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Showing posts from November, 2012

Landlubber on the Coast

After ten days on the Gulf Coast of South Florida, we will head north tomorrow.  It has been a pleasant, relaxing visit with fabulous, mild weather, beautiful scenery and a fascinating mix of plant and animal life to observe.  Nevertheless, landlubber that I am, I yearn for the interior of North America, with its more varied topography and distinct seasons.  I need hills and mountains, canyons and valleys, forest and prairie, snowscapes and deserts.

Though sea coasts harbor unique vistas and wildlife, inland lakes, rivers and marshes offer a wealth of aquatic ecosystems to explore and the wide variability of Temperate Zone habitats possess a broader range of species.  While Midwestern States do not entice tourists to the degree that Florida does, naturalists know that they are home to a rich diversity of landscape and wildlife; unfortunately, the majority of Americans are oblivious to that fact.

Tropical creatures that we are, most of us enjoy connecting with the tropics or sub-tropic…

Crested Caracaras

The crested caracara, also known as the Mexican eagle, northern caracara or Audubon's caracara, is a widespread member of the falcon family, found primarily in Mexico, Central America and northern South America; it also inhabits southern Arizona, south Texas and the dry prairies of central Florida.  Unlike other falcons, it is not a swift, aerial hunter; rather, this omnivorous bird is primarily a scavenger and usually hunts on the ground.

Preferring dry, open country, including desert grasslands, cattle ranches and savannas, the crested caracara is generally found alone or in small groups though it is frequently in the company of vultures.  Carrion is its primary food source though it also consumes insects, small birds, small mammals, lizards and eggs.  Mating occurs in mid-late winter (depending on latitude) and a clutch of 2-4 eggs is laid in a bulky nest of sticks, usually in a lone tree surrounded by grassland.  Very slow to mature, young caracaras are unable to fend for them…

East to the Prairie

This morning, we left the watery landscape of the Gulf Coast and headed east to the dry prairie region of central Florida.  Following Florida 72, we crossed I-75 and entered a landscape of cattle ranches, flatwoods, dry prairie, freshwater swamps, canals, meandering rivers and citrus groves.  Sandhill cranes were very common (most often seen in pairs or small flocks) and certain birds, including cattle egrets, wood storks and anhingas, were far more common than they are near the coast.  East of Arcadia, now on Florida 70, we began to see crested carcaras, raptors that are closely associated with the dry, open grasslands; other prairie birds included American kestrels, loggerhead shrikes and numerous turkey vultures.

At Okeechobee, Florida, we stopped to view the great, freshwater lake of south-central Florida, the second largest lake that lies totally within the lower 48 states; since that vast but shallow lake is surrounded by a levee, our view was from the edge of wetlands that rim …

Feisty Sanderlings

Sanderlings, one of the most widespread shorebirds on Planet Earth, breed on the Arctic tundra and winter along sandy beaches and mudflats as far south as southern Argentina.  Medium-sized and easily identified, they gather in flocks during the colder months and are known for their habit of racing along the edge of the surf, probing the wet sand for marine invertebrates.

Sanderlings are common on the beaches of Longboat Key, Florida, from late summer to mid spring and, as noted above, are generally seen in small groups or moderate sized flocks.  Today, however, these winter visitors seemed to be in a feisty mood, feeding alone and squabbling with their neighbors; in one case, a pair of these "cute" shorebirds actually engaged in brief but harmless combat.  While male sanderlings are known to be highly territorial in the Arctic (allowing some females to produce a clutch of eggs with more than one suitor), I have never observed this behavior on their wintering beaches. Since j…

Beach Topography

I have long been enamored with landscape and, the greater the topographic relief, the better.  So, while I thoroughly enjoy our visits to Florida, with its rich marine and terrestrial ecosystems, I find the flat terrain less than appealing.

On the other hand, the sandy beaches of the Atlantic and Gulf Coasts offer an opportunity to witness the natural processes of deposition and erosion in their most elemental form and the constant interaction of wind, water and sand provides insight into the gradual yet no less relentless development of landforms across the globe.  In areas where the sand is tightly compacted (and thus more resistant to erosion), steep-walled escarpments form, collapsing in places to mimic the rock slides along our western canyons.  In other regions, where the sand is relatively loose and easily displaced, incoming waves produce broad, flat plains, dappled by transient pools that soon fill with sand, shells and other debris, pushed in from the sea or swept across the…

Leaping Rays

After a beach walk on Longboat Key, Florida, I stopped to survey the flat, blue Gulf of Mexico.  Scanning with my binoculars, I noticed a large splash about 100 yards offshore and focused on that location.  Within a minute the creature leaped again and I was able to identify it as a large ray; a third leap further confirmed the sighting and suggested that the ray had a wingspan of at least 5-6 feet.

