Monday, December 31, 2012

Glorious End to a Tragic Year

A steady, wet snow has been falling in Columbia since early this morning and is expected to continue through most of the day.  Perfect for building a snowman, the white blanket now surrounds a dapper fellow in our front yard, constructed with the "assistance" of our grandson.

The beautiful winter scenery offers a tranquil end to an otherwise tumultuous year.  Thanks to our dysfunctional Congress, international strife, widespread social injustice (at home and abroad), an unwillingness to adequately address issues such as mental illness, gun control and global warming and an exceptional run of natural disasters, 2012 delivered more than its fair share of tragedy.

Of course, most of the problems that we face would dissolve in an atmosphere of respect, compromise and communication, traits that should define humanity.  Rather, greed, intolerance and mysticism stand in the way and the cycle of suffering continues.  Here's hoping that 2013 will bring a more enlightened approach to the welfare of human society and to the health of our natural environment.  Happy New Year to all!

Sunday, December 30, 2012

Hypertension: the Silent Killer

Hypertension, the medical term for high blood pressure, can lead to a wide range of health problems.  Unfortunately, this common condition is often asymptomatic and, unless diagnosed by routine screening, may cause end-organ damage before proper treatment is initiated.

Most individuals with high blood pressure have primary, essential hypertension, a familial condition that can be mild to severe.  If untreated, it may lead to cardiovascular disease (including coronary artery disease, myocardial infarction, congestive heart failure, stroke or peripheral vascular disease), kidney damage and visual impairment.  Secondary hypertension is blood pressure elevation resulting from another clinical condition such as kidney disease, hyperthyroidism, certain tumors, steroid excess (endogenous or exogenous), obstructive sleep apnea or drug abuse (especially the use of stimulants such as cocaine).

Fortunately, most forms of hypertension are easily treated once recognized.  Short of medication use, mild to moderate hypertension may resolve with weight loss, salt restriction, regular aerobic exercise, caffeine reduction, stress management and smoking cessation.  Of course, secondary hypertension will not resolve until the underlying condition is properly treated.  In the end, the most important step in the management of hypertension is its initial diagnosis; unless discovered early, this silent killer may produce irreversible (if not fatal) complications.

Saturday, December 29, 2012

Snowy Owls

Among the most easily identified birds on our planet, snowy owls breed on the Arctic tundra of Alaska, Canada and Eurasia.  Their dense plumage makes them the heaviest owls in North America and their wingspan may reach 5 feet.  Adult males are almost pure white with scattered, small black markings while females have black edging on their feathers; juveniles have more extensive black barring.  Snowy owls have black beaks, yellow eyes and small ear tufts that lie flat against their rounded head.

These Arctic owls feed primarily on lemmings and their population tends to fluctuate with the availability of that prey; on their breeding territory, they also hunt other small rodents and ptarmigan.  Nests are shallow depressions on the ground (usually on a low rise for visibility and dryness) and both parents cooperate in raising the young; depending upon food abundance, 3 to 12 eggs are produced.  While adults are apex predators and rarely threatened, young snowy owls are potential prey for gray wolves, arctic fox, golden eagles, skuas and gyrfalcons.

As the perpetual sunshine of the Arctic summer begins to wane, snowy owls head for wintering areas as far south as the Northern Plains and New England.  Like short-eared owls, they favor open areas, including prairie, ranchlands, broad floodplains, airports and coastal dunes and are active during the day.  Hunting from a low hill or fencepost, they may sit for hours at a time, springing into flight when prey is spotted.  Winter prey is highly variable and these owls are opportunists, taking small mammals, waterfowl, pheasant, quail, gulls and songbirds.  Veteran birders know that snowy owls are an irruptive species and look forward to their seasonal incursions; their winter population in the lower 48 varies widely from year to year and, during large irruptions, individuals have been found as far south as the Gulf Coastal Plain.

Friday, December 28, 2012

The Woodland Mouse

White-footed mice are common residents of woodlands from southeastern Canada to Mexico and throughout the eastern 2/3 of the U.S. (with the exception of Florida).  They inhabit forests, open woodlands and, on the Great Plains, riparian corridors.  Omnivorous, these mice feed on a wide variety of nuts, seeds, fruits, fungi and insects; they are agile climbers and often forage in shrubs and trees.

White-footed mice mate throughout the year and females may produce five or more litters, each with up to five young.  Nests are generally placed in hollow logs, wood piles, abandoned burrows or beneath outbuildings; old bird or squirrel nests and abandoned tree cavities may also be used.  The young are independent by one month of age and female offspring are capable of breeding within five months of birth.  Predators, including hawks, owls, fox, weasels, coyotes, skunks and snakes, serve to keep the population of these prolific rodents in check and the natural lifespan of a white-footed mice is generally less than two years.

While this mouse is a vital component of woodland ecosystems, it is known to be a vector for hantavirus and Lyme disease and close contact with the animals, their nest or their droppings should be avoided; as with all wildlife, it is best to view them from a safe and nonthreatening distance.  Since white-footed mice are primarily nocturnal, observation efforts are most productive at dawn or dusk.

