So far, it's been a mild, snowless winter for much of the U.S. and many ski resorts, from California to Maine are desperate for a return to more typical conditions. But while the economic hardship imposed on these communities is of concern, a lack of sufficient snowpack to feed metropolitan reservoirs poses a more significant threat. This is especially true across the American West, where mountain snowfall is the primary source of water for public consumption, industry and agriculture; the dearth of snow in the Sierra Nevada is of particular concern in light of the massive population that resides across the semiarid landscape of Southern California.
The primary culprit for this snow drought appears to be the La Nina weather pattern, characterized by high pressure over the eastern Pacific. In such years, Pacific storms are shunted to the north and onshore moisture flow is shut off along the California coast; some of these storms end up dropping southward through the Rockies (as is occurring today) providing some relief to that region. Indeed, so far this winter, the few significant cold fronts that have invaded the U.S. have plunged from Canada into the Heartland, unaccompanied by Pacific moisture. Some of these atmospheric troughs have ignited snowstorms across the Southwest and Southern Plains as moisture streamed in from the Baja and Gulf of Mexico but the Northern Plains have remained high and dry.
Some climatologists also point to lower atmospheric pressures over the North Atlantic, favoring a mild, southwesterly flow across the Lower 48. Whatever the cause for our warm and snowless winter, it is not likely related to global climate change; one need only recall the severe cold and heavy snows of last winter to realize that our current dilemma does not necessarily represent a developing trend. In fact, current seasonal forecasts, to the extent that they are accurate, predict a return to more typical winter conditions for the remainder of the season. As always, time will tell.
Sabtu, 07 Januari 2012
Jumat, 06 Januari 2012
The Raton Basin
Driving along I-25 between Walsenburg, Colorado, and Raton, New Mexico, one enjoys spectacular scenery, including lofty peaks, high mesas and rugged canyons. One would certainly not imagine that this area was once a basin!
Yet, back in the Cretaceous, some 100 million years ago, when Tyrannosaurus rex and his cohorts roamed the planet and a broad seaway stretched from Texas to western Canada, a geologic basin extended across this region, tilted upward to the west; marine shale, known as Pierre Shale, covered the floor of the basin, deposited by the Cretaceous Sea. As the Rockies began to rise and the sea retreated to the south and east, coastal sands settled on the shale and have since hardened into the sandstone of the Trinidad Formation. Then, toward the end of the Cretaceous, a delta ecosystem spread across the region, destined to yield the shales, siltstones, sandstones and coal seams of the Vermejo Formation; coal has been mined from this formation since the 1800s and methane has been retrieved since the 1980s. As the Cretaceous gave way to the Tertiary Period, alluvial debris from the rising mountains covered the area, the source of conglomerates that now comprise the Raton Formation; harboring pockets of coal, this Formation is famous for its exposure of the K-T boundary, within which a high level of iridium supports the theory that a catastrophic meteor impact ended the Cretaceous and wiped out the dinosaurs. Finally, during the Paleocene, alluvial sands and muds of what is now the Poison Canyon Formation covered any remaining evidence of the underlying geologic basin.
Since then, in concert with continued uplift along the Rocky Mountain corridor, granite intrusions pushed up into the sediments, later to be uncovered by erosion to reveal the spectacular Spanish Peaks of southern Colorado, complete with Eocene-Oligocene lava dikes that formed as these massive plutons rose. In the late Miocene, about 9 million years ago, the Raton-Clayton Volcanic Field developed across northeast New Mexico, spreading thick pools of basalt across what is now the Colorado-New Mexico line. This hard cap of basalt protected the underlying Tertiary and Cretaceous sediments, yielding a chain of high mesas that stretch from the base of the Rockies to the Oklahoma Panhandle, separating the watersheds of the Arkansas and Cimarron Rivers.
