Rosy Finches in Colorado

Rosy finches are medium-sized songbirds of the American West that are among the most prized and most elusive quarry of avid birdwatchers. Since they nest at higher elevations than all other North American birds, rosy finches are especially difficult to observe during the warmer months. Come winter, they form large, mixed flocks and often appear in mountain towns and at ski resorts, where they feast on human handouts; during periods of heavy snow, some flocks descend to lower elevations, roosting in the crevices of rock-walled canyons.

Of the three rosy finches in North America, only the brown-capped species breeds in the mountains of Colorado; indeed, one of the best places in North America to observe this finch is at Summit Lake, along the Mt. Evans road, west of Denver. Gray-crowned rosy finches breed in mountains of the Pacific Northwest while black rosy finches summer in the high mountains of northern Utah, western Wyoming, Idaho and western Montana. Generally nesting on cliffs near open tundra, rosy finches feed on the ground, scouring alpine grasslands and snowfields for windblown seed.

During winter and early spring, all three species inhabit the high country of Colorado and, as above, are best found in mountain towns or at ski resorts; feeders at the Loveland Basin Ski Resort (at the east entrance to the Eisenhower Tunnel, on I-70) provide one of the better sites to find them close to Denver. Should severe winter weather envelop the mountains, these hardy but erratic wanderers may descend to the foothills, turning up in towns such as Estes Park, Morrison (Red Rocks Park), Woodland Park and La Vita.

Lone Stranger

Though more common during the warmer months, rufous-sided towhees can be found in the Midwest throughout the year. But even in summer, these reclusive birds are not terribly common in residential areas. Favoring brushy slopes and wood margins, they scratch for insects and seeds beneath thickets, shrubs and cedar groves.

This past week, which was characterized by frigid temperatures and extensive snow cover, a lone towhee turned up at our backyard feeder. Joining the usual assortment of suburban "feeder birds," the towhee would huddle in the sun on a nearby branch and intermittently drop beneath the feeder to feast on fallen seed; I'm sure he also took advantage of various wild berries along our wood border.

While I have seen rufuous-sided towhees on numerous occasions and have observed them in abundance across the Front Range foothills, to host this single bird, somewhat out of place among the standard cast of winter visitors, has been a special treat during an otherwise brutal week. Such events are among the special joys of having a backyard feeder; uncommon visitors or transients, attracted by the commotion of the usual suspects, make a grand appearance. Indeed, many bird watchers, including most novice birders, have found new species (for their life or backyard list) in this way.

Weather, Climate & Conservation

As severe cold has enveloped much of the Northern Hemisphere over the past few weeks, concerns about global warming have certainly been upstaged by worries related to crop damage, travel disruption and frozen pipes. Of course, temporary weather patterns have little to do with the long term climate change and global warming always receives more attention in the midst of a long, hot summer.

While there is little doubt that Earth's climate is warming and that man has played some role in the process, the welfare of natural ecosystems and of the human species is threatened by a host of factors, not all of which are under our control. Earthquakes, volcanic eruptions, tidal waves, hurricanes and other severe weather events will surely have more impact in the coming decades than the gradual change in climate and how global warming will affect weather patterns and agriculture is still open to speculation.

On the other hand, we must acknowledge the multiple negative impacts that we have on Earth's ecosystems and make every effort to minimize them. While attention to carbon emissions is certainly important, we cannot overlook the many other forms of pollution that result from human activity. And while technology and recycling may solve some of our problems, the willingness to address excess consumption, habitat destruction and uncontrolled population growth will be vital to the future welfare of our planet and our species.

The Nadir

With the center of this Arctic outbreak parked over northwest Missouri, it is likely that we have now endured the coldest air of this system and, very possibly, the lowest temperature of this winter season. As I walked to work this morning, a crescent moon beamed in the clear, dark, southeast sky; it was nine degrees below zero (F) and this afternoon's high is forecast to reach ten above.

But, after a slightly less chilly night, we should be on the backside of the Arctic dome by tomorrow and southwest winds will push us into the mid twenties; on the negative side, these winds will produce a wind chill that might make it feel colder than it does today. Thawing should begin by mid week as the frigid air moves off to the east and we return to more seasonable conditions; by then, the upper thirties will feel like spring.

Prolonged, severe cold can have a depressing effect on humans, not designed to function in such weather. But native wildlife, not focused on thermometers and weather reports, took the polar air in stride. No doubt, some creatures succumbed to the brutal conditions but, for them, every day is a life and death struggle.