Thursday, December 27, 2012

Calendar of Life

As we approach the end of the human calendar year, it seems appropriate to revisit the calendar of life.  Current scientific evidence indicates that life first evolved on Earth about 3.6 billion years ago, 10 billion years after the Big Bang and 1 billion years after the Earth, itself, formed.  If we were to condense this history of life into one human calendar year, each day would represent 10 million years, each hour would equal 417,000 years, each minute would amount to 7000 years and each second would cover 117 years.

Using this calendar of life, the first bacteria (chemoautotrophic and cyanobacteria) appear in Earth's primordial oceans at 12 AM on January 1.  By the beginning of June, eukaryotic cells (possessing intracellular nuclei and organelles) appear and, by October 15, shelled marine life and multicellular soft-bodied marine organisms (the Ediacaran fauna) inhabit the ancient seas.  Near mid November, life crawls from the sea and, throughout the last 10 days of November, sharks, boney fish, ferns, primitive amphibians, web-spinning spiders and flying insects evolve.  The first week of December brings horseshoe crabs, frogs, primitive reptiles and conifers to our planet.

Dinosaurs reign from December 8 until noon on December 25.  Crocodilians, turtles ancestral monotremes, shrew-like mammals, archaeopteryx and flowering plants all appear by mid December, followed by snakes, ants, social bees, marsupials and broadleaf trees during the third week of the month.  December 26-27 brings ancestral primates, ancestral elephants, cone snails, bats, canids, felines, rodents, early cetaceans (whales, dolphins) and ancestral horses, camels, mustelids, tapirs and sirenians (manatees and dugongs).  From December 28 into December 29, grass, ancestral pigs, mastadons and North American megafauna appear and, on December 30, giraffes, okapis, hippos, true elephants and pronghorn evolve as pinnipeds diverge from the bear line.  Cattle, bison, goats and sheep all turn up on December 31. At about 3AM on that last day, gorillas split from the hominid line and chimps do the same by 8 AM; Australopithecus appears just after noon.  Homo habilis evolves around 6 PM and Homo erectus follows by 8 PM.  During the last hour of the last day, Denisovans, Neanderthals, polar bears and arctic fox appear and humans finally grace the scene 18 minutes before midnight; no living human has been around for more than 1 second.

Wednesday, December 26, 2012

Natural History of Squid

Squid, like octopi, cuttlefish and nautilus species, are cephalopods, a branch of mollusks.  Ancestral squid, which had elongated, external shells, known as orthocones, arose in the Ordovician Period (about 500 million years ago-MYA) and their fossils appear in marine sedimentary rocks throughout the Paleozoic Era.  By the onset of the Mesozoic Era (225 MYA), belemnites, possessing a linear, internal shell, had evolved, sharing the seas with nautiloids.

As the Cenozoic Era dawned, 65 MYA, the belemnites diverged into the modern squid, octopi and cuttlefish lines; of the 800 species found today, the great majority are squid, ranging from less than 1 to almost 50 feet in length.  Like the Mesozoic belemnites, squid have an internal, chitinous "shell," known as a gladius, that supports the structure of the mantle.  Other anatomic features include a siphon for locomotion, a beaked mouth, eight arms and two long tentacles.  Squid have large, prominent eyes and those of giant squid species are the largest in the animal kingdom.  Like octopi and cuttlefish, squid have chromatophores on their external surface which allow the animal to change color and blend with its surroundings and an ink sac that releases a black cloud to confuse predators.

Squid are a diverse group of carnivorous invertebrates that occupy a wide variety of marine habitats, from warm, shallow seas to the deep, cold oceans; many deepwater species migrate toward the surface at night to feed on krill, shrimp and small fish.  The primarily predators of squid include whales, sharks, dolphins, large fish, sea birds and humans; indeed, their massive schools are an essential component of fisheries across the globe.

Tuesday, December 25, 2012

Christmas Storms

The latest winter storm system has dropped across the Southwest and, as of this morning, its central low is spinning just north of Lubbock, Texas.  Sweeping moisture in a counterclockwise direction, it is producing upslope snow across the High Plains and along the Front Range.

To its east, the potent storm is dragging copious moisture up from the Gulf of Mexico, igniting strong thunderstorms and unleashing torrential rains from eastern Texas to western Alabama.  Of special concern is the risk for tornadoes; this has developed due to the position of the low level jet stream which curves west and south of the low and then tracks across the Southeastern States.  Clashing with the southerly winds of the storm's circulation, this westerly jet is injecting energy and producing spin in the atmosphere, thus augmenting the risk of tornadic thunderstorms.

The greatest risk of tornadoes is across Louisiana and Mississippi this morning but will shift into Alabama, north Florida and Georgia later in the day.  North of these storms, a swath of ice and freezing rain is expected to impact the Ohio Valley in the coming days and the storm system will eventually bring snow to the mountains of New England.