While this was my first experience with a leaping ray, their habit of doing so is well known and well documented; indeed, a search on Google or YouTube turns up plenty of photos and videos.  The historical record also includes unfortunate injuries and at least one death related to large rays (up to 300 pounds or more) jumping into fishing boats.  On the other hand, there is no scientific consensus as to why the rays leap in the first place; explanations range from mating behavior to escaping predators (i.e. sharks).  Of course, these marine creatures may simply be stretching their muscles …

Longboat's Shifting Beach

Longboat Key is a long, narrow barrier island off the west coast of Florida, stretching between Anna Marie Island, off Bradenton, and Lido Key, off Sarasota.  Angled NW to SE, its Gulf of Mexico side is lined with beaches while its eastern edge, along Sarasota Bay, is a mosaic of tidal marshes, mudflats, mangrove islands and residential developments; the latter are generally protected by seawalls and many are accessed by boat channels from the Bay.

The northwest tip of Longboat Key, known as Greer's Beach, is subject to regular sculpting by tropical storms and wave action.  As a result, it often harbors a mix of tidal shallows and sand spits and has defied attempts to permanently restore its condition.  While humans may prefer a wide, gently sloping beach for sun-bathing, beach games, fishing and shelling, the fickle nature of this shore appeals to marine birds, many of which nest and roost along this coast and find off-shore fishing to be productive, the result of changing and up…

Gulf of Mexico Gannets

The northern gannets of North America breed in six large colonies along the Gulf of St. Lawrence and the coast of Newfoundland.  Adults arrive at those rocky headlands by early April and depart by early October, wintering at sea along the coastal shelf, from Maine to Mexico.  Non-breeding juveniles spend their first three years at sea before returning to their ancestral breeding sites.

Prior to the Deep Horizon disaster, in April of 2010, it was assumed that only a small minority of North American gannets wintered in the Gulf of Mexico; this assumption was based on the results of past tagging studies.  However, a large percentage of the oiled birds found along the Gulf Coast proved to be northern gannets, primarily juveniles; the predominance of juveniles reflected the time of year of the disaster, when most adults had returned to Canadian breeding grounds.  In fact, more recent studies, using GPS, have revealed that 25% of North American gannets winter in the Gulf of Mexico at some p…

Longboat Key Parakeets

Longboat Key, off Sarasota, Florida, boasts a wide variety of resident and migrant birds.  The great majority are aquatic species such as pelicans, cormorants, waders, shorebirds and ospreys.   Others include red-bellied woodpeckers, gray kingbirds, belted kingfishers and a mix of migrant warblers.  In recent decades, collared doves and black-hooded parakeets have joined the list.

Officially known as Nanday conures, black-hooded parakeets are native to eastern South America, from Brazil to Argentina.  Like other exotic species found in the U.S., they were imported for sale to zoos, collectors and private individuals and either escaped or were released into the wild.  A study conducted by the University of Florida concluded that at least 14 species of parrots and parakeets now inhabit various parts of the Sunshine State; most are found in the Miami area.  Black-hooded parakeets turned up in the Tampa Bay region over the past decade while populations of monk parakeets are now scattered …

Edge of the South

Where does the American South begin?  As a child, traveling to the Gulf Coast on summer vacations, I determined that it was somewhere beyond the Smokies and defined its presence by the sighting of palm trees or of "cranes" (my parents' name for any large wading bird) along the lakes and wetlands.  Of course, I later learned that herons, egrets and sandhill cranes inhabit much of the Continent, especially during the warmer months, and that palm trees are planted as ornamentals in many regions of our country.

Politicians and historians might focus on the Mason-Dixon Line to delineate the South but this has little relationship to our natural landscape.  One might also use a specific latitude to define the northern edge of the American South but his is problematic in the Western States where climate is more closely related to elevation than to distance from the Equator.  Defining the South as coinciding with the Coastal Plain is an attractive option; however, this geophysica…

Crossing Rivers

Heading for our condo on Longboat Key, Florida, we left Columbia this morning and drove east on I-70, undulating across the southern edge of the Glaciated Plain and crossing numerous streams that drain southward into the Missouri River.  On the outskirts of St. Louis, we crossed the Missouri itself and then the Mississippi River, just south of the Arch.