Fault-block Mountains

Most of Earth's mountain ranges have formed due to compression within or along tectonic plates and many others are volcanic in nature, having developed above a mantle plume or along subduction zones. A third type of orogeny, fault-block mountains, rise along faults where the crust is under tension; this stretching generally occurs between areas of uplift or due to friction with other tectonic plates (often distant from the rift zone). As the crust is stretched, fault lines (some new and others old) rupture perpendicular to the line of stress and one edge of the crust slips above the other; as a consequence, fault-block mountains have a steep face along the fault and a gentler slope on their other side.

In the U.S., fault-block mountains are most common across the Great Basin, in the desert Southwest and along the Rio Grande Valley. In the Great Basin, topographic waves of these fault-block ranges, running north to south and spaced east to west, rise above high, flat desert and scrublands between the Wasatch Plateau of Utah and the Sierra Nevada of California. Among our more well known fault-block ranges are the Tetons of Wyoming (their steep edge facing east) and the Sandia Mountains east of Albuquerque, New Mexico (their steep edge facing west).

Though difficult to appreciate during our brief life span, most of these fault-block ranges continue to rise as the rifting process persists. Earthquakes are common along and near these mountains and, eventually, those of the Southwest and Great Basin are expected to become islands as ocean waters invade from the Sea of Cortez.

Advantage: Predators

In the course of nature's year, there is a shifting balance between predator and prey. During the colder months, when food is scarce and heavy snows or ice impair mobility, the hunters have a decided advantage.

Across the north, wolf packs feast on elk, moose and deer that are weakened by the elements and stranded by the weather. In more moderate climes, owls, hawks, coyotes and fox enjoy a similar advantage; though their prey (cottontails, voles, quail) may den up during severe weather, they must eventually seek food and, when they do, these patient and well-equipped hunters are waiting. Flocking birds, especially gregarious during the winter months, are easy targets for falcons and accipiters.

Winter is, indeed, the culling season, ensuring that prey populations remain in check. And, despite the brutal conditions, it is often a less challenging season for many of the predators. But spring will arrive, greenery will spread, new generations of prey will appear and their populations will soar; then, it will be their season in the sun.

Frigid Sunshine

Looking out from our heated homes, it has been beautiful in central Missouri over the past few days. Bright sunshine, clear blue skies and a snowy landscape have produced an appealing winter scene. But outside, the beauty has come with a price: cold, dry air with temperatures in the teens and single digits.

In mid winter, the sun angle is too low to provide much heat and the clear skies, devoid of cloud cover, allow what little heat is present to escape into the upper atmosphere. Of course, this process is compounded on clear, winter nights and our overnight lows have dropped below zero F.

By tomorrow, southwest winds, ahead of the next Arctic front, will bring in clouds and snow; this combination of a southerly flow and a cloud blanket should allow our afternoon temperatures to soar into the low to mid twenties. Unfortunately, the second round of polar air, due by late in the week, will bring the coldest days and nights of the season. At least the sunshine will warm our souls.

The Nature of Hypothermia

Like birds and other mammals, humans are endotherms; our core body temperature is independent of our environment and, in order for our organ systems to function properly, it must be maintained within a rather narrow range. Heat generation is through shivering, other muscular activity and our internal metabolism. Ninety percent of our heat loss is through the skin (sweating, radiation, conduction, convection)while 10% is via the lungs; heat loss via conduction increases dramatically with water immersion and convectional heat loss is augmented by wind. If supplied with adequate food, water and shelter, a naked human adult can maintain a normal core temperature in environments ranging from 55 to 130 degrees F; beyond this range, our compensatory mechanisms are inadequate and we become hypothermic or hyperthermic (both potentially fatal conditions).

As the present wave of Arctic air spreads across much of our country, some humans, tropical creatures that we are, will die of hypothermia; risk factors include advanced age, exposure to the environment, general debilitation, malnutrition, injury, substance abuse, poverty, chronic medical illness and certain medications. As mild hypothermia develops, peripheral vasoconstriction shunts blood to the vital organs, kidney perfusion increases, urine formation increases (known as cold diuresis), blood volume falls and our heart rate increases; shivering develops and we increase our metabolic rate to generate heat. As hypothermia progresses, the shivering reflex is lost, our heart rate slows, blood pressure falls and blood flow to our brain decreases, leading to confusion and paradoxical undressing. Severe hypothermia results in coma, depressed ventilation and, eventually, death (usually from ventricular arrhythmias or asystole).

