Insects play an important role in the natural world throughout the year. During winter, when most species are in suspended animation as eggs or pupae, these primary consumers provide important nourishment for birds and small mammals. Come spring, as the soil thaws, new vegetation appears and the ponds open, they begin to emerge; the tide of their recovery peaks by early summer and continues until the frosty nights of autumn.
Today's hot, humid weather has the annual cicadas buzzing for the first time this season. Down at the local wetland, hordes of dragonflies were hunting across the still waters, where whirligig beetles made frenzied patterns on the surface. Mosquitoes will rise from the marsh this evening and fireflies will flash from residential trees and shrubs, delighting adults and children alike. Then, of course, there are the numerous beetles, butterfies, moths, flies, crickets, grasshoppers and other insects that inhabit our woodlands and fields.
Checking the explosive population of these prolific creatures are the many secondary consumers: fish, frogs, lizards, snakes, turtles, birds and small mammals. Were in not for their hunting skills, we would soon be overrun by the bugs of summer!
Sunday, June 15, 2008
Saturday, June 14, 2008
Nighthawk at Noon
Common nighthawks are summer residents throughout most of North America and we tend to associate them with calm, summer evenings when they hawk for insects above our cities and towns. Easily identified by their halting flight, loud "peents" and prominent white wing patches, they are best observed at dusk; they are also common at sports stadiums where the bright lights concentrate their prey.
But, unlike other nightjars (such as whip-poor-wills and chuck-will's-widows), the common nighthawk is often active during the day, especially after heavy rains send clouds of insects into the air. And though they are generally associated with open woodlands and urban areas, they inhabit a wide variety of landscape. Today, travelling along I-70 in western Kansas, I watched a nighthawk hunt above a crop field and then veer across the highway; it was noon, the sky was clear and the temperature was 85 degrees F.
Common nighthawks roost on low branches, directly on the ground or on flat rooftops. Two eggs are laid on these level surfaces (with little, if any, nest material) and incubated by the female. I suspect today's high noon hunter had a pair of nestlings to feed.
But, unlike other nightjars (such as whip-poor-wills and chuck-will's-widows), the common nighthawk is often active during the day, especially after heavy rains send clouds of insects into the air. And though they are generally associated with open woodlands and urban areas, they inhabit a wide variety of landscape. Today, travelling along I-70 in western Kansas, I watched a nighthawk hunt above a crop field and then veer across the highway; it was noon, the sky was clear and the temperature was 85 degrees F.
Common nighthawks roost on low branches, directly on the ground or on flat rooftops. Two eggs are laid on these level surfaces (with little, if any, nest material) and incubated by the female. I suspect today's high noon hunter had a pair of nestlings to feed.
Friday, June 13, 2008
Castlewood Canyon
Rising on the Palmer Divide, Cherry Creek flows northward across the Colorado Piedmont and joins the South Platte River in downtown Denver. Along the way, the Creek has carved a scenic canyon through the mesa country of southern Douglas County. Now protected as a State Park, Castlewood Canyon is an excellent destination for hiking and nature study; the Visitor Center and primary entrance are on the west side of Colorado 83, several miles south of Franktown.
The Canyon, like mesas throughout the region, is capped by Castle Rock Conglomerate, deposited by the ancient South Platte River, which originally flowed eastward onto the High Plains just north of the Palmer Divide. An open forest of ponderosa pine cloaks the walls of the canyon, mixing with stands of juniper and scrub oak. Ten miles of hiking trails lead through the preserve, following the creek, snaking up the canyon slopes and meandering atop the rim; one loop crosses the old Castlewood Dam, constructed for irrigation purposes in 1890 and destroyed by a flood in 1936.
In addition to the scenic vistas, visitors will find an excellent variety of wildlife at Castlewood Canyon State Park. Turkey vultures are common, soaring above the canyon walls, and the raptor population includes golden eagles, red-tailed hawks, Swainson's hawks and prairie falcons; great horned owls also patrol the refuge, joined by northern saw-whet owls during the colder months. Magpies, scrub jays and canyon wrens inhabit the Park throughout the year; summer residents include Virginia's warblers, black-headed grosbeaks, green-tailed towhees, rock wrens, broad-tailed hummingbirds, Say's phoebes, lesser goldfinches and common poor-wills. American dippers and belted kingfishers may be found along the creek and, contrary to expectations, great blue herons nest within the Park. Resident mammals include mule and white-tailed deer, rock squirrels, Colorado chipmunks, muskrat, raccoons, beaver, red fox and coyotes; visitors are advised to watch for western rattlesnakes along the trails!
The Canyon, like mesas throughout the region, is capped by Castle Rock Conglomerate, deposited by the ancient South Platte River, which originally flowed eastward onto the High Plains just north of the Palmer Divide. An open forest of ponderosa pine cloaks the walls of the canyon, mixing with stands of juniper and scrub oak. Ten miles of hiking trails lead through the preserve, following the creek, snaking up the canyon slopes and meandering atop the rim; one loop crosses the old Castlewood Dam, constructed for irrigation purposes in 1890 and destroyed by a flood in 1936.
In addition to the scenic vistas, visitors will find an excellent variety of wildlife at Castlewood Canyon State Park. Turkey vultures are common, soaring above the canyon walls, and the raptor population includes golden eagles, red-tailed hawks, Swainson's hawks and prairie falcons; great horned owls also patrol the refuge, joined by northern saw-whet owls during the colder months. Magpies, scrub jays and canyon wrens inhabit the Park throughout the year; summer residents include Virginia's warblers, black-headed grosbeaks, green-tailed towhees, rock wrens, broad-tailed hummingbirds, Say's phoebes, lesser goldfinches and common poor-wills. American dippers and belted kingfishers may be found along the creek and, contrary to expectations, great blue herons nest within the Park. Resident mammals include mule and white-tailed deer, rock squirrels, Colorado chipmunks, muskrat, raccoons, beaver, red fox and coyotes; visitors are advised to watch for western rattlesnakes along the trails!
