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Showing posts from December, 2007

Arctic Blast

On this last day of the human calendar, the coldest air of the season is poised to drop into the Plains and Midwest. A center of low pressure, now over the eastern Dakotas, will move rapidly to the east, pulling down Arctic air in its wake; by later today, it will surely feel like winter once again.

Strong north winds will accompany this potent cold front and highs will remain in the teens or single digits across the northern tier of States. Further south, the front will produce snow flurries across Kansas, Iowa and Missouri, but the air is too dry for any significant accumulation; however, as the storm moves eastward, its strong north winds will bring heavy, lake-effect snow to the northeastern snow belt.

Here in Missouri, we will reach the middle thirties ahead of the front but the Arctic blast should arrive by late afternoon, dropping us into the upper teens overnight. Tomorrow's high is forecast to be 21 degrees F and all discussion of global warming will be put on hold!

Riverlands

Established in 1988, Riverlands Environmental Demonstration Area is north of St. Louis, just across the Mississippi River from Alton, Illinois. This 1200 acre refuge, which stretches along the west side of the River, adjacent to the Melvin Price Locks and Dam, is a mosaic of riparian woodlands, wet meadows, ponds, marsh and crop fields; entrances are off U.S. 67, in Missouri.

During the winter, huge flocks of Canada geese inhabit the preserve, joined by smaller groups of snow and white-fronted geese; trumpeter and tundra swans may also winter here. A variety of surface-feeding ducks, including mallards, green-winged teal, gadwall, wigeon, pintail and American black ducks will be found on the ponds and marshes while diving ducks and grebes favor the deeper waters behind the dam; the latter include canvasbacks, redheads, lesser scaup, buffleheads, common and hooded mergansers, ring-necked ducks, common goldeneyes and pied-billed grebes. Each year, a number of rare visitors, such as Barro…

Irruptives

Most birds adhere to predictable migration patterns, wintering and summering in specific geographic ranges. However, some birds, known as irruptives, demonstrate a fluctuating winter distribution, an adaptive response to variations in the availability of food or prey.

Perhaps the most famous irruptive in the U.S. is the snowy owl. In winters when lemming populations fall, these northern owls turn up across central latitudes of North America, attracting bird watchers from across the country. Great gray owls and boreal owls also demonstrate this pattern, though their potential range is usually restricted to more northern States.

Among songbirds, snow buntings, Bohemian waxwings, redpolls, crossbills and evening grosbeaks are the best known irruptives. Their numbers in the Heartland vary dramatically from year to year; when their northern or high country food crops are deficient (or covered by heavy snow), these erratic wanderers may suddenly appear in large flocks, providing a special…

The Florida Platform

The peninsula of Florida is the exposed, "high ground" of the Florida Platform, a broad, southward extension of the North American Plate. Stretching from southern Georgia to the Florida Strait, the Platform's east edge is just a few miles offshore at Miami and about 30 miles off the Atlantic Coast at Jacksonville; on the other hand, the west edge is 100 miles west of the peninsula's Gulf Coast.

The deep, basement rocks of the Florida Platform were originally part of northwest Africa when the Continents merged into Pangea, 250 million years ago. Then, as Pangea broke apart and the Atlantic Ocean opened, this piece of crust broke from Africa and drifted westward with the North American Plate. Initially covered by the sea, parts of the Platform began to emerge late in the Mesozoic Era as sediments accumulated on its surface and sea levels waxed and waned. Fluctuating sea levels continued through the Tertiary Period and much of the limestone in northern and central Fl…

Swamp Ghost

The possible rediscovery of ivory-billed woodpeckers in eastern Arkansas sent a wave of hope through the conservation community in 2004-2005. Yet, like reported sightings in Florida and Louisiana, the discovery remains controversial. Despite an army of observers and the use of high-tech equipment, definitive evidence of surviving ivory-bills remains elusive.

Ivory-billed woodpeckers once inhabited floodplain woodlands throughout the Southeastern U.S., from East Texas to the Carolinas. Timber production, agriculture and other human "development" decimated these old growth, swamp forests and, by the mid 1900s, the ivory-bills were thought to be extinct. While the recent events offer hope, the lessons of this story have more to do with man's impact on nature than on the possible survival of a single species.

