As the extreme heat expands eastward over the next few days, the subject of global warming will, not doubt, get plenty of air time. How soon we forget the chilly spring of 2008, which put Midwestern flora two weeks behind schedule!
While there is plenty of evidence that Earth's climate is gradually warming, regional heat waves have no relationship to that global phenomenon. Rather, like other local weather patterns (e.g. the excessive snow and rain in the Upper Midwest), they are a product of ocean currents and jet stream patterns. Indeed, one area of extreme weather often lies adjacent to an area that is experiencing the opposite conditions (e.g. the coexistence of Midwest flooding and the Southeastern drought); such opposite extremes are usually separated by a persistent frontal boundary that, itself, is governed by a stable jet stream.
Once again, our short life spans and inability to take the long view make us jump to the wrong conclusions. We focus on current weather records (and assume that they forecast a climate meltdown) while overlooking the fact that the previous record occurred a century ago! Despite this mid summer heat wave (not terribly unusual) we could easily face record cold next winter. By then, thoughts of global warning will be suppressed (if not welcomed).
Thursday, July 31, 2008
Wednesday, July 30, 2008
Big Oak Tree
Before the arrival of white settlers, a vast swamp forest covered most of the Mississippi floodplain. The fertile soil supported the growth of huge trees, dominated by water-loving species such as burr oak, sycamore, silver maple and bald cypress. By the 1930s, timber production and drainage for agriculture had destroyed most of this rich forest and only scattered remnants persist today. Big Oak Tree State Park, in southeast Missouri, protects one of these, a 1007 acre stand of virgin swamp forest; the park is west of Missouri Route 102, 11.3 miles south of East Prairie.
Accessed by a boardwalk trail, the woodland harbors twelve State Champion Trees, two of which are National Champions. Permanent avian residents include pileated and red-headed woodpeckers, hooded mergansers, barred owls and wild turkey; during the warmer months, they are joined by hooded and prothonotary warblers, Mississippi kites, common yellowthroats, fish crows and Louisiana waterthrushes. The Park is one of the best places in Missouri to find Swainson's warblers, which nest in stands of giant cane that dot the understory. Mink, raccoons, white-tailed deer and river otters are among the floodplain mammals.
The loss of swamp forest and marshlands along the Mississippi has reduced the ecological diversity of the floodplain, eliminated the natural filtering that wetlands provide and increased the risk of flooding in other low-lying areas. Furthermore, the agricultural lands and industrial ports that have replaced them are a steady source of pollutants that make their way into the River and, eventually, into the Gulf of Mexico. Naturalizing the floodplain, to the extent possible, is an essential step toward restoring this vital ecosystem.
Accessed by a boardwalk trail, the woodland harbors twelve State Champion Trees, two of which are National Champions. Permanent avian residents include pileated and red-headed woodpeckers, hooded mergansers, barred owls and wild turkey; during the warmer months, they are joined by hooded and prothonotary warblers, Mississippi kites, common yellowthroats, fish crows and Louisiana waterthrushes. The Park is one of the best places in Missouri to find Swainson's warblers, which nest in stands of giant cane that dot the understory. Mink, raccoons, white-tailed deer and river otters are among the floodplain mammals.
The loss of swamp forest and marshlands along the Mississippi has reduced the ecological diversity of the floodplain, eliminated the natural filtering that wetlands provide and increased the risk of flooding in other low-lying areas. Furthermore, the agricultural lands and industrial ports that have replaced them are a steady source of pollutants that make their way into the River and, eventually, into the Gulf of Mexico. Naturalizing the floodplain, to the extent possible, is an essential step toward restoring this vital ecosystem.
Monday, July 28, 2008
Dolly's U-Turn
As Hurricane Dolly made landfall in South Texas last week, a dome of high pressure was forming over the Southern Plains. Following the outer rim of that dome, Dolly moved westward into Mexico and then northwestward, stalling in southeast New Mexico and producing floods across that region. Over the past 24 hours, the storm remnants have drifted northward and the central low pressure now sits above the westernmost panhandle of Oklahoma, bringing upslope rains to the Colorado Front Range.
As Dolly continues to skirt the dome of high pressure, air within the dome is sinking, producing extreme heat across northern Texas, Oklahoma and Arkansas. By mid week, a Pacific cold front, moving down from the northwest, will sweep the remnant moisture of Dolly into the Heartland, producing storms across Kansas, Iowa and Missouri. Unfortunately, for residents of the Southern Plains, the high pressure dome will hold, the heat will persist and Dolly's final gasp will push off toward the Upper Midwest.