Thursday, June 12, 2008
Living in Wild Places
Not far from our farm, in Littleton, Colorado, is a new residential development called "Fox Haven." And it probably was before the houses were built, with their decks and privacy fences. Home builders know that many Americans like the feeling of living in the country and suburban developments are thus named accordingly. They also know that affluent Americans, while often very supportive of conservation organizations and recycling programs, don't want a recycled house; rather, they prefer the new models with all the latest features.
As a result, suburban sprawl continues, inner cities decay, long, congested commutes are the rule and wildlife habitat is destroyed. Of course, all towns, cities and farms were once wild areas and humans have some impact on natural ecosystems no matter where they live. Population control, development restrictions, open space protection and improved mass transit must all be part of the solution.
Long a poster child for suburban sprawl, Metro Denver has taken some important steps to reverse that image. Downtown residential development, a new light rail system and an excellent network of greenbelts, open spaces and parks have made the region more eco-friendly. Nevertheless, housing developments and their associated retail centers keep pushing onto the plains and into the foothills, natural habitat is lost and new home owners demand action when their cat or poodle is dinner for a coyote.
As a result, suburban sprawl continues, inner cities decay, long, congested commutes are the rule and wildlife habitat is destroyed. Of course, all towns, cities and farms were once wild areas and humans have some impact on natural ecosystems no matter where they live. Population control, development restrictions, open space protection and improved mass transit must all be part of the solution.
Long a poster child for suburban sprawl, Metro Denver has taken some important steps to reverse that image. Downtown residential development, a new light rail system and an excellent network of greenbelts, open spaces and parks have made the region more eco-friendly. Nevertheless, housing developments and their associated retail centers keep pushing onto the plains and into the foothills, natural habitat is lost and new home owners demand action when their cat or poodle is dinner for a coyote.
Wednesday, June 11, 2008
Night Winds
After reaching a high in the low 90s yesterday, we are sitting at 61 in Denver this afternoon. The change developed in the middle of the night as a period of strong north winds lashed the trees and rattled the window shades. That potent cold front encountered warm, dry air along the Front Range and no rain or snow developed. By early this morning, our temperature bottomed out at 44 degrees F.
Accompanied by the usual clear, sunny skies, the cool air was just right for yard work, certainly more comfortable than the heat of yesterday afternoon! As the front moved eastward, tied to a low in central Montana, we experienced a brief period of "upslope" late this morning; the northeast winds forced air to rise across the topography of eastern and central Colorado, producing clouds and a few showers along the Front Range and north slope of the Palmer Divide.
By early afternoon, the wind had shifted from the northwest, down-sloping east of the Continental Divide and clearing out the skies. The temperature will stay in the sixties with this northwest flow but, by tomorrow, on southwest winds, we'll bask in the seventies once again. Throw in a stray thunderstorm or two and that would complete a typical summer sequence along the Colorado Front Range.
Accompanied by the usual clear, sunny skies, the cool air was just right for yard work, certainly more comfortable than the heat of yesterday afternoon! As the front moved eastward, tied to a low in central Montana, we experienced a brief period of "upslope" late this morning; the northeast winds forced air to rise across the topography of eastern and central Colorado, producing clouds and a few showers along the Front Range and north slope of the Palmer Divide.
By early afternoon, the wind had shifted from the northwest, down-sloping east of the Continental Divide and clearing out the skies. The temperature will stay in the sixties with this northwest flow but, by tomorrow, on southwest winds, we'll bask in the seventies once again. Throw in a stray thunderstorm or two and that would complete a typical summer sequence along the Colorado Front Range.
Tuesday, June 10, 2008
The Chosen Species
Man is obviously not the largest or most powerful species on the planet. And, despite our slow maturation, a number of species have longer lives. Our sight is far inferior to that of raptors and the family dog has hearing and olfactory skills that are well beyond human capability. Many species outshine us when it comes to athletic talents (running, swimming, climbing, diving etc.) and almost all have survived the challenges of earth's ecosystems far longer than we have.
When humans first appeared, about 125,000 years ago, the Universe was almost 13.7 billion years old and the Earth was nearing 4.6 billion years of age. Though often ridiculed as a failed life form, the dinosaurs inhabited the planet for 160 million years and even some of Earth's current species (sharks and horseshoe crabs, for example) were present long before the first dinosaurs appeared. Next to humans, the youngest surviving mammal species is the Arctic fox, which has been around twice as long as humans.
But humans are, indeed, the most intelligent species in the history of our planet and this intelligence has given us the audacity to conclude that we are the culmination of evolutionary history. Furthermore, this intellectual capability has led us to imagine that all other species have been placed on this planet to serve our needs. We, by our own conclusion, are the chosen species, the pinnacle of "God's creation." Whether this assessment applies to intelligent life forms in other solar systems and across other galaxies is generally not addressed!
When humans first appeared, about 125,000 years ago, the Universe was almost 13.7 billion years old and the Earth was nearing 4.6 billion years of age. Though often ridiculed as a failed life form, the dinosaurs inhabited the planet for 160 million years and even some of Earth's current species (sharks and horseshoe crabs, for example) were present long before the first dinosaurs appeared. Next to humans, the youngest surviving mammal species is the Arctic fox, which has been around twice as long as humans.