While extinctions have occurred throughout the history of our planet, usually related to climate change or the process of natural selection, man-induced extinctions h…

Tale of Two Lows

Yesterday afternoon, a low pressure center, associated with a cold front, sat over southeastern Colorado. Its counterclockwise winds, dragging in moisture from the High Plains, produced "upslope" conditions along the Front Range, dumping up to a foot of snow in Metro Denver.

Meanwhile, an "upper level low," which formed over the Gulf of Mexico, drifted northward along the Alabama-Georgia line, bringing heavy rains to this drought-plagued region. Initially, since high pressure was parked over the eastern U.S., this disturbance was forecast to move eastward, across northern Florida. Fortunately, this "blocking high" retreated to the north and the isolated low, not associated with a front, was able to pull Gulf moisture into the drought zone. This morning, the low had moved into the mid-Atlantic region, producing beneficial rains across North Carolina and Virginia.

While most low pressure centers are associated with fronts, others develop in response to a risi…

Christmas Moon

While a "star" plays a central role in the Christmas story, it was the moon that dominated the night sky this year. Rising on Christmas Eve, the near-full moon produced shadows on the snowy landscape and was still shining brightly in the western sky early this morning.

When the moon is full, we always see the same side of its sphere; however, with all due respect to Pink Floyd, there is no permanently dark side of the moon. And, contrary to popular belief, the phases of the moon are not produced by Earth's shadow across our lone satellite; rather, they represent our changing view of its lit surface. Like the Earth, half of the moon is lit by the sun at all times (except during a lunar eclipse), but, as it orbits our planet, we see an ever-changing image of its lighted surface. Since the moon's rotation rate is synchronous with its 28-day orbit, we always see the same side of the moon when it is full and, from Earth, never see about 40% of its surface.

Like the Star of …

Postcard Morning

Walking to work this morning was like a stroll through a winter postcard. A full moon glowed in the cold, clear, western sky while Venus beamed from the southeast. A hint of dawn lightened the eastern horizon and a frosting of snow coated the ground. As if on cue, a large flock of Canada geese circled overhead, their honks breaking the silence of this early winter morning.

From man's perspective, nature is full of such beautiful scenes; after all, one usually admires his own home. But nature has many faces; beauty, grace, violence, birth, death and decay to name a few. Governed by physics and genetics, nature is focused on survival. But, conscious of our own mortality, we humans prefer to dwell on her beauty and this morning was a gem!

Great Blues over Snow

Driving through Missouri farmland this afternoon, I saw two great blue herons fly across the highway, seemingly out of place in the snow-covered landscape. Yet, a minority of these large waders, which breed throughout most of the U.S. and southern Canada, are regular winter residents across central latitudes of North America. Despite their tropical appearance, many great blues manage to survive our Midwestern winter, gathering along the larger rivers and streams, where open water is found.

During the warmer months, great blue herons feed primarily on fish, amphibians, snakes, lizards and large insects, which they stab or grasp with their long, pointed bills. Those that remain through the winter are forced to broaden that menu, often consuming field mice, shrews, crayfish, invertebrates and small birds. Why some great blues stay for the colder months rather than migrate to southern climes (like most herons and egrets), is just another mystery of our natural world; some black-crowned nig…

Solstice Storm

On this shortest day of the year, a powerful winter storm is sweeping across the Plains and Midwest. This morning, the center of the storm is over Iowa and a secondary low has formed above northern Texas. The connecting cold front separates spring-like conditions to the east from cold, dry air to its west.

The combination of high pressure over the Intermountain West and the deep low over Iowa is creating a pressure gradient that produces strong, north winds behind the front. The secondary low is dropping snow throughout the central Plains and, as the primary storm center moves into the Great Lakes Region, blizzard conditions will develop across the northern Midwest. Here in Missouri, morning temperatures in the low fifties will give way to cold, north winds by evening, with rain changing to snow; 2-3 inches are expected.

On the bright side, the winter solstice marks the darkest day of the year and, from now until June 21, the days will gradually lengthen. In concert, the solar radi…

The Milky Way

Some 1.7 billion years after the Big Bang, galaxies began to form, appearing in clusters across the expanding bubble of the Universe. Hydrogen and helium comprised 98% of this primordial matter and the fusion of these atoms within stars would produce the other elements that now comprise the building blocks of planets and, where existent, life itself.