Yet, back in the Cretaceous, some 100 million years ago, when Tyrannosaurus rex and his cohorts roamed the planet and a broad seaway stretched from Texas to western Canada, a geologic basin extended across this region, tilted upward to the west; marine shale, known as Pierre Shale, covered the floor of the basin, deposited by the Cretaceous Sea. As the Rockies began to rise and the sea retreated to the south and east, coastal sands settled on the shale and have since hardened into the sandstone of the Trinidad Formation. Then, toward the end of the Cretaceous, a delta ecosystem spread across the region, destined to yield the shales, siltstones, sandstones and coal seams of the Vermejo Formation; coal has been mined from this formation since the 1800s and methane has been retrieved since the 1980s. As the Cretaceous gave way to the Tertiary Period, alluvial debris from the rising mountains covered the area, the source of conglomerates that now comprise the Raton Formation; harboring pockets of coal, this Formation is famous for its exposure of the K-T boundary, within which a high level of iridium supports the theory that a catastrophic meteor impact ended the Cretaceous and wiped out the dinosaurs. Finally, during the Paleocene, alluvial sands and muds of what is now the Poison Canyon Formation covered any remaining evidence of the underlying geologic basin.
Since then, in concert with continued uplift along the Rocky Mountain corridor, granite intrusions pushed up into the sediments, later to be uncovered by erosion to reveal the spectacular Spanish Peaks of southern Colorado, complete with Eocene-Oligocene lava dikes that formed as these massive plutons rose. In the late Miocene, about 9 million years ago, the Raton-Clayton Volcanic Field developed across northeast New Mexico, spreading thick pools of basalt across what is now the Colorado-New Mexico line. This hard cap of basalt protected the underlying Tertiary and Cretaceous sediments, yielding a chain of high mesas that stretch from the base of the Rockies to the Oklahoma Panhandle, separating the watersheds of the Arkansas and Cimarron Rivers.
Kamis, 05 Januari 2012
The Arctic Falcon
Gyrfalcons are the largest and most powerful falcons on our planet, inhabiting Arctic and Subarctic regions of the globe. Those that live near or above the Arctic Circle are white or pale gray in color while more southern subspecies have various degrees of gray or brown in their plumage.
Solitary for much of the year, adult males and females pair up in March and a clutch of eggs is laid by late April, usually on a bare rock ledge or perhaps in an abandoned raven nest. Both parents incubate the eggs and, within two weeks of hatching, the downy young are left to endure the harsh northern climate while the parents hunt for food; it is then that gyrfalcons are most vulnerable to predation, usually by ravens, skuas or Arctic fox. Those that survive to adulthood have little to fear from natural predators; swift, powerful and agile, they are imposing rivals and may live for 20 years or more.
Gyrfalcons feed primarily on ptarmigan but also attack geese, ducks, gulls and a variety of Arctic songbirds; tundra residents such as Arctic hares, ground squirrels and lemmings are also potential victims. These magnificent raptors, in the style of great white sharks, initially stun their prey with a traumatic collision or chase them to ground before making the kill. During the colder months, gyrfalcons are known to hunt along the pack ice, oblivious to the frigid conditions; though nonmigratory, a few may turn up across the northernmost U.S. in mid to late winter.
Solitary for much of the year, adult males and females pair up in March and a clutch of eggs is laid by late April, usually on a bare rock ledge or perhaps in an abandoned raven nest. Both parents incubate the eggs and, within two weeks of hatching, the downy young are left to endure the harsh northern climate while the parents hunt for food; it is then that gyrfalcons are most vulnerable to predation, usually by ravens, skuas or Arctic fox. Those that survive to adulthood have little to fear from natural predators; swift, powerful and agile, they are imposing rivals and may live for 20 years or more.
Gyrfalcons feed primarily on ptarmigan but also attack geese, ducks, gulls and a variety of Arctic songbirds; tundra residents such as Arctic hares, ground squirrels and lemmings are also potential victims. These magnificent raptors, in the style of great white sharks, initially stun their prey with a traumatic collision or chase them to ground before making the kill. During the colder months, gyrfalcons are known to hunt along the pack ice, oblivious to the frigid conditions; though nonmigratory, a few may turn up across the northernmost U.S. in mid to late winter.
Rabu, 04 Januari 2012
Musk Hogs
Collared peccaries, otherwise known as javelinas or by their more colorful title of musk hogs, are native pig-like residents of the Sonoran and Chihuahuan Deserts of the Southwest U.S., from southern Arizona to southwest Texas. They and other peccary species are also found southward through Mexico, Central American and most of South America. All are descendents of a Eurasian ancestor that split from the common pig lineage back in the Eocene, some 50 million years ago.