But humans are, indeed, the most intelligent species in the history of our planet and this intelligence has given us the audacity to conclude that we are the culmination of evolutionary history. Furthermore, this intellectual capability has led us to imagine that all other species have been placed on this planet to serve our needs. We, by our own conclusion, are the chosen species, the pinnacle of "God's creation." Whether this assessment applies to intelligent life forms in other solar systems and across other galaxies is generally not addressed!
Monday, June 9, 2008
A Cool, Bright Morning
Despite the crystal-clear sky and brilliant sunshine, it was rather cool along the South Platte this morning, with a temperature near fifty. But, if anything, the coolness seemed to increase wildlife activity across the floodplain.
Red-winged blackbirds and killdeer provided a steady background chorus while great blue herons, black-crowned night herons and double-crested cormorants moved along the river. A mother wood duck ushered her brood across a marsh-lined pond and a lone beaver cruised one of the larger lakes. A flock of cedar waxwings moved through the riverside woods and mixed squadrons of tree and barn swallows swooped above the floodplain, feasting on clouds of insects. Though we didn't find snakes on this cool morning, six-lined racerunners were abundant, scurrying into the leaf litter as we approached. Other sightings included yellow warblers, American kestrels, red-tailed hawks and a lone white pelican.
The highlight of the morning was a mother common merganser with her six rambunctious youngsters. Following mom across a broad meander of the South Platte, they took turns hopping onto her back and bumping one another into the water. Sporting mom's reddish head feathers (the males will molt to their father's plumage by next spring) they huddled close to their protector when other birds flew by; at one point, a great blue heron landed too close for comfort and the mother charged, sending the intruder into squawking retreat.
Red-winged blackbirds and killdeer provided a steady background chorus while great blue herons, black-crowned night herons and double-crested cormorants moved along the river. A mother wood duck ushered her brood across a marsh-lined pond and a lone beaver cruised one of the larger lakes. A flock of cedar waxwings moved through the riverside woods and mixed squadrons of tree and barn swallows swooped above the floodplain, feasting on clouds of insects. Though we didn't find snakes on this cool morning, six-lined racerunners were abundant, scurrying into the leaf litter as we approached. Other sightings included yellow warblers, American kestrels, red-tailed hawks and a lone white pelican.
The highlight of the morning was a mother common merganser with her six rambunctious youngsters. Following mom across a broad meander of the South Platte, they took turns hopping onto her back and bumping one another into the water. Sporting mom's reddish head feathers (the males will molt to their father's plumage by next spring) they huddled close to their protector when other birds flew by; at one point, a great blue heron landed too close for comfort and the mother charged, sending the intruder into squawking retreat.
Sunday, June 8, 2008
Tale of Two Fronts
We left Columbia this morning in warm, humid air, the temperature already in the mid seventies. Heading west into Kansas, the south wind intensified and dark clouds loomed on the western horizon. While the larger, more powerful storms stayed to our north (closer to the center of low pressure) the trailing cold front was clearly marked by a line of dark clouds, stretching from the northeast to the southwest. We crossed the front beneath this swath (just east of Salina), enduring a brief period of rain.
West of the front, the air was noticeably cooler and drier. A mild northwest breeze replaced the southern gale and the sky was soon cloudless. Brilliant sunshine illuminated the fields of central and western Kansas before a second front approached from the northwest. Like a distant range of mountains, the clouds towered above the High Plains and, as we grew closer, their dark underbellies shrouded the sky. Heavy rains developed west of Flagler, Colorado, but, thankfully, there was not enough instability for high winds or hail to develop. North of Limon, beyond the Palmer Divide, the clouds dissipated and sunshine lit the high peaks of the Front Range.
As is typical with fast moving, western fronts, Denver received little precipitation. Pushing across the Rockies, these fronts create downsloping winds along the urban corridor, injecting warm, dry air into the area. This phenomenon keeps most of the rain out on the Eastern Plains, leaving only curtains of virga (precipitation that evaporates before hitting the ground) throughout the Front Range cities.
West of the front, the air was noticeably cooler and drier. A mild northwest breeze replaced the southern gale and the sky was soon cloudless. Brilliant sunshine illuminated the fields of central and western Kansas before a second front approached from the northwest. Like a distant range of mountains, the clouds towered above the High Plains and, as we grew closer, their dark underbellies shrouded the sky. Heavy rains developed west of Flagler, Colorado, but, thankfully, there was not enough instability for high winds or hail to develop. North of Limon, beyond the Palmer Divide, the clouds dissipated and sunshine lit the high peaks of the Front Range.
As is typical with fast moving, western fronts, Denver received little precipitation. Pushing across the Rockies, these fronts create downsloping winds along the urban corridor, injecting warm, dry air into the area. This phenomenon keeps most of the rain out on the Eastern Plains, leaving only curtains of virga (precipitation that evaporates before hitting the ground) throughout the Front Range cities.
Saturday, June 7, 2008
Fathers and Hope
Having evolved as hunters and protectors, human males are predisposed to violent behavior. Fortunately, the development of human culture has served to reign in this tendency but, as we all know, wars and violent crimes persist, almost always at the hands of men.
With Father's Day on the horizon, let's recognize that our best hope for ending this recurring cycle of violence lies with fathers themselves. Through their example, advice and influence, they have the best opportunity to direct their sons away from this innate behavior. On the other hand, their absence, emotionally and/or physically, significantly increases the risk of violent crime in these young men.