Our home galaxy, the Milky Way, formed about 12 billion years ago, one member of a cluster that contains thirty major galaxies and many smaller ones. As galaxies go, the Milky Way is very large, harboring 600 billion stars (ten times the average); on the other hand, our galaxy cluster is quite small (the Virgo Cluster, 50 million light years away, contains 2500 galaxies). In all, the Universe is thought to contain 100 billion galaxies, many of which have collided and changed form through time; indeed, scientific evidence suggests that the Milky Way has impacted at least two other galaxies and is on a collision course with the massive Andro…

Morning Fog

Dense fog shrouded much of the Midwest this morning; the visibility in Columbia was less than a third of a mile. Extensive fog is most common during the early spring and late autumn; in the spring, it is generally due to warm, moist air settling over cold ground while, in the fall, it is usually caused by cold air interacting with warm, moist soil. In either case, the air near the ground reaches its dew point, i.e. it becomes fully saturated with water vapor, and fog develops; calm conditions or light winds favor this process while stronger winds mix the air and disrupt the saturation.

The fog will last until the surface air temperature rises above or falls below its dew point. Should the air cool, precipitation occurs and the fog dissipates; if the air warms, it expands and becomes less saturated, in which case we say that the fog has "burned off."

Today, the dense, early morning fog was associated with an air temperature of 38 degrees F. Five hours later, the temperature…

The Winter Nuthatch

Just outside our family room window is a large, deciduous magnolia, a single feeder filled with black sunflower seed and a hanging block of suet. Yesterday afternoon, the usual feeding group stopped by, composed of chickadees, titmice, white-breasted nuthatches and house finches. They were soon joined by a flicker, a small flock of pine siskins, a few cardinals and a curious group of starlings. Mourning doves, white-throated sparrows and dark-eyed juncos gathered beneath the feeder, searching for fallen seen.

While I watched this motley group, a quick movement from the periphery caught my eye and a small bird dangled from a terminal branch of the magnolia. Within a few seconds, this red-breasted nuthatch darted to the feeder, grabbed a seed and flew off. Unlike the polite chickadees, which patiently defer to larger birds at the feeder, the aggressive red-breast flew right in with each return, directing his sharp bill at any patron that challenged his appearance; only an occasiona…

December at Eagle Bluffs

On this sunny, December morning, I headed down to Eagle Bluffs Conservation Area, southwest of Columbia. Stretching along the Missouri River, most of the refuge was covered with ice and snow and a large portion remained closed for waterfowl hunting.

The preserve's largest lake, kept open by flow diverted from the Missouri, harbored a large number of ducks and coot, seemingly oblivious to the shotgun blasts in the distance. Mallards, gadwall and American coot were most common, joined by smaller flocks of shovelers and ring-necked ducks. Along the frozen shoreline, a sharp-shinned hawk dined on the remains of a duck and, off to the south, an adult bald eagle surveyed the scene from a cottonwood.

Away from the lake, noisy flocks of Canada geese roamed the refuge, horned larks scoured the ice-crusted roadways and northern harriers patrolled the snowy fields. Weedy thickets teemed with goldfinches and sparrows and the call of red-bellied woodpeckers rang through the woodlands. The h…

The Permian Extinction

Today, as global warming threatens the welfare of many species, including humans, we tend to believe that this is a unique, man-induced phenomenon. And though we are surely contributing to the process, many upheavals in Earth's climate have occurred over the past 4.6 billion years, some of which led to mass extinctions.

While the most famous is the Cretaceous-Tertiary extinction, likely caused by an asteroid strike and leading to the demise of the dinosaurs, the most severe mass extinction in the history of our planet occurred near the end of the Permian Period, 225 million years ago. The continents had merged into the giant land mass of Pangea during this Period and, by its end, the era of extensive tropical "coal forests" was fading and the climate had begun to cool. This cooling increased dramatically at the end of the Permian, likely due to massive volcanism in Siberia; altered ocean currents and a change in sea chemistry may have also played a role.

During the Permian…

Secondary Low

After blanketing Kansas and Missouri, the latest winter storm was centered over southern Illinois last evening, dropping heavy snow across the Great Lakes region. Its cold front bowed southward, across Kentucky, Tennessee and Alabama and thence southwestward over the Gulf of Mexico. A secondary low had developed along this front; centered in northern Alabama, this circulation reinforced the primary storm, pulling in copious, tropical moisture across the drought-plagued Southeast.