Angling southeast on I-64, we left the Mississippi floodplain and travelled across the flat, rural landscape of central Illinois, fording the wooded channel of the Kaskaskia en route.  South of Mt. Vernon, we switched to I-57 and then I-24, winding through the scenic Shawnee Hills, capped with Pennsylvanian sandstone, and eventually crossed the broad Ohio at Paducah, Kentucky.  Curving eastward, we passed over the lower Tennessee and Cumberland Rivers (just north of Land Between the Lakes) and then angled to the southeast, traveling across the karst plain of Western Kentucky, a limestone region with numerous springs and caverns but few…

Summer Kill

Most of us are very familiar with winter kill, the toll that ice storms, deep snow and severe cold take on plants, wildlife and humans as well.  This year, those of us who inhabit the Great Plains and Midwest are also dealing with summer kill, the effects of the prolonged drought and intense heat of this past year.

Today, with the "assistance" of our 5 year-old grandson, we removed a large, dead yew on the back edge of our property and I hauled its remnants to our local mulching site.  We will miss both its greenery and its role on our natural privacy fence and many of the winter songbirds that used to roost among its massive branches will certainly miss the shelter that it provided.

Compared to the hardships endured by farmers and ranchers, our loss from the heat and drought has been minimal and the death of the yew will be a minor disruption in the lives of our neighborhood wildlife.  But, when one considers the widespread effects that our scorching spring and summer had o…

The Nature of Retirement

Today will be my last at the University of Missouri and the last of my thirty-six year career as a private or employed physician.  Though I plan to participate in volunteer medical services, I will now devote most of my life to family, friends and other personal interests.

The news of one's retirement is generally greeted with a mix of reactions.  Most extend their congratulations and best wishes while some wonder aloud how the retiree can give up his or her life's work and a few hint that the decision amounts to a selfish neglect of social responsibility.  The latter reaction is more likely to be encountered by professionals than by others in society and includes the implication that special knowledge and abilities, partly achieved through government support, should not be denied to those who depend on such care.  On the other hand, many of us know physicians who attempted to extend their careers past their point of tolerance and effectiveness, endangering their own health an…

Lassen Peak

Rising just north of the Sierra Nevada Range, Lassen Peak (10,461 feet) and its cohort of volcanic domes represent the southern end of the Cascade Volcanic Arc that extends from British Columbia to northern California.  All of the well known volcanoes along this arc, and those that preceded them, have formed along a subduction zone where remnants of the Farallon Plate dip below the North American Plate.

Protected within a National Park since 1916, the Lassen Peak volcanic field contains 30 peaks in addition to smaller domes and cones.  Lassen Peak, the centerpiece of the Park, formed 27,000 years ago on the northeast flank of the Mt. Tehama caldera; the latter volcano, at least 1000 feet taller than Lassen, exploded and collapsed about 350,000 years ago.  Lassen, itself, last erupted in 1915 but remains active (as revealed by numerous fumaroles, mud pots and hot springs on its slopes).

Named for Peter Lassen, a local guide and blacksmith during the early 19th Century, Lassen Peak, lik…

Meant to Happen

One often hears the phrase "Everything happens for a reason."  Does this reflect our natural tendency to look on the bright side or is it a human defense mechanism, quelling our fear amidst the random nature of life and death.  From a naturalist's perspective, it is more the latter.

As intelligent beings, we like to think that we have control over our lives and, to a great extent, we do.  Those of us who eat well, exercise and avoid poor lifestyle choices are more likely to enjoy a long, healthy life than those who do not; in like manner, diligence, hard work and commitment are generally rewarded.  On the other hand, genetics and happenstance play a significant role in our lives; those hobbled by bad genes and those who succumb to accidents or disease beyond their control are just unfortunate victims of life's fickle nature.

Religious persons see a grand design in both the Universe and in our individual lives and believe that tragic events are part of God's plan.…

Myanmar's Earthquake

About 90 million years ago (MYA), during the Cretaceous reign of Tyrannosaurus rex, the Indian Subcontinent split from the Antarctic Plate and began to drift to the NNE.  By the end of the Cretaceous, some 65 MYA, it started to collide with the massive Eurasian Plate, a process that has lifted the Himalayas and continues today.