Life involves a series of choices and, without guidance, humans tend to follow their basal instincts. Fathers have both the duty and the opportunity to encourage their sons (and daughters) to make responsible decisions. They offer our best hope for a peaceful planet.
With Father's Day on the horizon, let's recognize that our best hope for ending this recurring cycle of violence lies with fathers themselves. Through their example, advice and influence, they have the best opportunity to direct their sons away from this innate behavior. On the other hand, their absence, emotionally and/or physically, significantly increases the risk of violent crime in these young men.
Life involves a series of choices and, without guidance, humans tend to follow their basal instincts. Fathers have both the duty and the opportunity to encourage their sons (and daughters) to make responsible decisions. They offer our best hope for a peaceful planet.
Man and Heat
As the season's first major heat wave envelops the eastern U.S., there will be many cases of heat exhaustion or heat stroke and, unfortunately, some heat-related deaths. Humans are more prone to heat-related illness than other animals for two reasons: we are intelligent and impatient.
Other animals are guided primarily by instinct. When excessive heat develops, they limit their activities, retreat to a cool den and wait for conditions to improve. Humans, on the other hand, are focused on time and take pride in a tough-minded approach to adversity. Unwilling to put off chores, reschedule events or demonstrate "weakness," they often remain active through the heat of the day, sometimes challenging nature by exercising in the face of extreme heat and humidity. "Just do it now" is their motto.
Of course, many heat-related deaths occur in individuals who are too frail or too young to care for themselves and, in those cases, other humans must accept responsibility. For the rest of us, common sense should be enough to keep us out of trouble. Unfortunately, pride and impatience often get in the way.
Other animals are guided primarily by instinct. When excessive heat develops, they limit their activities, retreat to a cool den and wait for conditions to improve. Humans, on the other hand, are focused on time and take pride in a tough-minded approach to adversity. Unwilling to put off chores, reschedule events or demonstrate "weakness," they often remain active through the heat of the day, sometimes challenging nature by exercising in the face of extreme heat and humidity. "Just do it now" is their motto.
Of course, many heat-related deaths occur in individuals who are too frail or too young to care for themselves and, in those cases, other humans must accept responsibility. For the rest of us, common sense should be enough to keep us out of trouble. Unfortunately, pride and impatience often get in the way.
Friday, June 6, 2008
Mountain Weather
This summer, many hikers and campers will head to the mountains, hoping to recharge their souls and to escape the heat of the lowlands. For their own health and safety, it is important that they are familiar with the challenges and fickle nature of mountain weather.
All other factors remaining equal, the temperature will fall 3.5 degrees F for every 1000 feet of elevation gain. In addition, high winds are common along mountain slopes, adding to the chilling effect of the altitude. On the other hand, the thin atmosphere increases direct warming from the sun and reduces protection from UV radiation. For all of these reasons, it is best to wear layers of clothing (including a waterproof parka) that can be adjusted through the course of the day; while staying warm is important, sweating will actually increase your risk of hypothermia should clouds or storms roll in. Obviously, sun screen and UV-protective sun glasses are also important equipment for any mountain excursion.
During the night, cold air sinks into the mountain valleys and onto the adjacent plains; come morning, the flow reverses as the lowlands begin to warm up. This rising air, which cools and saturates as it moves up the slope, sets the stage for thunderstorm development above the mountain ridges. These storms usually form by early afternoon and those who plan to hike above timberline should retreat from the open tundra by noon; lightening is a significant threat to those who enter the alpine landscape. Finally, the thin air and high altitude augment radiation of heat, producing a dramatic fall in temperature after sunset; a tent, a quality sleeping bag, warm, layered clothing (including a sock hat) and high-energy food are essential to prevent hypothermia.
All other factors remaining equal, the temperature will fall 3.5 degrees F for every 1000 feet of elevation gain. In addition, high winds are common along mountain slopes, adding to the chilling effect of the altitude. On the other hand, the thin atmosphere increases direct warming from the sun and reduces protection from UV radiation. For all of these reasons, it is best to wear layers of clothing (including a waterproof parka) that can be adjusted through the course of the day; while staying warm is important, sweating will actually increase your risk of hypothermia should clouds or storms roll in. Obviously, sun screen and UV-protective sun glasses are also important equipment for any mountain excursion.
During the night, cold air sinks into the mountain valleys and onto the adjacent plains; come morning, the flow reverses as the lowlands begin to warm up. This rising air, which cools and saturates as it moves up the slope, sets the stage for thunderstorm development above the mountain ridges. These storms usually form by early afternoon and those who plan to hike above timberline should retreat from the open tundra by noon; lightening is a significant threat to those who enter the alpine landscape. Finally, the thin air and high altitude augment radiation of heat, producing a dramatic fall in temperature after sunset; a tent, a quality sleeping bag, warm, layered clothing (including a sock hat) and high-energy food are essential to prevent hypothermia.
Thursday, June 5, 2008
Catalpas
The northern catalpas are blooming in Columbia this week. Natives of the mid Mississippi Valley, these trees are planted widely as ornamentals, primarily due to their showy, white flower clusters that appear in late spring. Rapid growers, northern catalpas may reach 100 feet or more and are easily recognized by their large, heart-shaped leaves. While they favor moist, well drained soil, they adapt to a wide range of soil conditions; in fact, we have a large catalpa on our farm in Colorado.
Southern catalpas, native to the Gulf Coast region, are smaller, topping out at 50 feet or so. Both species, though not in the legume family, produce long, narrow seed pods (up to 20 inches long) and have been known as Indian bean trees. Their wood, soft and brittle, is tolerant of moisture and has long been used for fencing and railroad ties; other uses include the manufacture of frames, furniture and bowls.