Producing heavy rain, thunderstorms and tornadoes throughout Georgia and the Carolinas overnight, this secondary low moved to the northeast and, this morning, is parked above the mid-Atlantic coast. Meanwhile, the primary storm has moved into northwestern Ohio and will track across northern Pennsylvania and southern New England. Pulling in warm, moist air that was injected northward by its secondary low, the storm will produce rain to the south and east of its path and heavy, wind-blown snow to its northwe…

Birding in the Snow

Conditions were not ideal for Columbia's annual Christmas Bird Count this morning. Snow had fallen through the night and the temperature at dawn was 23 degrees. Fortunately, the wind was rather light.

Experienced birders know that weather conditions can have a significant impact on birding "success." Heavy rain and high winds pose the greatest challenge, usually keeping birds in sheltered areas. Cold weather, in itself, is rarely a factor and often makes the birds more active and more visible; the effects of snow are variable, depending on the depth and rate of fall. Whenever ice or snow cover the ground, birding is generally best at feeders, near and within coniferous woodlands, along open streams or in areas where dense thickets offer food and protection.

About three inches of snow had fallen through the night and, this morning, the snowfall was light to moderate; our birding success turned out to be fairly good. As usual, starlings, grackles, red-winged blackbirds…

Our National Scavenger

Once endangered, the bald eagle has made a dramatic comeback over the past few decades and is now fairly common along the larger lakes and rivers of North America, especially during the colder months. But having survived illegal hunting and environmental poisons, our National Bird is now the victim of character assassi-nation, often labeled a scavenger that is unworthy to be the symbol of the mighty U.S. of A.

And, indeed, the majestic bald eagle is a scavenger. Though we are all impressed by its soaring flight and admire its ability to snatch a fish from the surface of a lake, we also know that bald eagles gather along rivers to feast on dead or dying salmon, follow flocks of waterfowl to take advantage of sick or injured birds and feed on the carcass of a moose or elk that has succumbed to the winter snows.

We humans are enamored with symbolism, impressed by speed, power and beauty. But nature values survival, nothing more. And bald eagles are survivors!

Christmas and Conservation

Christmas, at least in its western, secular form, is not conservation friendly. Though it was established to celebrate the birth of a man who, by all accounts, lived rather simply, it has turned out to be the holiday of consumerism.

For most Americans, conservation means the protection of endangered species, the designation of wilderness areas and the recycling of trash; but it should also refer to a lifestyle that minimizes our impact on our natural environment, limits our use of natural resources and maximizes the longevity of the products that we consume. Too often, the citizens of "developed countries" possess far more than they need and discard items (cars, appliances, houses, clothing) well before their utility is over. Unfortunately, during this season of "giving," those patterns are encouraged and exaggerated.

So, during the Christmas holidays, I often find myself in agreement with religious leaders, a group with whom I rarely concur. As they say, we woul…

The Resilient Cottontail

After denning up through the ice storm, the cottontails were out in force this morning, moving about in the predawn light. Yesterday's heavy rain and moderating temperature scoured away the hard surface glaze and opened up patches of vegetation, providing sustenance for these hardy rabbits. They will use this break in winter's wrath to feast on grasses, seeds, herbs and the buds of low shrubs, always wary of the fox, coyotes, hawks and owls that prey on them.

While many will succumb to predators, heavy snows and ice storms, more than enough will survive to replenish their population, with the first litters arriving by February. We humans, always focused on our personal turmoils, should be inspired by these resilient creatures; patience and perseverance is their motto!

Cousin Hairy

Downy woodpeckers range throughout most of the U.S. and are common in residential areas throughout the year. These small, black and white woodpeckers, often seen in pairs, are rather tame and usually feed in the company of chickadees, titmice and nuthatches.

In contrast, their larger cousin, the hairy woodpecker, is somewhat reclusive, favoring dense forest and rural woodlands. Come winter, however, they often visit residential areas, chasing downies and their cohorts from the suet block. Though their black and white markings are nearly identical to those of downy woodpeckers, hairies are significantly larger (jay-sized) and have longer, heavier bills; the males of both species have a red patch on the back of their head. Loners, hairy woodpeckers are wary birds and usually fly off if you get too close.