As Dolly continues to skirt the dome of high pressure, air within the dome is sinking, producing extreme heat across northern Texas, Oklahoma and Arkansas. By mid week, a Pacific cold front, moving down from the northwest, will sweep the remnant moisture of Dolly into the Heartland, producing storms across Kansas, Iowa and Missouri. Unfortunately, for residents of the Southern Plains, the high pressure dome will hold, the heat will persist and Dolly's final gasp will push off toward the Upper Midwest.
Sunday, July 27, 2008
Springville Marsh
At the end of the Pleistocene Ice Age, a vast wetland, known as the Big Spring Prairie, covered much of northwestern Ohio. Today, Springville Marsh, a State Nature Preserve, protects a 160 acre remnant of that ecosystem; characterized by flat terrain and abundant ground water, this relic has survived drainage, forest encroachment and the farmer's plow.
Accessed by a 1-mile trail, most of which crosses the marsh as an elevated boardwalk, this fascinating preserve is on Township Road 24 (west of U.S. 23), 4 miles north of Carey, Ohio. Visitors will find an extensive cat-tail marsh, with patches of twig rush, sedge and phragmites; islands of willow and shrubby dogwood dot the wetland, adding to the floral diversity. Rare species, such as Kalm's lobelia, bottle gentian, shrubby cinquefoil and fen orchids may be seen along the boardwalk.
Wetland residents include a variety of herons, egrets, soras, mink, long-tailed weasels, raccoons and red fox; spotted turtles, threatened in Ohio, may also be found. Open ponds, viewed from a duck blind or observation tower, attract a variety of waterfowl, especially during spring and fall migrations.
Accessed by a 1-mile trail, most of which crosses the marsh as an elevated boardwalk, this fascinating preserve is on Township Road 24 (west of U.S. 23), 4 miles north of Carey, Ohio. Visitors will find an extensive cat-tail marsh, with patches of twig rush, sedge and phragmites; islands of willow and shrubby dogwood dot the wetland, adding to the floral diversity. Rare species, such as Kalm's lobelia, bottle gentian, shrubby cinquefoil and fen orchids may be seen along the boardwalk.
Wetland residents include a variety of herons, egrets, soras, mink, long-tailed weasels, raccoons and red fox; spotted turtles, threatened in Ohio, may also be found. Open ponds, viewed from a duck blind or observation tower, attract a variety of waterfowl, especially during spring and fall migrations.
Saturday, July 26, 2008
The Pliocene
The Pliocene, the last epoch of the Tertiary Period, stretched from 10 to 2 million years ago. As it began, the Rio Grande Rift was forming in Colorado-New Mexico and the Tetons rose in Wyoming. Other geologic highlights of this Epoch included the formation of the Galapagos Islands (8 million years ago), the development of the San Francisco volcanic field of northern Arizona (6 MYA), the sculpting of the Grand Canyon (which continues today), the arrival of the Salinia Terrain (now Southern California), the formation of Kauai (5 MYA), the opening of the Gulf of California, the development of Oahu (4 MYA), the rise of the Sierra Batholith (which continues today), the arrival of Panama to connect North and South America, the formation of the Long Valley volcanic field in California, the appearance of Easter Island (3 MYA) and the opening of the Lake Baikal Rift (2.5 MYA).
New life forms of the Pliocene included sheep, goats, cattle, antelope and bison in Eurasia, mammoths in Africa and megatherium, a giant ground sloth, in South America; sea lions, seals, walruses and saber-toothed cats also appeared during this Epoch. Gorillas split from the human ancestral line 9 million years ago and chimpanzees followed two million years later.
Australopithecus, thought to represent the earliest hominid, appeared in the Rift Valley of Africa 4.5 MYA, followed by Homo habilis 2.5 MYA; the latter species had opposable thumbs and was the first hominid to use stone tools.
Toward the end of the Pliocene, Earth's climate was cooling. An ice cap had formed over the North Pole and glaciers appeared on Greenland. The stage was set for the Pleistocene Ice Age, which began about 2 million years ago; many climatologists believe that the Holocene, in which we live, is just a warm interglacial period of the Pleistocene and that another phase of glaciation will develop in 5-10 thousand years.