Monday, December 24, 2012

Copahue Volcano Eruption

The Copahue Volcano, in the Andes on the border of Argentina and Chile, is erupting once again, sending a cloud of ash one mile into the atmosphere.  Chile has raised its volcano alert level to red, the highest category, but has not initiated mandatory evacuations.  Looking at photos on the internet, one wonders why they are not concerned enough to do so; beyond the volcanic ash fallout and the potential for pyroclastic flows, the mountains are covered with snow and, at the very least, flash flooding and mud flows (lahars) would seem to be significant threats.

Like all volcanoes of the Andes Range, Copahue is the product of tectonic plate subduction.  Along the west coast of South America, the Nazca Plate is being forced to dip beneath the South American Plate; this is partly due to the westward motion of the American Plates (as the Atlantic Ocean continues to open) and the eastward motion of the oceanic Nazca Plate (due to sea floor spreading along the East Pacific Rise).  As the Nazca plate dips toward the Earth's mantle, its leading edge melts, producing a chain of volcanoes above and along this melting zone.  Indeed, the entire Andes Range formed and continues to form from this subduction process.

Copahue, rising to an elevation of 9833 feet, is a stratovolcano that formed during the latter half of the Pleistocene, likely within the last 500,000 years.  This "modern" volcano, which has multiple craters, formed within the remnant caldera of a larger volcano that erupted earlier in Andean geologic history.  Though Copahue has a long history of mild to moderate eruptions (most recently in 2000), the region is a popular tourist destination due to the numerous geothermal springs that rise along its flanks.  Hopefully, the current conservative evacuation policy is devoid of economic considerations.

Sunday, December 23, 2012

The Evolution of Corals

Corals are a diverse group of marine invertebrates that first appeared in the Cambrian Period, some 550 million years ago (MYA).  Fossils of these primitive tabulate corals are found in sedimentary rocks throughout the Paleozoic Era; a second group of ancient corals, the rugose corals, arose in the Silurian (400 MYA) and both groups apparently died out during the Permian Extinction, 225 MYA.

Early Triassic rocks are devoid of coral fossils but they reappear during the mid-late Triassic, some 210 MYA.  These scleractinian corals are the ancestors of all modern corals, having undergone cycles of expansion and near extinction as well as major periods of diversification, especially during the Jurassic (150 MYA) and the Miocene (25 MYA) Periods.  It was during the latter Period that the Great Barrier Reef began to form off the northeast coast of Australia, now composed of almost 3000 reefs that harbor at least 500 species of coral.

Marine biologists have cataloged about 70,000 species of coral across the globe.  While the great majority of corals are found in shallow, clear, warm waters of tropical and subtropical seas, there are coral species that occupy deep water and cold water habitats as well.  Unfortunately, these diverse communities are significantly threatened by human activity, primarily due to pollution and the effects of global warming.  At least 10% of modern coral reefs are dead and an increasing concentration of carbon dioxide in our oceans, which acidifies the seawater, impairs the formation of calcium carbonate shells, thus threatening corals and other shell-forming marine life.

Saturday, December 22, 2012

The Northern Goshawk

The northern goshawk is the largest accipiter in North America and the most widespread accipiter on our planet, breeding in coniferous or mixed forests across northern latitudes of North America and Eurasia; various races occur across that range.  In North America, this powerful hawk is found from Alaska to Newfoundland and southward along the Cascade, Sierra Nevada and Rocky Mountain corridors; they also inhabit the Appalachian Chain as far south as West Virginia.

Favoring mature forest, goshawks typically hunt from a perch and chase down prey with a rapid, zig-zagging flight; they feed on birds and mammals, including grouse, ptarmigan, jays, woodpeckers, snowshoe hares and tree squirrels.  A bulky nest of sticks, lined with tender vegetation, is placed in a tree and vigorously defended; indeed, hikers are often assaulted by the attentive parents.  An average of 2-4 eggs are produced each year and both parents take part in feeding the young; the latter are independent by 10 weeks of age.

Northern goshawks are an irruptive species and may turn up across the Great Plains and Midwest during the winter months if prey levels fall in their native forests.  In open country, they often hunt pheasant, prairie chickens and rabbits in addition to large songbirds.  As with other irruptive species, their numbers in the Heartland vary widely from year to year.  On the other hand, despite habitat loss from logging operations, their overall population appears to be stable.

Friday, December 21, 2012

Feeding Birds

On this clear, cold morning following our first significant snowfall of the winter, I am paying close attention to our backyard sunflower feeder.  After all, the snow cover and overnight chill should send plenty of our local residents to the feeder and, perhaps, less common visitors as well.  So far, the feeding groups have included the usual mix of characters: chickadees, titmice, cardinals, white-breasted nuthatches, house finches, downy woodpeckers, juncos and white-throated sparrows; but I'll keep checking throughout the day.

Non-birders usually hang a feeder because they feel sorry for their avian neighbors, trying to survive in the cold and snow; to them, the little brown, red or gray birds are all the same.  Novice birders, on the other hand, begin to appreciate the wide variety of species that inhabit our residential areas and realize that feeders offer an effective way to attract them and to observe them at close range.  Veterans birders, of course, know that the birds would do just fine without our charity but we both enjoy their visits and hold out hope that rare winter species will be attracted by their activity.