Prevention of hypothermia includes the avoidance of unnecessary exposure, intake of high-caloric food, adequate hydration and the use of warm, layered clothing (including efforts to minimize heat loss from the head and extremities); layers should be adjusted to prevent sweating, which accelerates heat loss. Use of alcohol, which promotes peripheral dilation and augments heat loss, must be avoided. Persons found to be hypothermic should be warmed with multiple blankets (after removal of wet clothing) and should not be moved any more than is absolutely necessary (movement may trigger lethal arrhythmias in a hypothermic heart). Emergency medical assistance should be sought as soon as possible and CPR should be initiated if vital signs are lost; it is important to keep in mind that some individuals with extreme hypothermia have been successfully resuscitated, often with minimal neurologic sequelae (the record low core temperature for a surviving adult is 60.8 F or 16 C).

Subtle Beauty

Male cardinals get a great deal of attention during the winter months, when their bright red plumage contrasts with barren woodlands and snowy landscapes. Indeed, these "red birds" are among the best known and favored species of the casual backyard birder.

But, from my point of view, their less glamorous partners are more attractive. Though their colors are not as bright and eye-catching, female cardinals have a beautiful, varied plumage of muted, natural tones. Dull, reddish highlights on their crests, wings and tails contrast with their soft brown back and lighter, buff colored chest and abdomen. A black facial mask, not as dark and sharp-edged as that in the male, sets off the heavy, pink-orange bill that typifies all cardinals.

As one known for a rather dull-colored wardrobe of greens and browns, I readily admit to my preference for earth tones; "loud" clothing has never appealed to me. Perhaps I'm just programmed to appreciate the more subtle beauty in nature as well.

Midwest Sink

Some cold fronts sweep into the Midwest behind potent storm systems, as strong, northwest winds develop behind an energized low; in these cases, destructive thunderstorms often precede the front while heavy snow and blizzard conditions develop to its west. Other cold fronts, usually dropping south from the Canadian Plains, arrive with barely a whimper as dense, frigid Arctic air flows through the Heartland like a slow, broad river. Often nudged from the North Pole by a developing ridge over Alaska and western Canada, the dome of cold, dry air funnels southward between the High Plains and the Appalachians, with the most frigid air settling across the Upper Midwest.

Record low temperatures had developed across Minnesota and the eastern Dakotas this morning (as the center of the dome crossed into the U.S.) and extreme cold is forecast for most of the Midwest throughout the coming week; the leading edge of the cold air, moderating as it flows to the south and east, will bring a hard freeze to the Gulf Coast and northern Florida over the next few days.

Since the cold, dense air behind these Arctic fronts is usually rather shallow, the higher terrain of the High Plains and Front Range often escapes the most severe air, which drains southward through the Missouri and Mississippi Valleys. Today, Denver, Colorado, will be in the 40s(F) while here in Columbia, Missouri, we'll top out in the mid teens (after an overnight low of zero).

Blue Moon

The new year arrived with a blue moon shining in the clear, cold winter sky. Of course, the moon was not actually blue in color but it was the second full moon to occur in December, 2009. Over the years, there have been a number of definitions for a blue moon, including the second full moon in a calendar month and one of four full moons (usually the third) to occur within a season. Due to its variable definition, some kind of blue moon will occur in about three of four years.

Such designations, infused with mythology, imply that the moon's orbit is somehow disrupted, perhaps by supernatural powers, to produce the "extra" event. This, of course, is an illusion; the lunar cycle is not changing, although our lone, natural satellite is gradually moving further away from the Earth. Rather, the occurrence of blue moons reflects the inexact nature of the human calendar.

Once again, man has a tendency to view nature from his own, self-important perspective. When events occur that don't fit our expectations (based on our brief life experience and limited understanding) we infuse them with mystical significance. For many, "unnatural" events are reassuring, providing evidence that there is a spiritual world beyond our physical Universe.

The Earth Year

On this last day of 2009, it is important to realize that, beyond our home planet, a year, the cherished span by which we measure our history and our lives, is merely a segment of time. And while the duration of a year correlates with the period of Earth's orbit around the sun, the specific timing of man's calendar year is not tied to any natural cycle; rather, it is a product of human culture, influenced by politics and religion.

It might be argued that our year should begin at the winter solstice (the beginning of the solar cycle as perceived from Earth) but that would produce a 6 month variance of the calendar between the Northern and Southern Hemispheres. Of course, were it not for the tilt of our planet's axis, the seasons would not exist and we would not have solstices. If that were the case, the period of sunlight (for any given location) would not vary through the year and humans would likely be fixated on the moon, measuring our lives and our history in lunar cycles.