Catalpa worms, larvae of the catalpa sphinx moth, are the primary natural enemies of these trees. After overwintering in the soil as pupae, the moth emerges in spring and females deposit their eggs on the new vegetation. Caterpillars hatch by mid May and begin devouring the large leaves of the catalpa. Fortunately, for the trees, birds (such as cuckoos) are around to feast on the larvae and humans have discovered that catalpa worms are prime fish bait.
Southern catalpas, native to the Gulf Coast region, are smaller, topping out at 50 feet or so. Both species, though not in the legume family, produce long, narrow seed pods (up to 20 inches long) and have been known as Indian bean trees. Their wood, soft and brittle, is tolerant of moisture and has long been used for fencing and railroad ties; other uses include the manufacture of frames, furniture and bowls.
Catalpa worms, larvae of the catalpa sphinx moth, are the primary natural enemies of these trees. After overwintering in the soil as pupae, the moth emerges in spring and females deposit their eggs on the new vegetation. Caterpillars hatch by mid May and begin devouring the large leaves of the catalpa. Fortunately, for the trees, birds (such as cuckoos) are around to feast on the larvae and humans have discovered that catalpa worms are prime fish bait.
Wednesday, June 4, 2008
Genes, Experience and Luck
We are a product of three factors: genetics, experience and happen-stance; some might also include spirituality but I am inclined to lump that with experience.
Our genes determine our physical traits, our intellect and our talents; they also play a role in the development of our personality. In addition, genes confer a relative predisposition or immunity to various forms of disease, including pathophysiologic mechanisms related to the aging process.
Experience begins in utero and continues until the end of our life. It encompasses all of the influence that we receive from our parents, our family, our friends and everyone and everything that we encounter in our lives. Modified by our genetic makeup, this experience formulates our personality, our beliefs, our convictions, our interests and our lifestyle. These, in turn, affect our physical and mental health, our personal achievements and how we interact with the world around us.
Finally, happenstance can play a significant role in our life. Being at the right place at the right time or at the wrong place at the wrong time can, respectively, expand our horizons or shorten our life; casual meetings, accidental death, random murder and fatal infections are examples of such unforeseen and, in many cases, unpreventable events. However unsettling it may be, luck, good and bad, is part of life; some might call this the hand of God but I'll stick with happenstance.
Our genes determine our physical traits, our intellect and our talents; they also play a role in the development of our personality. In addition, genes confer a relative predisposition or immunity to various forms of disease, including pathophysiologic mechanisms related to the aging process.
Experience begins in utero and continues until the end of our life. It encompasses all of the influence that we receive from our parents, our family, our friends and everyone and everything that we encounter in our lives. Modified by our genetic makeup, this experience formulates our personality, our beliefs, our convictions, our interests and our lifestyle. These, in turn, affect our physical and mental health, our personal achievements and how we interact with the world around us.
Finally, happenstance can play a significant role in our life. Being at the right place at the right time or at the wrong place at the wrong time can, respectively, expand our horizons or shorten our life; casual meetings, accidental death, random murder and fatal infections are examples of such unforeseen and, in many cases, unpreventable events. However unsettling it may be, luck, good and bad, is part of life; some might call this the hand of God but I'll stick with happenstance.
Tuesday, June 3, 2008
Bully Birds
It was a calm, warm evening when I went out back to resume my novel. A Carolina wren sang from the far corner of the yard, a pair of chickadees moved through the redbud tree and a family of mourning doves huddled on a maple limb. Then, by page two, the starlings arrived!
Several pair of these despised immigrants flew into the yard, followed by their noisy, demanding youngsters. As the frenzied parents searched the shrubs and lawn for insects, their ravenous offspring watched from nearby trees, squawking incessantly. Though obnoxious by our standards, this aggressive behavior is inherent in their species and explains why starlings, introduced to North America in 1890, have now colonized most of the Continent.
Favoring cities, towns and farms, starlings nest in cavities, either in trees or in the sides of buildings. Often raising three broods in the course of a summer, they begin nesting earlier than many birds, occupying cavities that might otherwise be used by native species (such as bluebirds, great crested flycatchers, wrens and prothonotary warblers). Worse yet, they also evict competitors from these nesting sites, consuming their eggs in the process. Producing four to six offspring with each brood, it is no wonder that these aggressive and prolific birds have been able to spread so quickly.
During the cooler months, starlings gather in huge flocks. While their aerial ballets can be spectacular in open country, their urban congregations produce sanitation nightmares. On the positive side, these "ugly, obnoxious aliens" consume a prodigious number of harmful insects and, we must admit, they are one of nature's success stories.
Several pair of these despised immigrants flew into the yard, followed by their noisy, demanding youngsters. As the frenzied parents searched the shrubs and lawn for insects, their ravenous offspring watched from nearby trees, squawking incessantly. Though obnoxious by our standards, this aggressive behavior is inherent in their species and explains why starlings, introduced to North America in 1890, have now colonized most of the Continent.
Favoring cities, towns and farms, starlings nest in cavities, either in trees or in the sides of buildings. Often raising three broods in the course of a summer, they begin nesting earlier than many birds, occupying cavities that might otherwise be used by native species (such as bluebirds, great crested flycatchers, wrens and prothonotary warblers). Worse yet, they also evict competitors from these nesting sites, consuming their eggs in the process. Producing four to six offspring with each brood, it is no wonder that these aggressive and prolific birds have been able to spread so quickly.