As a longtime birder and bird feeding suburbanite, I still have mixed feelings about the use of artificial feeders and favor the use of native plant landscaping to attract wildlife.  After all, we admonish the general public not to feed the raccoons or deer or bears.  While birds do not pose the potential nuisance or danger that mammals might bring, are we not disrupting nature's cycle by this activity?  We know that feeders attract songbird predators (cats, accipiters) as well, concentrating their prey and distracting the hapless songbirds with our convenient handouts; are we not tipping the balance in the hunter's favor?  Perhaps this is all philosophical hogwash.  For now, I'll keep filling the feeder and watching for exotic visitors.  And I'll keep wondering whether I can abide my unnatural behavior.

Thursday, December 20, 2012

Tornadoes & Blizzards

As of 6 AM, the latest winter storm was centered over northwest Missouri.  Ahead of its cold front, it was 50 degrees F here in Columbia, with gusty southwest winds.  Behind the front, a blizzard was underway, stretching from Kansas City to southern Wisconsin.

Meanwhile, the counterclockwise winds of this potent winter storm were dragging Gulf moisture into the Southeast, igniting tornadic thunderstorms in southern Mississippi and Alabama.  A wedge of dry air, injected by the jet stream, pushed up the Mississippi Valley, separating the warm sector, with its heavy rain, severe thunderstorms and tornadoes, from the steady snow, cold air and brutal winds across the upper Midwest.

By 8 AM, the cold front crossed Columbia, the temperature dropped into the 30s and windblown snow filled the air.  Since the ground is warm, accumulation will be limited but steadily falling temperatures will likely produce icy roads by early afternoon.  As the storm moves to the northeast, our skies will gradually clear and an overnight low of 21 degrees F is expected.  In concert, the severe thunderstorms will push into Georgia and the Carolinas and blizzard conditions will track from the Great Lakes region into New England.

Wednesday, December 19, 2012

Humans, Empathy & Guns

Social creatures, we humans tend to be empathetic.  This trait, the capacity to recognize suffering and commiserate with those in distress, is essential to the health of our families, our communities and society as a whole.  Depending upon our personal level of comfort and capability, we are prone to offer assistance or, at the very least, to avoid comments and actions that might exacerbate their physical or emotional pain.

Unfortunately, there are some members of human society that have a limited capacity to experience empathy.  These individuals, victims of mental illness, personality disorders, post-traumatic stress disorder, organic brain pathology (tumors, strokes, dementia) or the toxic effects of certain medications and illicit drugs, may demonstrate little or no concern for the welfare of others.  Serial killers and, as we witnessed in Connecticut this week, mass murderers, generally fall into one of these categories and often feel no empathy for their victims.  Indeed, how else could one engage in such horrendous behavior?

Faced with a significant number of violence-prone, empathy-deficient individuals in our communities, it is imperative that we devote more resources toward the diagnosis and treatment of their conditions and develop effective programs to monitor and restrict their activity (including psychiatric commitment when necessary).  Friends, family members and co-workers must feel free to report their concerns to social service personnel or law enforcement authorities and mental health professionals must have the funding, manpower and legal authority to intervene.  Finally, the tools of mass murder must be removed from public access, despite the paranoid, self-righteous objections of survivalists and the gun lobby.

Tuesday, December 18, 2012

Snows over Illinois

We left Cincinnati this morning and headed west under low, gray clouds.  The overcast cleared as we crossed the Wabash River, in western Indiana, and, as we approached the broad floodplain of the Kaskaskia River, in west-cental Illinois, several flocks of snow geese shimmered in the bright blue sky.

Snow geese generally pass through the American Heartland from mid November through mid December but may linger if open water and plentiful food are available.  Those that move south through the Missouri and Mississippi Valleys used to winter only in coastal marshes, from western Louisiana to eastern Texas; in recent decades, however, they have begun to utilize croplands of the lower Mississippi Valley as well, expanding their winter range, improving their winter survival and increasing the number of geese that return to Arctic breeding grounds the following spring.  As a consequence, despite loosened hunting restrictions, their population has steadily increased and wildlife biologists are concerned that the abundant geese may threaten the health of the Arctic tundra ecosystem.

In addition to the effects of winter cropland utilization, global warming may affect the population and distribution of these vocal migrants; how it will impact their Arctic breeding habitat, the welfare of their predators, the rate of gosling survival, the timing and pattern of their migration and the extent of their winter range all remain uncertain.  For now, those of us who live in the Heartland will anticipate the sound and sight of these hardy travelers as they move across the sky in late autumn and early spring.

Monday, December 17, 2012

In Familiar Terrain

Growing up in Cincinnati, I came to know its varied neighborhoods, towns, parks and suburbs but paid little attention to its topography and hydrology.  Today, more than 40 years later, I recognize that this city, famous for its "Seven Hills," is draped across two broad ridges that rise along the Ohio River and merge north of the metropolitan area.  The Mill Creek Valley separates these uplands, receiving tributaries from both ridges; the western flank of the west ridge drains into the Great Miami River while the east slope of the eastern ridge drops into the valley of the Little Miami River.

