed mild, sunny, dry weather (exacerbating California's drought) while Pacific storms were directed into southern Alaska and western Canada; this mild flow severely diminished the snow pack in those regions but dislodged polar air, causing it to plummet through the central and eastern U.S.  This past week, a high pressure ridge has covered the southeastern quadrant of North America, bringing summer conditions well ahead of schedule; fortunately, the dome is sliding eastward and a Pacific cold front is expected to arrive today, igniting thunderstorms and sweeping in cooler, more seasonable weather.

Wednesday, May 7, 2014

Along Grindstone Creek

Grindstone Creek Nature Area, in Columbia, Missouri, is another excellent area for birding.  Riparian woodlands line the stream and limestone bluffs rise along the valley walls; enveloped by the creek's broad loop are open woodlands, cedar groves and a restored prairie, offering a diverse habitat for avian residents and visitors.

Yesterday morning, before encountering my first bird, I came across a male five-linked skink, sunning himself on the wooden planks of a bridge; his bright orange face, contrasting with a light brown body, indicated that breeding season is well underway.  Numerous bird species were seen along the winding path; indigo buntings, northern cardinals, eastern bluebirds, gray catbirds, American goldfinches and red-bellied woodpeckers were among the more common residents.  Warblers were represented by yellow, prothonotary, cerulean, Nashville and yellow-rumped warblers, common yellowthroats and yellow-breasted chats.  Other sightings included warbling and white-eyed vireos, brown thrashers, blue-gray gnatcatchers and house wrens; of special interest was a flock or a dozen or more white-crowned sparrows, gorging themselves on dandelion seeds at the edge of the graveled path (and fueling up for their journey to northern Canada).

In addition to the many colorful birds, the refuge was adorned with a beautiful mix of woodland wildflowers, including yellow flower panicles on the buckeye trees.  A lone box turtle plodded across the trail, oblivious to my presence, and the silky chambers of tent caterpillars festooned many of the small trees.  As is usually the case, yesterday's birding walk led to many expected sightings but some chance discoveries as well; the latter are what keep us enthused and engaged.

Tuesday, May 6, 2014

Public Prayer

Yesterday, the U.S. Supreme Court upheld the right of government organizations to begin their meetings with a public prayer, as long as that practice does not favor one religion over another.  They did not seem to be concerned that their ruling favors religious faith over a lack of belief in a prayer receptive deity.

This unfortunate decision also demonstrates little appreciation for the social, political and economic pressure that, while not openly expressed, is imposed on the participants.  One can easily imagine that this pressure (and the consequences that come with it) is more significant in some regions of our country than it is in others.  After all, intense religious faith tends to be associated with politically conservative and poorly educated sectors of the population; within such groups, a lack of engagement in or enthusiasm for public prayer may be a significant political and/or economic liability.

One wonders why we don't favor "moments of silence," during which individuals might formulate their own thoughts.  Need we be guided in those thoughts by a visiting priest, rabbi, minister or Muslim cleric?  In my opinion, mysticism is a personal right that should not be inflicted on other members of society.

Monday, May 5, 2014

Heavenly Days at Eagle Bluffs

Eagle Bluffs Conservation Area, southwest of Columbia, is an excellent destination for birding during any season.  However, the diversity of species peaks in early May, when summer residents have returned and migrants are still moving northward through the Missouri River Valley.  Today was no exception.

The lakes, ponds, channels and sloughs attracted a wide range of water birds, including great blue herons, great and snowy egrets, a trio of white-faced ibis, blue-winged teal, American coot, pied-billed grebes, double-crested cormorants, wood ducks, belted kingfishers, a flock of least terns and a large number of migrant shorebirds, dominated by lesser yellowlegs.  A pair of sandhill cranes foraged in an adjacent field and a bald eagle surveyed the scene from a dead cottonwood; muskrats, aquatic turtles and cricket frogs were also active on this mild spring morning.

Riparian woodlands along the Missouri River are always full of songbirds and, in early May, a visitor can observe most of the species that summer in or migrate through the State.  Today, indigo buntings, northern orioles, blue-gray gnatcatchers, eastern wood pewees and house wrens were most numerous though a lone yellow-breasted chat was most conspicuous, preaching from a sunlit limb.  Prothonotary warblers are also common in these woodlands and the distinctive call of the barred owl is often heard here in April and May.

Sunday, May 4, 2014

Evening Visitors

As I am prone to do during the pleasant weather of mid spring and early autumn, I stepped out back last evening to see who might be visiting our property.  During my thirty minutes of observation, I discovered three transients amidst the diverse group of summer residents.