On the morning of November 11, a magnitude 6.8 earthquake struck north-central Myanmar.  This quake, which was followed by a magnitude 5.8 aftershock, occurred along the Sagaing Fault, where the Indian Plate is both colliding with and slipping NNE along the edge of the Eurasian Plate.  Early reports indicate widespread structural damage and at least 12 deaths; tremors from the rupture were felt as far away as Bangkok, Thailand.

While most recent earthquakes have occurred along the subduction zones of the Pacific Rim and western Indonesia, compression quakes are common across southern Eurasia where the African, Arabian and Indian Plates continue to drift northwa…

Snows in the Night

Soon after going to bed last evening, I was awakened by the distinctive calls of snow geese as they passed over Columbia.  Catching a ride on cold, northern winds behind yesterday's storm, they are headed for coastal marshlands on the Gulf Coast and will likely stop to rest and refuel along the Missouri, Arkansas or Mississippi Rivers en route.

The first snows of autumn are always an inspiring sight (or sound) and I begin watching for them during the first week of November.  Having bred and summered on the Arctic tundra, they use several staging areas on their way to southern marshlands, some of which are in Missouri; indeed, Squaw Creek NWR, on the northwest border of our State, is one of the best sites in North America to observe snow geese, which often peak from 300-500 thousand between late November and mid December.

Fortunately, those of us in central Missouri are treated to the spectacle of snow geese migrations in both late autumn and late winter (February to March).  The o…

The Nature of Heroes

General David Petraeus has become the latest American hero to fall from grace, revealing that he is, in fact, human.  Unfortunately, as a society, we love to bestow the title of hero, used to praise individuals who, despite risk to their personal safety or comfort, have demonstrated a selfless commitment to the welfare of others.

Loosely applied to a wide variety of individuals, from soldiers and firemen to teachers and social workers, the label implies superhuman dedication or accomplishment and, in a twisted way, sets them up for failure.  While we cannot excuse behavior that hurts others or places the innocent at risk, we should not be surprised to find that our heroes have their own human frailties and that many have engaged in activity that we might find offensive, if not immoral.  Indeed, those who demonstrate an excessive commitment to their career are often compensating for personal deficiencies in other areas of their life.

It is best that we praise individuals for their hero…

Escaping Brutus

Following a night of gusty winds and rattling windows, Winter Storm Brutus (so named by the Weather Channel), pushed into Metro Denver this morning, bringing much colder air and its cargo of rain, sleet and snow.  Heading east on I-70, we escaped the clouds and precipitation after crossing the Palmer Divide but the storm's powerful wind field offered additional challenges for our journey.

All across the High Plains, from Limon, Colorado, to Wakeeney, Kansas, strong southerly winds buffeted our vehicle and tossed armies of tumbleweeds across the highway; blowing dust and crop debris reduced visibility, producing a brownish haze in all directions.  The winds died down and the views broadened in central Kansas, where summer-like air, pumped northward ahead of the advancing storm, will set the stage for thunderstorms as the potent cold front invades the Heartland.

We arrived in Columbia just in time for another night of strong southerly winds.  Though we escaped the storm's assaul…

Winds of Change

For the past few days, a downsloping, southwesterly breeze has scoured the Front Range urban corridor, yielding sunny skies, warm temperatures and crystal-clear air.  Early this afternoon, a noticeable haze began to develop as a cold front dropped into Colorado, producing an upslope wind from the northeast.

This wind shift is the first sign of a significant change in our Front Range weather; while sunshine and highs in the mid 60s F prevail this afternoon, a downward slide will begin overnight.  Within 24 hours, the upslope cooling and precipitation will intensify, bringing light snow tomorrow night and highs in the 20s on Sunday.  Those of us who have lived in Metro Denver for many years come to recognize the effects of shifting winds associated with fronts; in the case of a cold front, there is a sudden coolness and haziness in the upsloping air, often scented with the aroma of feedlots to our northeast.

While it has been a pleasant week for hiking and farm work here in Littleton, t…

A Victory for Nature

The re-election of President Obama is a victory for nature, a sign that many Americans care about our natural environment and reject the claims of the Conservative Right that industrial regulations, open space protection, mass transit initiatives and a shift toward clean, renewable energy will stifle the growth of our economy.  The President's re-election also helps to insure that our country will not ignore the negative effects of pollution, habitat destruction and global warming on natural ecosystems and will foster the conviction that the welfare of human civilization is directly tied to the health of our natural environment.