New life forms of the Pliocene included sheep, goats, cattle, antelope and bison in Eurasia, mammoths in Africa and megatherium, a giant ground sloth, in South America; sea lions, seals, walruses and saber-toothed cats also appeared during this Epoch. Gorillas split from the human ancestral line 9 million years ago and chimpanzees followed two million years later.
Australopithecus, thought to represent the earliest hominid, appeared in the Rift Valley of Africa 4.5 MYA, followed by Homo habilis 2.5 MYA; the latter species had opposable thumbs and was the first hominid to use stone tools.
Toward the end of the Pliocene, Earth's climate was cooling. An ice cap had formed over the North Pole and glaciers appeared on Greenland. The stage was set for the Pleistocene Ice Age, which began about 2 million years ago; many climatologists believe that the Holocene, in which we live, is just a warm interglacial period of the Pleistocene and that another phase of glaciation will develop in 5-10 thousand years.
Friday, July 25, 2008
Estivation
Estivation is essentially hibernation during periods of excessive heat or prolonged drought. An adaptation to environmental stress, this physiologic response is especially common in desert regions and in geographic areas that are characterized by dry seasons.
Land snails, terrestrial crustaceans and a wide variety of amphibians and reptiles are known to estivate. More than a retreat to cool or moist dens, this process involves a down-regulation of the animal's metabolism to preserve stored energy until environmental conditions improve. Many amphibians and invertebrates also secrete a membrane that protects them from dehydration through the estivation.
While many mammals den up during periods of excessive heat or drought, only a few species are known to estivate. Humans, of course, adapt to seasonal change with our various technologies but some of us (myself included), not being fans of hot weather, would love to estivate now and then.
Land snails, terrestrial crustaceans and a wide variety of amphibians and reptiles are known to estivate. More than a retreat to cool or moist dens, this process involves a down-regulation of the animal's metabolism to preserve stored energy until environmental conditions improve. Many amphibians and invertebrates also secrete a membrane that protects them from dehydration through the estivation.
While many mammals den up during periods of excessive heat or drought, only a few species are known to estivate. Humans, of course, adapt to seasonal change with our various technologies but some of us (myself included), not being fans of hot weather, would love to estivate now and then.
Thursday, July 24, 2008
Northeast Deluge
While the weather news was focused on Hurricane Dolly yesterday, a perfect rainmaker was developing across the Northeastern States. A cold front, stretching from the mid Atlantic region into New England, was attached to a potent but slow moving storm system, centered just north and east of the Great Lakes.
In concert, high pressure off the mid Atlantic coast was pushing in copious moisture from the ocean, including the tropical remnants of Cristobal. Encountering the cold front, this warm, saturated air was forced to rise, producing a chain of heavy thunderstorms along the front, which crept slowly to the east. Some storms dropped rain at rates of 3-4 inches per hour, triggering flash floods throughout the region.
This morning, the front was hugging the eastern shore, from Philadelphia to Boston, producing travel nightmares across the most populated swath of our country. Though Dolly is more powerful and destructive, the Northeast storm is likely to have a greater impact.
In concert, high pressure off the mid Atlantic coast was pushing in copious moisture from the ocean, including the tropical remnants of Cristobal. Encountering the cold front, this warm, saturated air was forced to rise, producing a chain of heavy thunderstorms along the front, which crept slowly to the east. Some storms dropped rain at rates of 3-4 inches per hour, triggering flash floods throughout the region.
This morning, the front was hugging the eastern shore, from Philadelphia to Boston, producing travel nightmares across the most populated swath of our country. Though Dolly is more powerful and destructive, the Northeast storm is likely to have a greater impact.
Tuesday, July 22, 2008
Dolly Watch
The Weather Channel, starved for tropical excitement over the past two years, is surely thrilled to have Tropical Storm Dolly spinning in the Gulf of Mexico. As one might expect, Jim Cantore, their superstar storm chaser, has been dispatched to Corpus Christi, Texas, to stand in the wind and rain as Dolly makes landfall. Unfortunately, as is often the case, the storm seems to be veering west of the forecast track and Jim may be heading for Brownsville to stay in the action.
Still expected to strengthen into a low level hurricane, Dolly will likely miss the oil and gas platforms of the northern Gulf but there is still hope that its remnants will bring drought relief to southern Texas. Should the storm move far enough to the north to threaten South Padre Island and Texas coastal cities, it will get front page billing in U.S. newspapers; should it stay south and wreak havoc on Mexican fishing villages, look for the story on page two or three.