Living in herds of up to 50 individuals (10-20 is typical), collared peccaries roam the canyons and arroyos of the Desert Southwest, under the control of a dominant male. He breeds with females in the group throughout the year and pregnant females temporarily leave the herd to deliver their young (usually 2) in a den or hollow log. Older sisters help to raise their new siblings and newborn females are sexually mature within a year.
Thinner and longer-legged than common pigs, collared peccaries have a coarse coat of gray-brown hair with a darker mane down their back and a lighter ring around their neck; while their eyesight is rather poor, these desert residents have a keen sense of smell. Short, sharp tusks offer some protection from predators (mountain lions, coyotes, bobcats) but their aggressive nature and group mentality provide their best defence. Omnivorous, peccaries feed on a variety of plant materials (prickly pear cactus and agaves are favored) but also consume eggs, reptiles and carrion; avoiding the heat of mid-day, they usually forage in the early morning and evening hours. The name "musk hog" is derived from the potent musk gland on their upper rump which they use to mark their territory and one another.
Living in herds of up to 50 individuals (10-20 is typical), collared peccaries roam the canyons and arroyos of the Desert Southwest, under the control of a dominant male. He breeds with females in the group throughout the year and pregnant females temporarily leave the herd to deliver their young (usually 2) in a den or hollow log. Older sisters help to raise their new siblings and newborn females are sexually mature within a year.
Thinner and longer-legged than common pigs, collared peccaries have a coarse coat of gray-brown hair with a darker mane down their back and a lighter ring around their neck; while their eyesight is rather poor, these desert residents have a keen sense of smell. Short, sharp tusks offer some protection from predators (mountain lions, coyotes, bobcats) but their aggressive nature and group mentality provide their best defence. Omnivorous, peccaries feed on a variety of plant materials (prickly pear cactus and agaves are favored) but also consume eggs, reptiles and carrion; avoiding the heat of mid-day, they usually forage in the early morning and evening hours. The name "musk hog" is derived from the potent musk gland on their upper rump which they use to mark their territory and one another.
Selasa, 03 Januari 2012
Dam Birding
The contruction of dams across this country (and around the globe) has produced a variety of positive and negative effects. On the positive side, dams have been used to prevent flooding, provide a steady supply of water, produce electricity and create lakes for recreational activities such as fishing and boating. Negative effects have included the destruction of natural wetlands and swamp forests, the flooding of canyons and, though often unrecognized, the false security of placing residential and commercial developments on floodplains.
Here in the American Heartland, dams offer another advantage, especially during the winter months. By creating adjacent pools of deep and turbulent water, they yield open feeding areas for a wide variety of birds amidst a cold, frozen landscape. Large flocks of waterfowl often gather behind the dam, including divers such as mergansers, scoters and loons. Below the dam, where fish are stunned by the turbulence, bald eagles, great blue herons and a variety of gulls gather to glean prey from the surface; the common ring-billed and herring gulls are often joined by rare northern species that funnel southward as more northern waterways freeze over.
Of course, these dams also attract a variety of migrants during the spring and fall migrations, when flocks of black and least terns, Franklin's and Bonaparte's gulls, red-breasted mergansers, common loons, Mississippi kites, herons, egrets, white-faced ibis, cormorants and a host of swallows take advantage of fish and insects that congregate near and along these concrete barriers. Despite their negative impact on river ecosystems, dams can offer some damn good birding!
Here in the American Heartland, dams offer another advantage, especially during the winter months. By creating adjacent pools of deep and turbulent water, they yield open feeding areas for a wide variety of birds amidst a cold, frozen landscape. Large flocks of waterfowl often gather behind the dam, including divers such as mergansers, scoters and loons. Below the dam, where fish are stunned by the turbulence, bald eagles, great blue herons and a variety of gulls gather to glean prey from the surface; the common ring-billed and herring gulls are often joined by rare northern species that funnel southward as more northern waterways freeze over.