The pro-business agenda of the Conservative Right, which is focused more on profits than on the environmental effects of industry has long overlooked the threats imposed by air pollution, urban sprawl, over-fishing, groundwater contamination, agricultural runoff and fossil fuel recovery in fragile ecosystems.  Granted another four-year reprieve from their …

Skittish Visitors

On this mild, sunny, crystal-clear morning, we took a walk along the South Platte River in Littleton, Colorado.  The usual mix of waterfowl and terrestrial birds were seen and a large, restless flock of Canada geese had settled on Cooley Lake.

Unlike our resident geese, which feast on our parks and golf courses and are rather tolerant of human activity, migrant flocks retain their skittish nature.  After all, in the wilds of Canada, their survival depends upon their wariness and they are quick to take flight or move to open water when predators appear.  And while our permanent residents often feed and move about in family groups or modest sized flocks, the migrants and winter visitors tend to retain their large congregations throughout the colder months.

According to the Colorado Division of Wildlife, approximately 150,000 Canada geese are permanent residents of the Front Range urban corridor.  From November into March, an additional 300,000 Canadas arrive from the north, attracted by…

Crossing High Pressure

Heading to our Littleton, Colorado, farm, we left Columbia this morning, enveloped in a steady rain.  The copious precipitation, falling through chilly air, had developed along a cold front that was pushing through Missouri.  It would not end until we reached Kansas, where a dense overcast and a gusty north wind signaled that we were now behind the front.

The strong, northerly wind, produced by a large pressure gradient between the high pressure dome to our west and the storm's low pressure to our east, raked eastern Kansas, from the Missouri border to the rust-colored grasslands of the Flint Hills.  Once we passed Salina, the winds diminished and the turbines of the Smoky Hills Wind Farm spun lazily in a light northwest breeze.  As we neared the calm center of the high pressure dome, the clouds began to dissipate and intense sunshine prevailed through most of western Kansas and eastern Colorado.  Nearing Denver, we could see clouds building behind the Continental Divide, a sign o…

Messing with Space-Time

Getting prepared for work this morning, I noticed that my favorite college football roundup was not on ESPN and, when I arrived at the hospital, the access door was locked, forcing me to buzz the security guard.  It was not until I turned on my computer that the explanation for these unexpected events became clear: it was only 5:15 in the morning.  Busy at work this week, I had been shielded from the semi-annual deluge of warnings about the seasonal time change, leading to this cascade of disorientation.  Indeed, this blog post is a product of that ignorance.

It is now clear that we have "fallen back" to standard or daylight savings time (I frankly can't remember which) and will remain there until we spring forward sometime in March or April.  Apparently designed to reduce energy consumption, this human decree has never made much sense to me; after all, we will now be turning on the lights earlier in the evening.  Then there are those regions of the country, including th…

The Bighorn Mountains

Over 200 miles in length, the Bighorn Mountains stretch from north-central Wyoming into southern Montana.  This range, which angles southeast to northwest, rises between the Bighorn Basin to its west and the Powder River Basin to the east.  The Bighorn River drains the west side of the range, cutting a scenic canyon through its northern tip on its way to join the Yellowstone River.  The famous Little Bighorn River rises on the northeast flank of the range, the Tongue River drains its central east side and the upper tributaries of the Powder River head along the southeast slopes of the range.

An outlier of the Rocky Mountain Chain, the Bighorns formed during the Laramide Orogeny, 70 million years ago, as ancient Precambrian rock crumpled upward through the overlying Paleozoic and Mesozoic sediments.  Precambrain granite is exposed along the crest of the range, which is generally 11-12,000 feet above sea level, while metamorphic Paleozoic rocks are exposed across the mid-elevation flank…

A Close Second

Coming on the heels of glorious October, the month of November is not welcomed by many of us in the Northern Hemisphere.  Though it is officially a component of autumn, November often brings the first snow of the year and represents a final slide toward the dark, cold days of winter.

Yet, this month often brings many mild, sunny days and, from the naturalist's point of view, offers some of the highlights of nature's year.  The fall waterfowl migration peaks during November, including massive congregations of snow geese and sandhill cranes.  The cooler weather and shorter days induce a restlessness in our resident birds and mammals, making them more conspicuous throughout the woodlands, prairies and wetlands.  In mid November, the Leonid meteor shower offers one of our annual astronomical highlights and, for those of us who prefer snow to rain, winter landscapes invite exploration by late in the month.

Many humans likely prefer the vibrant month of May, with its colorful flower…