These three major streams and their numerous creeks expose the Ordovician bedrock of Greater Cincinnati; deposited in shallow seas about 500 million years ago, the layers of shale and limestone harbor fossils of early marine life, including trilobites and bryozoans, that lived 300 million years before dinosaurs roamed our planet.  These ancient sediments remain near the surface since they overlie the Cincinnati-Kankakee Arch, a ridge of deep, Precambrian basement rock that forms the eastern rim of the Illinois Basin.

Understanding the geologic and natural history of any given region increases our appreciation of the evolutionary process and how it produced our modern landscape.  We also come to recognize the impact that humans have had on that natural landscape, highlighted in Cincinnati by the industrialized and channelized Mill Creek Valley.  Some disruption of nature is, of course, unavoidable, but, when we look beneath the veneer of roads, houses and buildings, we can still see nature's handiwork; it, in turn, inspires us to protect what remains of our natural heritage.

Sunday, December 16, 2012

Ohio's Glacial Lakes

According to the Ohio Department of Natural Resources, Ohio harbors at least 50,000 ponds and lakes and, of these, only 110 are natural.  The natural lakes are almost all glacial in origin, the product of moraine-dammed streams, glacier-scoured basins or kettle lake formation (see my post of 2-9-08) and are scattered across the Glaciated Appalachian Plateau of northeastern Ohio; a minority are oxbow lakes, which formed during meltwater floods, and are primarily found along large rivers in southern Ohio.  At the end of the Pleistocene, 10,000 years ago, there were many more glacial lakes which, in response to sedimentation and the warmer and drier climate of the Holocene, have become bogs and marshlands; others were drained by human settlers to expand their agricultural fields or to ease construction of roads and rail lines.

This weekend, while visiting family, we stayed in a cottage on Sandy Lake, southeast of Kent.  Covering 90 acres, it is 17th in size on the ODNR list of Ohio's natural lakes.  Like many other natural lakes across the country, this lake has been modified by humans; canals now connect Sandy Lake with other lakes to its north and south, ensuring an adequate water supply for nearby communities.

Though modern residential neighborhoods now encroach on Sandy Lake, it is still bordered by a wooded wetland and upland forest along its southern rim and a fine trail circles the lake, providing access to those wild areas for lakeside residents.  This weekend, flocks of Canada geese, mallards and wintering ducks settled on its calm waters, a bald eagle soared overhead, great blue herons fed in the shallows and a crescent moon reflected from a surface that, while constantly renewed, dates back to the Pleistocene.

Friday, December 14, 2012

Flat Terrain, Hidden Geology

Following I-70 eastward from central Missouri to central Ohio, as we did today, one crosses relatively flat terrain, broken only by creek and river valleys.  After all, the Pleistocene glaciers scoured the bedrock of this region and left a thick layer of glacial till as they retreated into Canada.  In Missouri, from Columbia to St. Louis, their effects were limited; as a result, the terrain is a bit more hilly and outcrops of bedrock are seen in some areas.  Columbia sits on a thick bed of Mississippian limestone which is evident at roadcuts and along stream beds throughout the city and its surrounding countryside; another prominent outcrop of bedrock is seen along the deep Loutre River valley, where a seam of Ordovician sandstone crosses the highway.

Once the traveler moves east of the Mississippi River, however, such outcrops all but disappear, primarily due to a thick layer of overlying glacial till.  While Carboniferous rocks underly I-70 throughout all of Illinois and western Indiana, narrow swaths of Devonian sediments run through Indianapolis, Indiana, and Columbus, Ohio, and the Interstate runs above Silurian bedrock through eastern Indiana and western Ohio, these basement rocks cannot be seen from the highway.  Indeed to catch a glimpse of the Paleozoic sedimentary rocks that underlie most of the Glacial Plain, one must visit deep river valleys and gorges (such as Clifton Gorge, near Springfield, Ohio).

Though geology stares us in the face across the American West, New England, the Upper Great Lakes and the Appalachian Chain, it hides beneath glacial till throughout most of the Midwest.  Of course, that till (and the rich soil that it produced) once supported a vast tallgrass prairie and now nourishes the Great American Cornbelt.

Wednesday, December 12, 2012

Evolution of Marine Animals

Life, itself, evolved in Earth's primordial oceans about 3.6 billion years ago; these initial unicellular forms of life were likely chemoautotrophic bacteria, that arose near deep ocean vents, and cyanobacteria, that evolved in warm, shallow seas.  Eukaryotic cells are thought to have developed by 2 billion years ago and, by the end of the Precambrian Era, 600 million years ago (MYA), complex, soft-bodied organisms (the Ediacaran fauna) and the first shelled marine life had evolved.