During the cooler months, starlings gather in huge flocks. While their aerial ballets can be spectacular in open country, their urban congregations produce sanitation nightmares. On the positive side, these "ugly, obnoxious aliens" consume a prodigious number of harmful insects and, we must admit, they are one of nature's success stories.
Monday, June 2, 2008
Kentucky's Knob Belt
Most of eastern Kentucky is covered by the Appalachian Plateau, its western edge angling from the northeast to the southwest and running just east of Maysville, Berea and Somerset. Capped by the Pottsville Escarpment of Pennsylvanian sandstone, this edge rises up to 500 feet above the Lexington Peneplain (the Bluegrass Region), which covers the north-central part of the State.
The boundary of the Peneplain and the Plateau is characterized by a chain of "knobs," dissected from the Plateau by stream erosion; these topographic remnants, which comprise the Knob Belt, parallel the margin of the Appalachian Plateau from Maysville to Berea, producing scenic vistas for the traveller and regional diversity for the naturalist.
Perhaps the best place to explore this Edge of Appalachia is at the Berea College Forest, off Kentucky Route 21, 3 miles east of Berea. Over 19 miles of hiking trails lead up and along the narrow ridgetops of the preserve, offering spectacular views into the adjacent valleys and out across the Lexington Peneplain. One interesting feature is the Devil's Kitchen, a large recessed cave on the eastern edge of Indian Fort Mountain.
The boundary of the Peneplain and the Plateau is characterized by a chain of "knobs," dissected from the Plateau by stream erosion; these topographic remnants, which comprise the Knob Belt, parallel the margin of the Appalachian Plateau from Maysville to Berea, producing scenic vistas for the traveller and regional diversity for the naturalist.
Perhaps the best place to explore this Edge of Appalachia is at the Berea College Forest, off Kentucky Route 21, 3 miles east of Berea. Over 19 miles of hiking trails lead up and along the narrow ridgetops of the preserve, offering spectacular views into the adjacent valleys and out across the Lexington Peneplain. One interesting feature is the Devil's Kitchen, a large recessed cave on the eastern edge of Indian Fort Mountain.
Sunday, June 1, 2008
Science and Entertainment
Like many people, I am fascinated by the weather and have been a regular patron of the Weather Channel for many years. Unfortunately, in recent years, the program seems to be more focused on entertainment than on the science of meteorology. And while they have certainly played an important role in keeping the public informed regarding dangerous weather conditions, they have, in my opinion, begun to devote too much time to documentaries and travelogues.
This week, with the onset of Hurricane Season, the Weather Channel has plenty of fodder for entertainment. Their field celebrities are no doubt packed and ready to be dispatched to threatened sites and, though I'm sure that none of them want any death or destruction to result from the storms, I'm also sure they're hoping for more excitement than the last two seasons provided. But, considering the station's focus on hurricane preparation and evacuation, it seems counterproductive and downright silly that they feel the need to report from the heart of the action, standing in the wind and rain like defiant teenagers.
Anyone who pays close attention to weather forecasting knows that it is an interesting yet inexact science, with accuracy limited to 12 hours or so (often much less when it comes to storms). But, in the interest of entertainment, we are provided with seven-day forecasts and bizarre predictions of the number and severity of hurricanes to expect this season. When science is diluted by conjecture, credibility is lost and the important role that meteorologists play in public safety is compromised.
This week, with the onset of Hurricane Season, the Weather Channel has plenty of fodder for entertainment. Their field celebrities are no doubt packed and ready to be dispatched to threatened sites and, though I'm sure that none of them want any death or destruction to result from the storms, I'm also sure they're hoping for more excitement than the last two seasons provided. But, considering the station's focus on hurricane preparation and evacuation, it seems counterproductive and downright silly that they feel the need to report from the heart of the action, standing in the wind and rain like defiant teenagers.
Anyone who pays close attention to weather forecasting knows that it is an interesting yet inexact science, with accuracy limited to 12 hours or so (often much less when it comes to storms). But, in the interest of entertainment, we are provided with seven-day forecasts and bizarre predictions of the number and severity of hurricanes to expect this season. When science is diluted by conjecture, credibility is lost and the important role that meteorologists play in public safety is compromised.
Saturday, May 31, 2008
Prairie Crayfish
Most of us associate crayfish with southern bayous, shallow rivers and rocky creeks; some of us also recall the blind, albino crayfish that inhabit the streams and pools of caves. But there are also a large number of terrestrial species, of which the prairie crayfish is one of the more common.
Favoring wet meadows and floodplain grasslands, prairie crayfish dig burrows to access their cool, moist habitat, often leaving chimneys of mud around the entrance. Deep enough to reach the water table, these burrows may be far from surface water and often extend to depths of six feet. The crayfish emerge from the burrows at night (or during periods of cloudy, humid weather), wandering the grassland to find mates or food. In spring and fall, large numbers may be encountered on rainy mornings as they cross trails or country roads.
Terrestrial crayfish can be a nuisance in some crop or tree farm regions but otherwise play an important role in the wetland-prairie ecosystem. Their digging aerates and mixes the soil and their burrows provide wintering sites for amphibians, lizards and snakes. Showing little appreciation, these same creatures feed on the crayfish, as do herons, raccoons, otters, mink, fox and humans. Those that survive predation mate in March and the female crayfish carries fertilized eggs on her abdomen for two months; once hatched, the tiny youngsters remain attached to dear old mom through their first two molts before dropping off to fend for themselves.