Still expected to strengthen into a low level hurricane, Dolly will likely miss the oil and gas platforms of the northern Gulf but there is still hope that its remnants will bring drought relief to southern Texas. Should the storm move far enough to the north to threaten South Padre Island and Texas coastal cities, it will get front page billing in U.S. newspapers; should it stay south and wreak havoc on Mexican fishing villages, look for the story on page two or three.
Monday, July 21, 2008
Birding the Treetops
While it is relatively easy to observe birds that feed on the ground or in low shrubs, it can be a challenge to identify species that inhabit the forest canopy. Scarlet tanagers, wood pewees, red-eyed and yellow-throated vireos, olive-sided flycatchers, crossbills and many warblers are among the birds that tend to favor the treetops.
Novice birders are often frustrated by these species and even veteran bird watchers find it difficult to observe canopy birds without getting a serious case of neck strain. One of the better ways to solve this problem is to find a birding location that offers a view across (or even down to) the forest canopy. Rocky outcrops on the rim of a gorge or clearings on a wooded hillside are two examples. Such vantage points offer a comfortable and unobstructed view of the treetops and foster the patience that is often required to observe and identify these species. Of course, many parks and nature centers provide observation towers that serve the same purpose.
Novice birders are often frustrated by these species and even veteran bird watchers find it difficult to observe canopy birds without getting a serious case of neck strain. One of the better ways to solve this problem is to find a birding location that offers a view across (or even down to) the forest canopy. Rocky outcrops on the rim of a gorge or clearings on a wooded hillside are two examples. Such vantage points offer a comfortable and unobstructed view of the treetops and foster the patience that is often required to observe and identify these species. Of course, many parks and nature centers provide observation towers that serve the same purpose.
Saturday, July 19, 2008
July Soup
After five days in the thin, dry air of Colorado, I have returned to the hot, muggy summer of the American Midwest. Though the intense sunshine of the Front Range often produces afternoon highs in the 90s, the high elevation and thin atmosphere promote rapid cooling at night and early morning lows drop into the 50s. By contrast, the thick blanket of humid air in the Midwest serves to minimize the radiation of heat and we awaken to temperatures near 70.
By mid July, the jet stream has moved into Canada and high pressure builds across the Southern Plains. Pacific storms and their associated cold fronts are diverted across the northern tier of States and precipitation in most of the Central and Eastern U.S. is limited to scattered, pop-up thunderstorms and the occasional tropical system. At the same time, this high pressure over the plains is partly responsible for the seasonal monsoon of the Southwest, pulling Gulf moisture across Mexico and into the Four Corners region.
The sultry conditions will persist until the jet stream drifts southward, allowing pockets of cool, Canadian air to invade the Heartland. Though storms across the northern States may send weak cold fronts into the Midwest, significant, lasting relief must await a buckling of the jet stream itself. Don't count on that until mid September or so!
By mid July, the jet stream has moved into Canada and high pressure builds across the Southern Plains. Pacific storms and their associated cold fronts are diverted across the northern tier of States and precipitation in most of the Central and Eastern U.S. is limited to scattered, pop-up thunderstorms and the occasional tropical system. At the same time, this high pressure over the plains is partly responsible for the seasonal monsoon of the Southwest, pulling Gulf moisture across Mexico and into the Four Corners region.
The sultry conditions will persist until the jet stream drifts southward, allowing pockets of cool, Canadian air to invade the Heartland. Though storms across the northern States may send weak cold fronts into the Midwest, significant, lasting relief must await a buckling of the jet stream itself. Don't count on that until mid September or so!
Friday, July 18, 2008
The Pope and Global Warming
Pope Benedict, in Sydney, Australia, for a Catholic Convention, is receiving a great deal of attention for his concern about global warming. Exhorting his flock to combat the problem, he places emphasis on the conservation of natural resources and on efforts to reduce our production of greenhouse gases. But, in a rush to label him "the first Green Pope," reporters and admirers overlook the fact that his Church's stance on birth control is one of the key impediments to effectively dealing with this threat.
To the extent that humans are responsible for climate change, the unchecked growth of our population, especially in developing countries, is a primary factor. Technology and conservation measures will not be successful unless combined with efforts to reduce human population growth. If the Pope is truly alarmed by the prospects of climate-induced catastrophe, he would best serve our species and our planet by reversing the antiquated teachings of his Church.
To the extent that humans are responsible for climate change, the unchecked growth of our population, especially in developing countries, is a primary factor. Technology and conservation measures will not be successful unless combined with efforts to reduce human population growth. If the Pope is truly alarmed by the prospects of climate-induced catastrophe, he would best serve our species and our planet by reversing the antiquated teachings of his Church.