A male blackpoll warbler methodically combed the trees of our wood border, feasting on insects before he moves on toward northern Canada.  More active was a male Connecticut warbler, identified by his sharp white eye rings, grayish head, olive back and yellow abdomen.  The third evening visitor was a solitary vireo, foraging in the upper branches of a black walnut tree; he's likely headed for the forests of the upper Great Lakes region.

These three migrants were joined by the usual mix of cardinals, house wrens, red-bellied woodpeckers, grackles, chickadees, robins and house sparrows.  A pair of ruby-throated hummingbirds zoomed through the yard, squadrons of chimney swifts raced overhead, turkey vultures drifted toward their nightly roost and a female cowbird surveyed the woodland, searching for a nest to parasitize.  While the common, local residents may be more vital to our regional ecology, the travelers remind us that all of Earth's ecosystems are connected and that suburban rest stops now play a crucial role in that network.

Saturday, May 3, 2014

Warbler Weeks

The last week of April and the first three weeks of May are of special interest to veteran birders.  During this period, warblers are streaming northward through North America; while most are heading for Canadian forests, some will settle down to breed and summer in woodlands or wetlands of the Lower 48.

Small, colorful insectivores, most warblers are active feeders, flitting among the branches of trees or shrubbery.  As a result, they are often difficult to observe and identify, posing a challenge for both novice and veteran birders alike; their diversity, represented by some 55 species in North America, only adds to the confusion.  Some are relatively easy to identify; black-and-white warblers forage along limbs and tree trunks in the manner of nuthatches, yellow-breasted chats often sing (or lecture) from an exposed perch, and ovenbirds and waterthrushes feed on the ground and along streams (respectively).  Among the more common summer residents are yellow warblers, American redstarts, common yellowthroats, yellow-breasted chats, prairie warblers and prothonotary warblers; the latter, which nest in tree cavities, are best found in stands of bottomland timber.

As they migrate northward, warblers often congregate at areas just south or north of major bodies of water; there they may be found in large, mixed flocks and are more readily observed.  Cape May, New Jersey, on the northern side of Delaware Bay, and Magee Marsh, on the south shore of Lake Erie, are two such areas; at either of these sites, a birder might observe a dozen or more warbler species on a morning or late day visit in early to mid May.

Friday, May 2, 2014

Returning to October

After more than a week in the balmy, humid air of Ohio, we returned to Missouri yesterday afternoon, arriving at dusk.  Stepping from my pickup, we were enveloped in cool, dry air, reminiscent of October.  Adding to that illusion, a white-throated sparrow was singing his homesick tune, not yet off to Canada; indeed, this may have been the latest that I have heard that northern songbird in a central Missouri spring.

The fall-like air is courtesy of the recent storm system that pummeled the Southeast with tornadoes and floods.  On the backside of its massive circulation, cold air has dropped into the Heartland, leaving some snow across the Northern Plains and keeping afternoon highs in the mid 50s (F), from the Front Range to the Mississippi Valley.  Today, a southwesterly flow will begin to warm the region and, by tomorrow, May will have reclaimed Missouri.

While many residents were surely not pleased to experience October conditions in early May, I found the air to be exhilarating.  After all, the hot, humid summer will arrive soon enough and, when we are caught in its oppressive grip, this brief, chilly invasion will become a fond memory.

Thursday, May 1, 2014

Birth, Death & Survival

Following the gradual thaw of March and the steady transition of April, an explosion of life occurs in May and June across the Northern Hemisphere.  More direct solar radiation supplies the energy, warming the landscape, igniting thunderstorms and fueling photosynthesis; the latter, which takes place in the leaves and stems of green plants and in the cells of cyanobacteria and algae, utilizes water and carbon dioxide to produce glucose and to enrich the atmosphere with oxygen.

In turn, insects, certain reptiles and many birds and mammals feast on those plants, including their nectar and fruits.  The insects, having overwintered as eggs or having emerged as nymphs from ponds, soil or rotting vegetation, begin to reproduce and provide food for carnivorous plants, larger insects, fish, amphibians, reptiles and insectivorous birds and mammals; fish and amphibians also provide sustenance for a host of reptiles, birds and mammals.  Finally, reptiles, birds and mammals feast on one another (herons on lizards, otters on turtles, gators on muskrats, snakes on nestlings, hawks on mice, etc.).

For any given species, survival is dependent on a reproductive rate that outpaces (or at least matches) the loss of individuals to predation, injury, illness and advanced age.  At the bottom of the food chain, plants and a host of invertebrates (including worms and insects) are highly prolific, as are primary consumers such as mice, cottontails, frogs and fish.  The higher a species lies on the food chain, the lower its reproductive rate tends to be; indeed, apex predators are especially dependent on the reproductive success of their prey species since their own reproductive rate is often governed by prey availability.