Favoring wet meadows and floodplain grasslands, prairie crayfish dig burrows to access their cool, moist habitat, often leaving chimneys of mud around the entrance. Deep enough to reach the water table, these burrows may be far from surface water and often extend to depths of six feet. The crayfish emerge from the burrows at night (or during periods of cloudy, humid weather), wandering the grassland to find mates or food. In spring and fall, large numbers may be encountered on rainy mornings as they cross trails or country roads.
Terrestrial crayfish can be a nuisance in some crop or tree farm regions but otherwise play an important role in the wetland-prairie ecosystem. Their digging aerates and mixes the soil and their burrows provide wintering sites for amphibians, lizards and snakes. Showing little appreciation, these same creatures feed on the crayfish, as do herons, raccoons, otters, mink, fox and humans. Those that survive predation mate in March and the female crayfish carries fertilized eggs on her abdomen for two months; once hatched, the tiny youngsters remain attached to dear old mom through their first two molts before dropping off to fend for themselves.
Friday, May 30, 2008
Signs of Summer
After a long, cool spring, summer has taken control in mid Missouri. The canopy has closed in, the tulip trees (yellow poplars) are in bloom and the mimosas are leafing out, among the last trees to do so. Flower clusters are forming on the elderberry shrubs, roses adorn the fence lines and tiny walnuts are developing in the new growth of their parent trees.
All of the summer birds have returned, including a pair of great crested flycatchers that have been moving among our shade trees this week. A morning dove is incubating her second brood of the year, the third litter of cottontails are roaming the lawns and the "peents" of common nighthawks echo across the evening sky. And, finally, the toads are trilling from their nocturnal rendezvous sites.
A south wind has carried warm, moist air up from the Gulf of Mexico, providing fuel for thunderstorms later in the day. This mild flow is forecast to continue through the week as summer solidifies its hold on the lower Midwest. Indeed, as evidenced by the movement of severe weather from the southern to the northern Plains, the jet stream is retreating toward its more northern, summer pattern. Our attention will soon shift from tornadoes to hurricanes!
All of the summer birds have returned, including a pair of great crested flycatchers that have been moving among our shade trees this week. A morning dove is incubating her second brood of the year, the third litter of cottontails are roaming the lawns and the "peents" of common nighthawks echo across the evening sky. And, finally, the toads are trilling from their nocturnal rendezvous sites.
A south wind has carried warm, moist air up from the Gulf of Mexico, providing fuel for thunderstorms later in the day. This mild flow is forecast to continue through the week as summer solidifies its hold on the lower Midwest. Indeed, as evidenced by the movement of severe weather from the southern to the northern Plains, the jet stream is retreating toward its more northern, summer pattern. Our attention will soon shift from tornadoes to hurricanes!
Thursday, May 29, 2008
The Piedmont Puzzle
The Southeast Piedmont is a geophysical province that stretches from the Mid-Atlantic region to central Alabama. This broad swath of rolling terrain separates the Appalachian Mountains, to the west, from the Coastal Plain, to the south and east. For geologists, the formation of the Piedmont has long been a puzzle.
The Piedmont's bedrock is a mosaic of Precambrian and early Paleozoic rocks (1.2 billion to 500 million years old), represented by igneous and metamorphic components. Some of these formations contain rock that is not otherwise found within the North American craton, suggesting that they arrived as exotic terrains; volcanic components, on the other hand, indicate that they likely formed as offshore, island arcs before merging with the edge of the continent. Finally, areas of volcanic Triassic rock, found near the eastern edge of the Piedmont, are remnants of rifting between Africa and North America as Pangea split apart and the Atlantic began to open (almost 200 million years ago).
The many suture lines between the puzzle pieces of the Piedmont underwent some disruption during the rise of the Appalachians (250-300 million years ago), allowing plutons of magma to form within some of the rock layers. Eventually, as the encasing rock was worn away by erosion, these igneous monoliths were revealed; monadnocks, most common near the edge of the Appalachians, and Stone Mountain, near Atlanta, are excellent examples. Deep soil covers the bedrock in most areas of the Piedmont but, at the fall line (where this province abuts the Coastal Plain), the hard basement of the Piedmont is revealed by waterfalls.
The Piedmont's bedrock is a mosaic of Precambrian and early Paleozoic rocks (1.2 billion to 500 million years old), represented by igneous and metamorphic components. Some of these formations contain rock that is not otherwise found within the North American craton, suggesting that they arrived as exotic terrains; volcanic components, on the other hand, indicate that they likely formed as offshore, island arcs before merging with the edge of the continent. Finally, areas of volcanic Triassic rock, found near the eastern edge of the Piedmont, are remnants of rifting between Africa and North America as Pangea split apart and the Atlantic began to open (almost 200 million years ago).
The many suture lines between the puzzle pieces of the Piedmont underwent some disruption during the rise of the Appalachians (250-300 million years ago), allowing plutons of magma to form within some of the rock layers. Eventually, as the encasing rock was worn away by erosion, these igneous monoliths were revealed; monadnocks, most common near the edge of the Appalachians, and Stone Mountain, near Atlanta, are excellent examples. Deep soil covers the bedrock in most areas of the Piedmont but, at the fall line (where this province abuts the Coastal Plain), the hard basement of the Piedmont is revealed by waterfalls.
Wednesday, May 28, 2008
The Death of Orphans
Earlier this week, my wife and I saw three baby opossums in our yard. They were clearly younger and smaller than those I have seen clinging to the backs of their mothers in the past; newborn opossums generally nurse until they are two months of age and thereafter fend for themselves. Within two days of spotting the babies, I found all three is various stages of dismemberment, likely the victims of cats, owls or raccoons. It seems apparent that they were either abandoned by their mother or, more likely, that she herself was killed.