Thursday, July 17, 2008
Singing in the Heat
On hot, summer days, bird song is generally subdued. The high-pitched twitter of chimney swifts, brief tunes from the ever-cheerful chickadees and the buzzy chatter of house wrens are some of the few calls that pierce the oppressive heat. But, as is always the case in nature, there are exceptions.
This summer, a flock of lesser goldfinches has settled at our Littleton, Colorado, farm for the first time. Common across the foothill canyons and shrublands, they are much less common on the adjacent Piedmont and we are about five miles from the base of the mountains. For the past few days, the colorful males have been singing from dawn to dusk, indicating that their breeding season is underway. Like their cousin, the American goldfinch, this western species nests in the summer, timing the process with the peak availability of favored seeds (especially thistle); they also use thistle down to line their cup-shaped nests. While adults feed on both seeds and insects, the nestlings rely on a fresh crop of soft, immature seeds (hence the importance of timing).
Most species that inhabit hot, dry environments concentrate their activity during the morning and late daylight hours, retiring to cool, shaded areas during the heat of the day. But when breeding season arrives, these finches seem oblivious to the conditions; some instincts are stronger than others!
This summer, a flock of lesser goldfinches has settled at our Littleton, Colorado, farm for the first time. Common across the foothill canyons and shrublands, they are much less common on the adjacent Piedmont and we are about five miles from the base of the mountains. For the past few days, the colorful males have been singing from dawn to dusk, indicating that their breeding season is underway. Like their cousin, the American goldfinch, this western species nests in the summer, timing the process with the peak availability of favored seeds (especially thistle); they also use thistle down to line their cup-shaped nests. While adults feed on both seeds and insects, the nestlings rely on a fresh crop of soft, immature seeds (hence the importance of timing).
Most species that inhabit hot, dry environments concentrate their activity during the morning and late daylight hours, retiring to cool, shaded areas during the heat of the day. But when breeding season arrives, these finches seem oblivious to the conditions; some instincts are stronger than others!
Wednesday, July 16, 2008
March of the Collared Dove
The Eurasian collared dove, a native of India and the Middle East, had spread into Europe by the early 1900s; within another fifty years, it was living and breeding as far north and west as Scandinavia and Great Britain. Released in the Bahamas in 1975, this prolific bird invaded South Florida by the early 1980s and quickly spread through the Southeastern States. Today, small populations have been found as far west as California.
It is now clear that this hardy dove is rapidly becoming a common, widespread resident of North America, matching the success of the maligned European starling. Collared doves were first reported in southeastern Colorado in 1996 and quickly colonized most towns across the State's eastern plains. Sizable populations began turning up in Front Range cities over the past few years and, for the first time this summer, I encountered a breeding pair on our Littleton farm.
Larger than mourning doves, this immigrant may have a negative impact on native bird populations though evidence is lacking to date. Concerned that the collared dove may be a problem in agricultural areas, the Colorado Division of Wildlife has established a Eurasian collared dove hunting season from December through February, with no bag limit; this is in addition to the standard September-October dove season. The winter hunt will occur after the native doves have moved south of Colorado, thereby minimizing impact on those species; the hardy collared dove does not migrate but, like most doves, gathers in large flocks during the colder months.
It is now clear that this hardy dove is rapidly becoming a common, widespread resident of North America, matching the success of the maligned European starling. Collared doves were first reported in southeastern Colorado in 1996 and quickly colonized most towns across the State's eastern plains. Sizable populations began turning up in Front Range cities over the past few years and, for the first time this summer, I encountered a breeding pair on our Littleton farm.
Larger than mourning doves, this immigrant may have a negative impact on native bird populations though evidence is lacking to date. Concerned that the collared dove may be a problem in agricultural areas, the Colorado Division of Wildlife has established a Eurasian collared dove hunting season from December through February, with no bag limit; this is in addition to the standard September-October dove season. The winter hunt will occur after the native doves have moved south of Colorado, thereby minimizing impact on those species; the hardy collared dove does not migrate but, like most doves, gathers in large flocks during the colder months.
Tuesday, July 15, 2008
Vertical Birding
One of the many good things about living at the base of a mountain range is that a whole series of life zones lie within a short distance. Each life zone has its own unique population of flora and fauna and, for the naturalist, there's nothing more inviting. Birders are especially rewarded by such geography and the Colorado Front Range is certainly one of the better bird watching areas in the country.