Beyond Earth, a year has no more significance than, say, 23 seconds, 51 hours or 813 days; it is just our measure of time based on our planet's orbit and on our experience of seasonal change. If we lived on Mercury, our year would be 88 Earth-days long while, on Neptune, an Earth-year would take us only 1/165 of the way around the sun. When viewed from the perspective of our galaxy, a year becomes even less significant as a period of time; it takes somewhere in the neighborhood of 230-250 million years for our solar system to orbit the center of the Milky Way. As in all aspects of natural science, it is important to acknowledge that our perspective, as observers from planet Earth, can temper our understanding of the Universe. Happy New Year!

The Threat of Argument

Argument, the unruly and emotionally-charged cousin of discussion, is often triggered by disrespect, intolerance and selfishness. While arguments are common in human relationships, they seem to be an increasingly common form of public interaction, threatening the welfare of society as a whole.

Recent town meetings to discuss health care policy descended into shouting matches, a Congressman became a folk hero by interrupting a Presidential speech to call him a liar and Capitol Hill has broken into polarized camps. All of this is fueled by an increasing assortment of talk media where bombastic moderators (from the left and right) invite guests from the political fringe and encourage heated argument, all the while interrupting with their own self-righteous remarks. In like manner, "reality shows" of courtroom antics and dysfunctional families entertain us with open combat between attention-starved participants, seeking their brief but fleeting opportunity for fame.

While open debate, dissent and calm discussion are essential to the health of democracy, crass and manufactured arguments have no place in government, entertainment or education. Nothing is accomplished, a poor example is set for our children, disrespect and intolerance are encouraged and stress is induced in participants and viewers alike. Unfortunately, an increasingly large segment of society seems to be entertained by this behavior and by the media programming that supports it; for the rest of us, it is time to vote with our ballots and our remotes.

Formation of Waterfalls

Liquid water, acting under the force of gravity, has sculpted spectacular landscapes across our globe and waterfalls are among the most beautiful and inspiring. Most waterfalls develop where a stream passes a geologic boundary, crossing from a hard, resistant bedrock to a softer, less resistant one; this causes an abrupt drop in the level of the stream flow. The "fall line" of the southeastern U.S. offers an excellent example of this process; here, rivers flowing from the Southern Appalachians to the Atlantic all possess significant waterfalls at the boundary of the Piedmont (underlain with hard igneous and metamorphic rock) and the Coastal Plain (composed of soft sedimentary deposits).

Once waterfalls form at these geologic boundaries, they begin to erode upstream and, over thousands of years, produce rugged gorges through the hard bedrock; an excellent example is provided by the Niagara Gorge, which formed (and continues to develop) as the falls cut their way upstream through the Niagara Escarpment. In other areas, waterfalls form when the walls of river valleys are altered by glaciers or landslides; tributaries that once descended through side canyons now drop precipitously to the valley floor; Yosemite Falls is perhaps North America's most spectacular example.

Some waterfalls occur beneath the surface of our planet, developing at sinkholes where the roof of a cave has collapsed. In these karst landscapes, thick layers of soluble bedrock (limestone or dolomite) lie just beneath the surface, often covered by a relatively thin veneer of sandstone. Cracks in the overlying rock allow rainwater and snowmelt to percolate into the limestone, eventually opening vast, underground networks of streams and caves. Surface streams drain toward these sinkholes and, once the underlying cave is spacious enough, a waterfall forms.

Window on Winter

While I enjoy winter hikes, on days like today, with frigid air and wind-blown snow, a good novel often sounds more inviting. Fortunately, we have a feeder just outside our picture window and the harsh conditions bring a wide variety of birds to the edge of our family room.

Feeding groups of chickadees, titmice, white-breasted nuthatches and downy woodpeckers appear on a regular basis and northern cardinals, especially bright against the bleak, winter landscape, are more than welcome visitors. Now and then, an unruly mob of house sparrows and starlings invades the scene; though not overly fond of the sunflower seed, they are voracious scavengers and, while searching through the contents, scatter much of the seed for our ground feeders. The latter include juncos, white-throated sparrows, cardinals, mourning doves and an occasional fox sparrow. Among other visitors are red-bellied woodpeckers, house finches, purple finches, Carolina wrens, hairy woodpeckers and those erratic red-breasted nuthatches. Of course, gray and fox squirrels grab what they can and, toward dusk, an opossum may wander in to scour the site for fallen seed.

Amateur naturalists and beginning bird watchers are often surprised to discover the variety of birds that inhabit our residential areas. All it takes is a well-placed feeder and cold, snowy weather to provide an entertaining window on nature's diversity.