Of course, these dams also attract a variety of migrants during the spring and fall migrations, when flocks of black and least terns, Franklin's and Bonaparte's gulls, red-breasted mergansers, common loons, Mississippi kites, herons, egrets, white-faced ibis, cormorants and a host of swallows take advantage of fish and insects that congregate near and along these concrete barriers. Despite their negative impact on river ecosystems, dams can offer some damn good birding!
Senin, 02 Januari 2012
The Arrogance of Certainty
As intelligent creatures, we humans are prone to the arrogance of certainty. We convince ourselves that we completely understand other individuals, other cultures or the field of study in which we have personal experience. Of course, this is rarely, if ever, the case and our assumption leads to personal, domestic, societal or even international conflict.
The long and ongoing battle between science and religion highlights this human trait. Religious zealots often point to the wealth of scientific theories which, in later times, proved to be inaccurate. Yet, this is the nature of science, defined by its sequence from theory to experimentation to conclusion. Furthermore, science has advanced, and will continue to advance, by remaining open to new theories that challenge established doctrine; new data is welcome, whether it supports traditional concepts or redirects our point of view. Religion, on the other hand, based on a belief system that discourages investigation and condemns doubt, is protected by rigid dogma; in the world of the true believer, proof is neither necessary nor desired.
While religion highlights our tendency to be self-righteous, it has plenty of company in the political arena, as the current Republican primary candidates so clearly demonstrate; the invasion of Iraq was, after all, based on the false conviction that Sadam had nuclear weapons. Human society would do well to trade in our arrogance of certainty for a more open-minded and cooperative approach to our many problems.
The long and ongoing battle between science and religion highlights this human trait. Religious zealots often point to the wealth of scientific theories which, in later times, proved to be inaccurate. Yet, this is the nature of science, defined by its sequence from theory to experimentation to conclusion. Furthermore, science has advanced, and will continue to advance, by remaining open to new theories that challenge established doctrine; new data is welcome, whether it supports traditional concepts or redirects our point of view. Religion, on the other hand, based on a belief system that discourages investigation and condemns doubt, is protected by rigid dogma; in the world of the true believer, proof is neither necessary nor desired.
While religion highlights our tendency to be self-righteous, it has plenty of company in the political arena, as the current Republican primary candidates so clearly demonstrate; the invasion of Iraq was, after all, based on the false conviction that Sadam had nuclear weapons. Human society would do well to trade in our arrogance of certainty for a more open-minded and cooperative approach to our many problems.
Minggu, 01 Januari 2012
The New Year Roars In
No longer keen on late night parties, my wife and I have not witnessed the arrival of a New Year for quite some time. Last evening, however, at the stroke of midnight, I was awakened from sleep, not by the sound of firecrackers but by the rattling of windows and the roar of wind through the barren trees.
After a few days of spring-like weather, a cold front pushed through central Missouri as 2011 gave way to 2012. The balmy conditions of last evening, including the day's high of 61 degrees F, were suddenly retreating to the south as strong, northwest winds dove in behind the front. Not yet subsiding, they have dropped our temperature by 20 degrees and are producing both a wind chill in the teens and a reality check for those of us in the Midwest.
No doubt, some saw a message in that midnight front, an omen of danger for the coming year. But, while the winds arrived in concert with the calendar shift, the calendar itself is an arbitrary creation of human culture, not directly associated with natural events and requiring adjustment every four years. From a naturalist's point of view, the front arrived about nine and a half days after the winter solstice, the true start of nature's year.
After a few days of spring-like weather, a cold front pushed through central Missouri as 2011 gave way to 2012. The balmy conditions of last evening, including the day's high of 61 degrees F, were suddenly retreating to the south as strong, northwest winds dove in behind the front. Not yet subsiding, they have dropped our temperature by 20 degrees and are producing both a wind chill in the teens and a reality check for those of us in the Midwest.
No doubt, some saw a message in that midnight front, an omen of danger for the coming year. But, while the winds arrived in concert with the calendar shift, the calendar itself is an arbitrary creation of human culture, not directly associated with natural events and requiring adjustment every four years. From a naturalist's point of view, the front arrived about nine and a half days after the winter solstice, the true start of nature's year.
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