Facing another day in the 90s, I decided to head for higher and cooler terrain, leaving our Littleton farm just before 7 AM. My first stop was at Deer Creek Canyon Park, southwest of Denver; its parking area and lower trails lie within the foothill shrublands at an elevation of 6100 feet (700 feet higher than our farm). There I saw many of the species that typify that zone: black-headed grosbeaks, rufous-sided and green-tailed towhees, lesser goldfinches, rock wrens, lazuli buntings and white-throated swifts, among others. Driving up the Canyon road to U.S. 285, I turned north for a short distance and took the Parmalee Gulch Road to Mt. Falcon Park, which sits at 7800 feet between Turkey Creek and Bear Creek Canyons. This is an excellent area to observe birds of the Transition Zone (Montane) Forest; today was no exception. Among the residents are mountain chickadees, pygmy nuthatches, pine siskins, violet-green swallows, Steller's jays, Townsend's solitaires, western tanagers and both mountain and western bluebirds. The highlight of this stop was a pair of broad-tailed hummingbirds that kept buzzing a loggerhead shrike; perched atop a ponderosa pine, he was apparently too close for their comfort.
Descending to the Bear Creek Valley, I watched a pair of dippers at the Kittredge town park and then headed through Evergreen on Colorado 74. A few miles north of town is the turnoff to Colorado 103, which climbs westward to Echo Lake and Mt. Evans. After passing Elk Meadow, the road winds up through the forest, entering the Subalpine Zone. A large, aspen-lined clearing at 9200 feet is a good place to stop for some birding; this morning I found yellow-rumped warblers, chipping sparrows, mountain chickadees, red crossbills and a pair of pine grosbeaks. Further up, the road skirts the north flank of Squaw and Chief Mountains, providing a spectacular view of the Continental Divide. Picnic areas along this road are always rewarding for birders; gray jays, Clark's nutcrackers and dark-eyed juncos (gray-headed race) were today's primary visitors.
Echo Lake sits at 10,600 feet near the junction with the Mt. Evans toll road. The trees and shrubs around the lake are usually good for Wilson's warblers and Lincoln's sparrows but I took a pass, paid my $10 toll and headed up the highest paved road in the lower 48. At timberline, the Mt. Goliath Bristlecone Pine area is another hotspot for birders; white-crowned sparrows, mountain bluebirds, red crossbills and pine siskins dominated the show today. Another six miles across the scenic tundra (watch for marmots, bighorn sheep and mountain goats) brings you to Summit Lake, tucked in a cirque at 12,830 feet. American pipits are common here and it is one of the best sites in the country to find brown-capped rosy finches (I saw five this morning). Ravens soar along the sheer cliffs, pikas call from the boulder fields and, if you're lucky, you might spot a white-tailed ptarmigan on the flower-laden tundra.
Facing another day in the 90s, I decided to head for higher and cooler terrain, leaving our Littleton farm just before 7 AM. My first stop was at Deer Creek Canyon Park, southwest of Denver; its parking area and lower trails lie within the foothill shrublands at an elevation of 6100 feet (700 feet higher than our farm). There I saw many of the species that typify that zone: black-headed grosbeaks, rufous-sided and green-tailed towhees, lesser goldfinches, rock wrens, lazuli buntings and white-throated swifts, among others. Driving up the Canyon road to U.S. 285, I turned north for a short distance and took the Parmalee Gulch Road to Mt. Falcon Park, which sits at 7800 feet between Turkey Creek and Bear Creek Canyons. This is an excellent area to observe birds of the Transition Zone (Montane) Forest; today was no exception. Among the residents are mountain chickadees, pygmy nuthatches, pine siskins, violet-green swallows, Steller's jays, Townsend's solitaires, western tanagers and both mountain and western bluebirds. The highlight of this stop was a pair of broad-tailed hummingbirds that kept buzzing a loggerhead shrike; perched atop a ponderosa pine, he was apparently too close for their comfort.
Descending to the Bear Creek Valley, I watched a pair of dippers at the Kittredge town park and then headed through Evergreen on Colorado 74. A few miles north of town is the turnoff to Colorado 103, which climbs westward to Echo Lake and Mt. Evans. After passing Elk Meadow, the road winds up through the forest, entering the Subalpine Zone. A large, aspen-lined clearing at 9200 feet is a good place to stop for some birding; this morning I found yellow-rumped warblers, chipping sparrows, mountain chickadees, red crossbills and a pair of pine grosbeaks. Further up, the road skirts the north flank of Squaw and Chief Mountains, providing a spectacular view of the Continental Divide. Picnic areas along this road are always rewarding for birders; gray jays, Clark's nutcrackers and dark-eyed juncos (gray-headed race) were today's primary visitors.