While he may not be neighborly, the hairy woodpecker plays a major role in the control of bark beetles and other harmful insects. If for no other reason, that service should make him welc…

The Unnatural Salton Sea

Created by faulty irrigation engineering in 1905, which triggered a 2-year flood from the Colorado River, the Salton Sea covers 376 square miles of a broad, desert basin and sits 227 feet below sea level. Once the flooding was controlled, this unnatural oasis, the largest lake in California, attracted opportunistic developers and a chain of resorts soon appeared along its shores. To bring in sportsmen, a variety of fish were introduced, most of which failed to thrive in this warm, shallow saline lake.

Receiving only 3 inches of precipitation each year, the Sea is replenished by agricultural and urban runoff from the Imperial, Mexicali and Coachella Valleys; unfortunately, this water brings salt and high-nitrogen waste into the Lake, gradually increasing its salinity (it is already more saline than sea water) and producing algal blooms. The latter result in huge fish kills and pose a secondary threat to the resident and migrant birds that feed on the Sea; American white pelicans and…

Ice Storm

As a cold front settled across Missouri last night, a series of sleet thunderstorms dropped over an inch of ice on Columbia. This morning, the front, which stretched from the Southern Plains to New England, nudged a bit to the north, producing a shallower layer of cold air in our region; the sleet gave way to freezing rain.

Though not accompanied by a powerful storm, the cold front separates dramatically different air masses. At noon, today, it was 71 in Memphis and 38 in St. Louis; Lexington was 60 degrees while Cincinnati sat at 39. It is along and near the freezing zone that the icing is most severe; further north, where the cold air mass is thick, snow is falling while, to the south, the precipitation is rain.

Ice storms pose significant travel problems for humans but are also one of the more deadly weather events for wildlife. Birds and small mammals that usually sift through leaf litter for seeds and insects find that their hunting grounds are glazed over by a thick layer of …

The Darkest Month

We are now entering the darkest month of the year, the two weeks before and after the winter solstice. During this period the Northern Hemisphere is maximally tilted away from the sun and solar radiation is least direct. The Arctic is in the heart of its perpetual winter dark-ness and, those of us at more southern latitudes, are experiencing the shortest days of the year.

While this is the darkest month, it is generally not the coldest period in the Temperate Zone. The ground is not yet frozen solid and the larger lakes remain open; as a consequence, the surface of the Earth is still radiating heat into the lower atmosphere. By mid January, this warming effect is significantly reduced and, though the days are lengthening, the coldest temperatures occur.

As darkness extends its reign, the night hunters gain an advantage; equipped with superior night vision, these predators also benefit from longer hunting periods. It is, indeed, the season of the owl and, in concert with this hunting adv…

A Weddell's Winter

Should the cold, gray Midwestern winter begin to depress you, think of the Weddell seal. This large pinniped, the southernmost mammal on the planet, spends its winter in the dark, frigid waters beneath the Antarctic ice. In order to keep from drowning, these seals must keep their breathing holes open by gnawing away the sea ice that threatens to close off their air supply; over time, this activity wears away their teeth and, though most face little threat of predation, many end up starving to death.

When not tending to its vital portholes, the Weddell seal dives for fish, squid, octopi and small invertebrates, including krill. Protected from the cold by a thick layer of blubber, this true seal is able to dive 2000 feet below the surface and remain submerged for more than an hour; a rich supply of myoglobin in its body stores and releases oxygen to its muscles and vital organs, permitting these prolonged dives. Averaging ten feet in length, Weddell seals may weigh up to 1200 pounds; fem…

First Snow

Columbia's first significant snowfall of the season began at noon today, about a month later than usual. Though only a few inches fell by evening, the snow brought a pleasing change to the drab, winter landscape.

A stationary front draped across the central Midwest throughout the day, keeping the temperature within a narrow range (29-32 degrees F) and allowing a low-pressure "disturbance" to move west to east along its track. This mobile center of lift produced a broad swath of snowfall across Missouri, with the heaviest accumulations along and north of I-70.

While the snow will drift eastward overnight, the cold air will remain entrenched and the white blanket may persist until another storm arrives over the weekend. Though the winter solstice is still a couple of weeks away, the season has now officially arrived. I'll take snow over cold rain any day!