Based on fossil evidence, the diversity of shelled marine organisms exploded during the Cambrian and Ordovician Periods (550-440 MYA) and jawless fish had appeared by the end of the Ordovician; the first jawed vertebrates, including spiny fish and placoderms, appeared during the Silurian (440-400 MYA), when marine arthropods first crawled from the sea.  Primitive sharks, amphibians, lungfish and boney fish arose in the oceans of the Devonian Period (400-350 MYA), having since diversified into a vast array of species; some evolved to breed in freshwater streams while others, stranded in shallow, inland seas, became freshwater species.

Reptiles evolved from terrestrial amphibians late in the Paleozoic Era (some 300-250 MYA) and turtles appeared in the Triassic (225-190 MYA); some turtles, of course, have since returned to the sea.  In like manner, snakes evolved from lizards during the Cretaceous Period (about 70 MYA) and some became marine species. Primitive cetaceans (whales and dolphins) split from terrestrial ancestors and returned to the sea during the Eocene Period (about 50 MYA), as did sirenians (dugongs and manatees), the only marine mammalian herbivores.  Finally, pinnipeds (seals, sea lions and walruses) diverged from the bear lineage during the Miocene (25 MYA) and returned to the sea by the Pliocene (5 MYA).

Tuesday, December 11, 2012

Generation Labels

Thanks to Tom Brokaw, we all "know" that those Americans who guided us through WWII are "the Greatest Generation."  While we should not underestimate the cooperate spirit of that group, one wonders why the generation that founded our country did not earn the title.  And, with all due respect to Mr. Brokaw, what about that generation of humans that had the courage to leave Africa, some 80,000 years ago?

My own generation, often referred to as the Baby Boomers and derided by older Americans for our anti-war protests, race riots and tree-hugging tendencies, has achieved a great deal, especially in the areas of social justice and environmental protection.  Are we less patriotic for having focused on the futility of militarism, the vital importance of conservation and both the dangers and injustice of discrimination and intolerance?  Should we overlook the more prevalent racism, homophobia and careless environmental pollution of the "Greatest Generation?"

In fact, it is both misleading and inaccurate to label human generations (though that practice does sell books).  Every generation has its leaders and its followers, its producers and its consumers, its members who inspire humanity and those who tarnish our image.  Hopefully, with each generation, we become more enlightened as a species, discarding failed policies, expanding personal freedom, diminishing our impact on natural ecosystems and ensuring a better life for all segments of future generations.  If we learn to focus more on the rights and capabilities of the individual and less on the artificial divisions of human society, we will all reap the benefits.

Monday, December 10, 2012

The Muskox

Every year, when the first wave of Arctic air drops into the Heartland, I am inclined to consider those mammals that are able to thrive in such brutal conditions.  Of those that survived the Pleistocene and still inhabit the Arctic, the muskox always comes to mind.  Best known for their shaggy coats and defensive behavior, muskoxen are closely related to mountain goats and mountain sheep (as is evident from the permanent horns of both genders).

Having evolved in northern Asia, the muskox, like the woolly mammoth, crossed into North America during the Pleistocene when the Bering land bridge connected the two Continents.  While they died out in Asia and Alaska, these hardy animals survived across Arctic Canada and Greenland despite harsh conditions and determined predators (including wolves, bears and humans).  During the latter half of the 20th Century, muskox herds were successfully re-established in Russia and Alaska and others were transplanted to Scandinavia; most of these herds have been domesticated for their meat, milk and qiviut, among the finest wools on our planet.

Like American elk, muskox males gather harems during their breeding season, which occurs in August and September.  Depending upon food availability (grasses, herbs, mosses, willows), females generally breed by age three and do so every 2-3 years; a single calf is born in late spring.  While muskoxen are known to live up to 20 years in the wild, most succumb to predators, injuries or starvation at a much younger age.  When threatened, muskoxen form a defensive circle with the bulls and cows facing outward and the young in the center.

Sunday, December 9, 2012

Gray Days

A stationary front has draped itself across Missouri for the past few days, bringing classic December weather.  Separating cold air to its northwest from mild, humid air to its southeast, the front has produced chilly, damp conditions with a low, gray overcast.

Many of us likely welcome the early winter weather this year, coming as it does on the heels of an extended period of unusually warm, dry conditions that have severely exacerbated our prolonged drought.  On the other hand, few will venture outdoors in this raw weather, leaving the parks and trails for true naturalists who understand the benefits that such conditions bring.  In addition to the solitude, relished by the majority of nature-lovers, these cool, gray days stimulate our resident wildlife; mimicking the twilight of dusk, the low clouds, combined with the invigorating chill, make birds and mammals more active and, thus, more conspicuous.  Conversely, wildlife watching is generally least productive on warm, sunny afternoons.

As this front is forced to the southeast by a new, more potent cold front, the skies will clear but the temperatures will drop.  We expect an overnight low near 20 degrees F and a high tomorrow afternoon near the freezing point.  Though winter has clearly taken charge, pushing summer down to the Gulf Coast, a gradual moderation is expected through the week and, in concert, the benefits of our gray days will be lost.

Saturday, December 8, 2012

Compromise & Zealotry

Compromise is, in my opinion, the vital key to sustaining relationships, whether they be marital, political or economic.  It requires a certain degree of humility and generosity in both parties and a willingness to appreciate the other's views, needs and desires.