Echo Lake sits at 10,600 feet near the junction with the Mt. Evans toll road. The trees and shrubs around the lake are usually good for Wilson's warblers and Lincoln's sparrows but I took a pass, paid my $10 toll and headed up the highest paved road in the lower 48. At timberline, the Mt. Goliath Bristlecone Pine area is another hotspot for birders; white-crowned sparrows, mountain bluebirds, red crossbills and pine siskins dominated the show today. Another six miles across the scenic tundra (watch for marmots, bighorn sheep and mountain goats) brings you to Summit Lake, tucked in a cirque at 12,830 feet. American pipits are common here and it is one of the best sites in the country to find brown-capped rosy finches (I saw five this morning). Ravens soar along the sheer cliffs, pikas call from the boulder fields and, if you're lucky, you might spot a white-tailed ptarmigan on the flower-laden tundra.
Monday, July 14, 2008
A Natural Inventory
Avid bird watchers are notorious for keeping lists. They compile a life list, a list for the year, day lists and location lists. Such activity is enjoyable, broadens their experience, fulfills their competitive drive and sharpens the skills so important to their hobby.
I recommend that amateur naturalists also develop the habit of keeping lists; an inventory of plants and animals on your property is perhaps the best project. Regardless of the size of your yard, you will soon be amazed by the variety of trees, shrubs, wildflowers, birds, amphibians, reptiles and mammals that populate your inventory. Truly committed participants could include weeds, grasses, fungi, insects and other invertebrates. New species are added over time as they drop by, fly over, wander in or germinate.
The production of this inventory will provide many hours of entertainment, introduce you to new species and increase your awareness of both the diversity and interdependence of life forms that inhabit your personal ecosystem. Hopefully, this will inspire your interest in all of Earth's species and encourage your support for conservation programs across the globe.
I recommend that amateur naturalists also develop the habit of keeping lists; an inventory of plants and animals on your property is perhaps the best project. Regardless of the size of your yard, you will soon be amazed by the variety of trees, shrubs, wildflowers, birds, amphibians, reptiles and mammals that populate your inventory. Truly committed participants could include weeds, grasses, fungi, insects and other invertebrates. New species are added over time as they drop by, fly over, wander in or germinate.
The production of this inventory will provide many hours of entertainment, introduce you to new species and increase your awareness of both the diversity and interdependence of life forms that inhabit your personal ecosystem. Hopefully, this will inspire your interest in all of Earth's species and encourage your support for conservation programs across the globe.
Sunday, July 13, 2008
Plates and Continents
Amateur geologists often assume that the continental and oceanic plates coincide with the observable physical geography. In fact, most of the tectonic plates harbor both land and sea areas, which are merely surface features on the thick, underlying plates. For example, there is no Atlantic Plate; rather, this ocean is opening along the mid Atlantic Ridge and the crust formed on either side becomes part of the bordering Continental plates (i.e. this ridge is a rift between the North American and Eurasian Plates and between the South American and African Plates).
Land associated with a particular Continent does not always lie on that Continental Plate. The North American Plate, for example, stretches from the middle of the North Atlantic to the Pacific Coast; however, its northwestern extension runs across the northern edge of the Pacific Ocean, taking in the Aleutians, the Bering Sea, the northern islands of Japan and the eastern portion of Siberia. On the other hand, Southern California lies on the Pacific Plate but will eventually join the North American Plate after a long journey to Alaska. India, part of Asia on the map, actually sits on its own plate and Australia's plate runs beneath most of the Indian Ocean, a swath of the Southern Ocean, the eastern islands of Indonesia and both the Coral and Tasman Seas.
Since most earthquakes and volcanoes are associated with friction, compression and subduction along plate margins, it is important to know where these margins are located. More often than not, they do not correspond with what we see on the map!