Inland Gulls

Most Americans associate gulls with coastal beaches, seaports and, perhaps, the Great Lakes. However, gulls are fairly common inland, sometimes far from any large body of water.

California, Franklin's and ring-billed gulls are common summer residents in the Mountain and Great Basin States of the West and a variety of gulls visit the interior during the colder months. Herring and ring-billed gulls are the most common winter gulls in the Midwest, usually congregating on reservoirs or along the larger rivers; scavengers, these species also gather at landfills and restaurant parking lots. Uncommon but regular visitors include Thayer's, glaucous and black-backed gulls; these wanderers are usually seen in small numbers, mingling with their more common cousins.

Some of the best places to see a variety of winter gulls are the major dams along the Mississippi and Missouri rivers. There, the gulls usually gather beneath the dam, snatching fish that are stunned by the turbulent flow. This …

Mattamuskeet

While almost all wildlife refuges are interesting throughout the year, some were established for specific, seasonal reasons and, thus, are especially rewarding during those months. Mattamuskeet National Wildlife Refuge, in eastern North Carolina, provides an excellent example.

Established in 1934 to protect wetland habitat for migrant and wintering waterfowl, this Refuge, centered on the State's largest natural lake, attracts huge flocks of geese, ducks and tundra swans from late autumn through early spring. The preserve is a mosaic of crop fields, marsh, cypress swamps, pine-hardwood forest and the shallow, 40,000-acre lake. Tundra swans are certainly the highlight for most birders; after a summer in the Arctic, an average of 30,000 swans winter at Mattamuskeet. Canada geese, snow geese, Ross' geese, white-fronted geese and a large variety of ducks also rest and feed at the refuge, patrolled by bald eagles and peregrine falcons that move south with these flocks. Resident mamma…

The Wildlife Advantage

In dealing with the harsh conditions of winter, wild creatures have a definite advantage (both mentally and physically) over we humans. Equipped with thick pelts or insulating feathers, they remain active, searching for the prey, edible plants or carrion that they need to stay alive. Unlike their human counterparts, they neither anticipate nor experience the regular shift from heated to unheated environments and thus (one would assume) barely notice the gradual change in temperature that occurs throughout the day and night.

Unhampered by technology, they are neither bombarded by dire weather forecasts nor reminded of the wind chill several times each day. Since they do not consult thermometers, they, unlike data-conscious humans, are likely unaware of the difference between 18 and 28 degrees F. We, on the other hand, often let the weather rule our lives or, at the very least, use it as an excuse to put off unpleasant chores. Besides, we have a warm house to retreat to!

Thunder in December

While we usually associate thunderstorms with warm seasons and warm climates, they can occur at any time of year. In fact, snow thunderstorms are not at all uncommon.

As the recent winter storm pulled away to the northeast, a warm, southerly flow developed; yesterday, after a wet and chilly morning, the temperature rose through the day and, by late evening, we were in the mid fifties. The balmy flow continued through the night and, this morning, we awoke to sixty degrees in central Missouri; however, dark clouds on the western horizon foretold a coming change. A strong Alberta Clipper would soon end our December respite.

Sure enough, thunderstorms developed by 10 AM, dropping torrential rains; within two hours, the temperature had dropped from sixty to thirty-eight and strong, northwest winds made it seem even colder. Following a night in the fifties, tonight's low is forecast to be 23. That should bring us back to reality!

Winter Storm

After forming off the coast of Southern California and bringing much needed rain to the Desert Southwest, the first major winter storm of the season is dumping heavy snow in the southern Rockies and will move across the Northern Plains today. Icy conditions will prevail in western Kansas, southern Nebraska and northern Missouri, with significant snowfall to the north of that swath. Southward, steady rains will drench the Central Plains and lower Midwest.

Tomorrow, the storm will move across the Great Lakes and into the Northeast, bringing a mix of ice and snow to that region. Finally, gaining strength off the New England Coast, it is forecast to dump heavy snow on the Northern Appalachians.

Contrary to popular perception, such storms are not a massive swirl of moisture that drains itself as it moves across the country. Rather, the storm is a low pressure center (and its associated cold front) that pulls in moisture from the south and forces it to collide with or override cold air to…