Premature death is, of course, common in the animal kingdom. Young birds and cottontails are often the victims of snakes, raptors and carnivorous mammals, including domestic cats. Indeed, the very young, the injured and the frail are the usual targets of natural predation, a process that keeps populations in check and maintains the overall health of the species and its ecosystem.
We prefer to focus on the beauty and serenity of nature but, to truly understand her cycles, we must acknowledge the roles that violence, death and decomposition play. Nature is neither fair nor sentimental.
Premature death is, of course, common in the animal kingdom. Young birds and cottontails are often the victims of snakes, raptors and carnivorous mammals, including domestic cats. Indeed, the very young, the injured and the frail are the usual targets of natural predation, a process that keeps populations in check and maintains the overall health of the species and its ecosystem.
We prefer to focus on the beauty and serenity of nature but, to truly understand her cycles, we must acknowledge the roles that violence, death and decomposition play. Nature is neither fair nor sentimental.
Tuesday, May 27, 2008
An Explosion of Life
After a few days of heavy rain and sultry weather, there has been an explosion of life at the Forum Nature Area, a local wetland-prairie preserve. The greenery is lush, the ponds and lakes are flooded and a variety of wildflowers color the landscape; the latter include yellow coreopsis, wild rose, buttercups and wild irises. The lead plants, typical shrubs of the mesic prairie, are also in bloom, their purple flower stalks attracting hordes of bees.
The bird population continues to grow, with yellow-billed cuckoos making an appearance this week. Other summer residents include green-backed herons, great blue herons, killdeer, spotted sandpipers, eastern kingbirds, gray catbirds, indigo buntings, eastern phoebes, common yellowthroats, eastern bluebirds and the ubiquitous red-winged blackbirds. Clouds of insects offer plentiful prey for tree swallows, barn swallows and chimney swifts while, along the shores, bullfrogs and green frogs have graced the scene, their distinctive calls rising from the wetland.
The highlight of yesterday's visit was a large congregation of northern water snakes, plying the shallows at the west end of the lake. Constantly on the move and showing no signs of stalking prey, they were likely males in search of a receptive female; this is their breeding season and, in fact, the source of their excitement was probably the large adult lounging in a nearby sapling (females are significantly larger than males). If impregnated, she will give birth to anywhere from 12 to 60 live young in late August.
The bird population continues to grow, with yellow-billed cuckoos making an appearance this week. Other summer residents include green-backed herons, great blue herons, killdeer, spotted sandpipers, eastern kingbirds, gray catbirds, indigo buntings, eastern phoebes, common yellowthroats, eastern bluebirds and the ubiquitous red-winged blackbirds. Clouds of insects offer plentiful prey for tree swallows, barn swallows and chimney swifts while, along the shores, bullfrogs and green frogs have graced the scene, their distinctive calls rising from the wetland.
The highlight of yesterday's visit was a large congregation of northern water snakes, plying the shallows at the west end of the lake. Constantly on the move and showing no signs of stalking prey, they were likely males in search of a receptive female; this is their breeding season and, in fact, the source of their excitement was probably the large adult lounging in a nearby sapling (females are significantly larger than males). If impregnated, she will give birth to anywhere from 12 to 60 live young in late August.
Monday, May 26, 2008
Rio Grande Rift
Ten million years ago, as the Miocene-Pliocene Uplift of the Intermountain West continued, fracture lines developed from southern Colorado to southern New Mexico and a long block of crust stopped rising with the surrounding terrain. Volcanism developed along some margins of the block and at other faults within the rift zone, creating lava flows, producing volcanic mountain ranges and showering the region with eruptive debris. In other areas, fault-block mountains formed, their steep walls facing the rift while their opposite slopes drop gently to the surrounding landscape. In concert with these events, erosion of the rising terrain along the margins of the block spread aprons of sand and gravel across the rift valley.
In southern Colorado, these events created the broad San Luis Valley, flanked by the San Juan and La Garita Mountains to the west and the high spine of the Sangre de Cristos to the east. Further south, the volcanic Jemez Mountains of northern New Mexico rise along the west edge of the rift while the fault-block Sandia and Manzano Ranges tower above its eastern edge, just east of Albuquerque. To the west of that city, a north-south line of volcanic peaks rise above a fault within the rift valley and, in southern New Mexico, volcanic and fault-block ranges mark the borders of the depression.
As noted above, thick layers of volcanic and erosional debris now fill the rift valley; 10,000 feet of this loosely compacted material has produced the flat landscape of the San Luis Valley and Albuquerque sits atop 5000 feet of sediment. The Rio Grande River, rising in the San Juans of southwestern Colorado, flows southward through the heart of the rift, slicing through the valley fill, including a thick lava bed west of Taos.
In southern Colorado, these events created the broad San Luis Valley, flanked by the San Juan and La Garita Mountains to the west and the high spine of the Sangre de Cristos to the east. Further south, the volcanic Jemez Mountains of northern New Mexico rise along the west edge of the rift while the fault-block Sandia and Manzano Ranges tower above its eastern edge, just east of Albuquerque. To the west of that city, a north-south line of volcanic peaks rise above a fault within the rift valley and, in southern New Mexico, volcanic and fault-block ranges mark the borders of the depression.
As noted above, thick layers of volcanic and erosional debris now fill the rift valley; 10,000 feet of this loosely compacted material has produced the flat landscape of the San Luis Valley and Albuquerque sits atop 5000 feet of sediment. The Rio Grande River, rising in the San Juans of southwestern Colorado, flows southward through the heart of the rift, slicing through the valley fill, including a thick lava bed west of Taos.
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