The enemy of compromise is zealotry, religious, political or otherwise.  Zealots, self righteous and intolerant of other points of view, live in a black and white world.  Zealotry, in turn, is fed by greed and ignorance, traits all too common in human society.

As we are currently witnessing in the U.S. Congress, infused with zealots on both the left and the right, compromise is despised and progress is stymied.  On the world stage, religious and political zealotry pose the greatest threat to peace and prosperity, fueling terrorism, intolerance, discrimination, evangelism, imperialism, dictatorships and national theocracies.  Education, communication and compromise are the antidotes.

Friday, December 7, 2012

North American Japan

The northeastern half of Japan lies on the North American Plate, which dips down from the Aleutian Chain, crosses the middle of Honshu (Japan's large central island) and then angles NNW across Siberia, west of the Kamchatka Peninsula.  The southwestern half of Japan lies on the Eurasian Plate.

Today's magnitude 7.3 earthquake, off the northeastern coast of Japan, was another subduction quake, like the massive earthquake in March, 2011, that produced the destructive tsunami; fortunately, today's quake resulted in a relatively small tsunami.  Both earthquakes occurred along a subduction zone where the Pacific Plate, moving northwest, is forced beneath the North American Plate; friction pulls the edge of the latter plate downward and, when it slips and rebounds upward, an earthquake results and displacement of the overlying sea water may cause a tsunami.  Off the southern coast of southwestern Japan, the Philippine Plate is dipping beneath the Eurasian Plate and similar subduction quakes and secondary tsunamis have and will continue to occur along that tectonic boundary as well.

It is interesting to note that the residents of northeastern Japan live on the North American Plate while those of southern California and the Baja Peninsula do not (they, in fact, live on the Pacific Plate).  Contrary to a popular assumption, the tectonic plates do not correspond to the contours of the Continents for which they are named and the Continents may be composed of land segments from multiple tectonic plates (Asia, for example, includes segments from the Eurasian, Arabian, Indian, Philippine and North American Plates).

Thursday, December 6, 2012

Pine Birds

Throughout the American Midwest, deciduous trees dominate our forests and riparian woodlands and the majority of resident birds favor those habitats.  During the colder months, however, birders may find that groves of pine and other conifers offer the best opportunity to observe visitors from the north.

Many irruptive, Canadian or mountain species, native to vast coniferous forests, favor similar habitat during their winter excursions; while most are less selective in winter, visiting mixed woodlands as well, they are usually best found in stands of conifers where their favored foods are available.  These pine-loving birds include red and white-winged crossbills, pine and evening grosbeaks, red-breasted nuthatches, golden-crowned kinglets, purple finches and pine siskins; northern saw-whet owls are also best found in dense coniferous vegetation.  While most of these species are erratic nomads, moving about in response to natural food crops, pine groves are magnets for those passing through our region.

Of course, well-stocked sunflower feeders provide another effective means of attracting these northern wanderers.  Once their attention is drawn to the feeders by mixed flocks of resident birds (cardinals, chickadees, titmice, house finches, white-breasted nuthatches and others), they join the feast and, if they like the handouts, they might stick around for a week or so.  Better yet, planting your own stand of conifers will diversify the landscape of your property and increase your chance of observing irruptive species in the future.

Wednesday, December 5, 2012

Red Wolf Controversy

When European explorers first reached North America, red wolves inhabited the southeastern quadrant of the Continent, from New England to the Ozarks of Missouri, southward to the Gulf Coast.  Smaller than gray wolves but larger than coyotes, they favored swamp forests and river valleys.  By the 1970's, habitat loss and predator control programs had eliminated them from almost all of that range and captive breeding efforts were initiated by the U.S. Fish & Wildlife Service in 1980.  The first reintroduction of red wolves occurred in eastern North Carolina, in 1987, and approximately 100 live in the wild today; a little over 200 remain in breeding centers.

Fossil discoveries have long suggested that gray wolves, red wolves and coyotes diverged from a common ancestor early in the Pleistocene (between 2 and 1 million years ago).  However, recent DNA studies revealed that 80% of the red wolf's genes are of coyote origin while 20% are from gray wolves, suggesting that red wolves are hybrids of the other two species; modern wolves and coyotes are known to hybridize with domestic canines and the geneticists theorize that red wolves arose when the natural range of gray wolves and coyotes had significant overlap, perhaps within the past few thousand years.

While this conclusion could have significant implications related to listing the red wolf as an endangered species, the U.S. Fish and Wildlife Service continues to regard that canine as a distinct species and some scientific organizations and environmental groups list the red wolf as a subspecies of the gray wolf.  Regardless of their official status, red wolves were apex predators through a large portion of North America and vital to those ecosystems before humans intervened.  In reality, hybridism plays a significant role in evolution and whether natural interspecies breeding occurred in the distant past or in more recent times should not affect our conservation efforts.  After all, non-African humans are hybrids as well, possessing a relatively small but significant contribution of genes (5%) from Neanderthals or Denisovans; see my post on 2-4-12.