Land associated with a particular Continent does not always lie on that Continental Plate. The North American Plate, for example, stretches from the middle of the North Atlantic to the Pacific Coast; however, its northwestern extension runs across the northern edge of the Pacific Ocean, taking in the Aleutians, the Bering Sea, the northern islands of Japan and the eastern portion of Siberia. On the other hand, Southern California lies on the Pacific Plate but will eventually join the North American Plate after a long journey to Alaska. India, part of Asia on the map, actually sits on its own plate and Australia's plate runs beneath most of the Indian Ocean, a swath of the Southern Ocean, the eastern islands of Indonesia and both the Coral and Tasman Seas.
Since most earthquakes and volcanoes are associated with friction, compression and subduction along plate margins, it is important to know where these margins are located. More often than not, they do not correspond with what we see on the map!
The American Antelope
Pronghorns are common across the High Plains, from the western Dakotas to Mexico, and on sage grasslands of the Intermountain West. Natives of North America, they are the sole remaining species of a family that included up to 13 members during the Tertiary Period and Pleistocene Epoch. Most paleontologists believe that pronghorns are not directly related to Old World antelopes and some feel that they are more closely aligned with cattle, sheep and goats. Indeed, like bovids, they have a horn composed of a keratin sheath that overlies a bony core; however, unlike bovids, the pronghorn's sheath is branched (in males) and is shed each year.
Once numbering over 40 million individuals, the pronghorn population declined dramatically throughout the 1800s and early 1900s due to over hunting and the fencing of rangelands. Unable to leap over fences, many starved when they were prevented from migrating during periods of heavy snow. Pronghorns are otherwise well equipped to withstand the harsh winters that typify most of their range; though relatively slender animals, they have a dense undercoat and their outer hairs are hollow, providing superb insulation.
Male pronghorns are territorial from late spring through early fall and gather a harem of up to 20 females; younger males travel about in bachelor herds and occasionally challenge the breeding males, often to their own detriment. Breeding occurs in early autumn and females give birth (usually to twins) in early summer. The young are kept hidden for several weeks and, by then, are able to outrun coyotes, their primary predator; as adults, they will become one of the fastest mammals on Earth, able to reach speeds of 70 miles per hour. In winter, pronghorns congregate in large herds, feeding on the lee side of mesas and roaming about to find open forage.
Once numbering over 40 million individuals, the pronghorn population declined dramatically throughout the 1800s and early 1900s due to over hunting and the fencing of rangelands. Unable to leap over fences, many starved when they were prevented from migrating during periods of heavy snow. Pronghorns are otherwise well equipped to withstand the harsh winters that typify most of their range; though relatively slender animals, they have a dense undercoat and their outer hairs are hollow, providing superb insulation.
Male pronghorns are territorial from late spring through early fall and gather a harem of up to 20 females; younger males travel about in bachelor herds and occasionally challenge the breeding males, often to their own detriment. Breeding occurs in early autumn and females give birth (usually to twins) in early summer. The young are kept hidden for several weeks and, by then, are able to outrun coyotes, their primary predator; as adults, they will become one of the fastest mammals on Earth, able to reach speeds of 70 miles per hour. In winter, pronghorns congregate in large herds, feeding on the lee side of mesas and roaming about to find open forage.
Saturday, July 12, 2008
Visual Pollution
As the political season gets underway, candidate signs are popping up all over Columbia. Some lawns host four or five candidates while others have several signs for the same individual. Large banners adorn the major intersections and smaller signs are affixed to cars and phone poles. Well-financed candidates smile down from interstate billboards and even scenic, country barns are plastered with names and slogans. To imagine that this visual pollution actually translates into votes is truly disturbing.
Then there's the permanent gauntlet of billboards along I-70. For a State with as much natural beauty as Missouri, the Government seems to be oblivious to these hideous displays. While other States are having them removed, Missouri condones new, monstrous structures that highlight the ads. Given that a significant percentage are rented by Adult Video stores, visitors and travellers may easily misinterpret the State's "Show-Me" nickname.
Conservation efforts should be directed at landscape as well as at habitat, species and natural resources. Though I vote in Colorado, I would gladly campaign for someone who wants to eliminate billboards and political signs in Missouri!
Then there's the permanent gauntlet of billboards along I-70. For a State with as much natural beauty as Missouri, the Government seems to be oblivious to these hideous displays. While other States are having them removed, Missouri condones new, monstrous structures that highlight the ads. Given that a significant percentage are rented by Adult Video stores, visitors and travellers may easily misinterpret the State's "Show-Me" nickname.
Conservation efforts should be directed at landscape as well as at habitat, species and natural resources. Though I vote in Colorado, I would gladly campaign for someone who wants to eliminate billboards and political signs in Missouri!
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