Christmas Pinwheel

Yesterday's winter storm is centered over Iowa this morning and its counterclockwise winds are producing dramatic and ironic variations in the holiday weather. Strong southerly winds ahead of the storm are pushing relatively warm, moist air far to the north while cold, northerly winds to its west are bringing frigid air to the deep south. At this hour, the temperature in Dallas sits at 31 degrees F while it is five degrees warmer in northern Wisconsin; Chicago enjoys a balmy 42 degrees though, half a State to the southwest, Des Moines shivers at 19.

Northwest of the central low, the warm, humid air is being pushed over the dense, Arctic air, producing heavy snow which, combined with strong north winds behind the cold front, has created blizzard conditions across western Minnesota, the eastern Dakotas and down the Nebraska-Iowa border. Here in Missouri, wrap-around flurries, caught in a gusty, west wind, have arrived just in time for Christmas; the temperature is 17 F and is forecast to remain near 20 degrees throughout the day.

Powerful, slow moving storms often produce a marked contrast in weather over short distances and, as is evident today, one's latitude neither rules out nor guarantees a snowy Christmas. Like giant pinwheels, these massive systems can mix north with south in a sudden and dramatic fashion.

From April to December

Last evening, as a massive winter storm swirled over the Central Plains, thunderstorms rolled across Missouri, swept northward in advance of the cold front. Dropping torrential rain, the storms were accompanied by balmy, spring-like air and, by dawn, the thermometer sat at 50 degrees F.

Though such balmy interludes are common here during the winter months, the potency of the thunderstorms was a bit unusual, confirming the tremendous amount of energy in this latest storm system; to our southwest, the trailing cold front ignited tornadic supercells in east Texas while, north of the storm, blizzards raged across Minnesota and the Dakotas.

Contrary to the original forecast, the Midwest low has apparently weakened while a secondary low, which developed over Oklahoma, has strengthened, bringing heavy snow to central Oklahoma, northern Texas and southeastern Kansas. As this low tracks northeastward, we will remain in the warm (rainy) sector today but, as its front sweeps in from the west, our temperature will plummet; in concert, snow will develop, northwest winds will strafe the Heartland and December will reclaim Missouri.

The Evolution of Thought

Nervous systems first appeared in primitive marine life, billions of years ago. These earliest systems were reflexive in nature; stimuli (light, touch, pressure waves, etc.) would trigger a response (movement toward or away from the stimulus). Such mechanisms were essential to survival, playing an important role in feeding, defense and reproductive behavior.

As evolution produced more complex life forms, the neurological system developed in concert. Special sensory organs permitted more sophisticated forms of sight, hearing, smell and coordination; we can easily identify this progression in the modern representatives of animal families, from mollusks to mammals. Up through birds and most mammals, the neurologic system is primarily limited to peripheral nerves, spinal cord, brain stem and cerebellum; the brain stem controls basic functioning (such as respiration) while the cerebellum is critical to balance and coordination. The cerebral cortex, with its highly complex network of neurons, is the latest product of neurologic evolution, adding the capacity to think, reason, interpret, remember, learn, create and communicate in sophisticated ways.

While a primitive cerebral cortex is found in all birds and mammals, it has reached its highest form of development in primates; of course, humans are the most advanced primates and our cerebrum is, by far, the most complex. Indeed, our brain power has developed to the point where many humans conclude that we are divine creatures, superior to and separated from all lower forms of animal life. Yet, anatomic evidence demonstrates a clear evolutionary progression of the nervous system and medical science has shown a convincing correlation between specific brain injuries (via trauma, stroke, tumor, congenital deformity) and the loss of specific neurologic capabilities. Though difficult for many to accept, our thoughts, memories and emotions are the products of neuronal pathways and brain chemistry.

Creeping toward Spring

Now that we have crossed the winter solstice, the Northern Hemisphere begins its long, steady march toward spring. Too slow for many humans, the sun's angle will inch higher in the southern sky and, as a consequence, its rays will more directly impact the lands north of the equator. By the summer solstice, on or about June 21, it will reach its zenith (as our Hemisphere is at its maximum tilt toward the sun) and we will enjoy the longest day of the year.

Though our days will lengthen incrementally, we will not appreciate significant warming for another couple of months; in fact, at central latitudes of North America, the coldest days of the year (by average highs and lows) occur during the third week in January. While the sun angle will be too low to provide significant warming until mid February, we still enjoy balmy interludes as weather systems pump mild air up from the south.

Over time, the frozen ground will thaw, plants will germinate, birds will sing and our faith will be restored. Until then, we can enjoy the snowscapes, star gaze on clear winter nights, listen for the hoot of owls and dream of spring.