Tuesday, December 4, 2012

Modern Gladiators

Few of us would condone a resurrection of the Roman Colosseum, where throngs of rabid citizens were entertained by the suffering and death of captive slaves, a tool used by the Emperors to distract the public from their own miserable lives.  We humans, after all, have evolved over the past twenty centuries and are now sensitive to both human rights and the welfare of each and every member of society.  We do what we can to protect the health of our gladiators.

Unfortunately, we humans are still entertained by public humiliation and suffering and our modern gladiators, in the form of boxers, cage fighters, hockey players and football stars, provide that service.  While medical studies continue to highlight the risk of repeated head injuries, eventually leading to traumatic dementia, we, in the interest of economics and entertainment, choose to overlook the evidence, satisfied with the preventive regulations and technologies offered by the power brokers of the sports industry.  The athletes, after all, choose to engage in their respective sport (just as soldiers, stuntmen and prostitutes accept the risks of their careers).

Like the Colosseum of ancient Rome, our modern stadiums offer a form of entertainment that many, if not most, members of society relish.  When one of the gladiators is injured and carried from the field, we stop to offer our collective thoughts and prayers; then, its back to the action, the punishing hit replayed on a giant screen for all to admire.  Meanwhile, less acute and more insidious injuries go unnoticed, at least until early dementia or suicide bring them to light.

Monday, December 3, 2012

Pascagoula River Basin

Of the many landscapes that we crossed on our trip back to Missouri from South Florida, the broad tidal marsh of the lower Pascagoula River was surely the most spectacular.  This river, the largest (by volume) unimpeded stream in the lower 48 States, rises as the Chickisawhay River, north of Meridian, and the Leaf River in the Bienville National Forest, north of Hattiesburg; its 9000 square mile watershed covers most of southeast Mississippi and a sliver of southwest Alabama and drains into the Gulf of Mexico at Pascagoula Sound.

Long utilized for its timber, water and natural food sources and more recently recognized for its spectacular diversity of plant and animal life, the Pascagoula River Basin has come under increasing protection thanks to the efforts of local environmentalists in cooperation with State agencies, the Nature Conservancy and the Audubon Society; the latter organization has established the Pascagoula River Audubon Center, in Moss Point, which introduces visitors to the rich ecosystem of the Basin, from upland oak-pine savannas, to freshwater cypress-tupelo swamps to the vast tidal wetlands along and south of Interstate 10.  A consortium of the above organizations formed the Pascagoula River Basin Alliance in 2001, devoted to the protection of the River's watershed and to the welfare of its native plants and animals, many of which are threatened or endangered.

Among the many seasonal residents of the Pascagoula Basin are brown and American white pelicans, Mississippi sandhill cranes, swallow-tailed kites, bald eagles, ospreys, American alligators and a wide variety of herons, egrets, gulls, terns and wetland songbirds.  Gulf sturgeon spawn in the river, which is also home to the endemic yellow-blotched map turtle.

Sunday, December 2, 2012

Waiting on Winter

It may be December 2 but it felt more like late September in central Missouri today. Since we just returned from South Florida, the mild conditions were gentle on the mind and body, easing us back into our life in the Temperate Zone.  Perhaps most importantly, it made the task of putting up our Christmas lights (my least favorite chore of the year), much more tolerable.

Unfortunately, as pleasant as this weather may be, our region does not need another warm, dry winter.  Coming on the heels of a prolonged drought and intense summer heat, there is hope that this season will turn the tide, bringing heavy precipitation (rain or snow...we'll take both) to revive the parched landscape and recharge our streams and reservoirs.  We're dreaming of a white Christmas, January and February!

It is thus alarming to have afternoon highs topping out near 70 degrees F as the first calendar month of winter begins; for now, the La Nina has yet to retreat. While I am not a fan of mysticism, I decided to fill our backyard feeders today; akin to stocking up on firewood, perhaps that seasonal ritual will usher in some cold, snowy weather for the Heartland.

Saturday, December 1, 2012

Traveling Blind

Those of us who love to travel look forward to seeing new landscapes, whether they are natural, rural or urban.  Some, including myself, also focus on the geology, hydrology, topography and ecology of those landscapes and often enjoy the journey as much as the destination.  We thus usually volunteer to drive and are not apt to sleep or read during road trips, unwilling to miss any interesting or unexpected sights along the way.

So I was especially disappointed this morning when our route through the southern half of Mississippi, a State in which I have spent little time, was enveloped in a pea-soup fog; for much of that segment, I saw little more than the tail lights and pavement ahead of me and, at times, the trees that lined the highway.  It was like sitting in the middle seat of an airliner when the window occupant decides to close the shade (a practice that I personally despise).  When one is blind to the journey, the act of travel looses its perspective.

Teens and young adults seem to have little interest in the experience of travel, focused as they are on their smart phones or GPS devices and generally oblivious to the environment through which they move.  Perhaps, in the distant future, when humans are transported to other locations instantaneously, the joys of travel will be lost altogether.  Unfortunately, while new technologies augment our understanding of the Universe, they tend to diminish our ties to the natural world.