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Showing posts from August, 2011

Escape to North Park

Not facing any major problems on the farm this trip, I decided to visit North Park, my favorite area in Colorado. Drained by the North Platte River and its high country tributaries, this broad basin, covered with sage grasslands, hay fields and cattle ranches, is laced with ribbons of willow thickets and riparian woodlands. Indeed, North Park is known to many Coloradans as the site where moose were reintroduced in the late 1970s; since that time, those large herbivores have thrived, spreading across the Continental Divide to the Upper Colorado and Fraser River Valleys (and beyond) and transplanted to other areas of Colorado by Division of Wildlife biologists.

Offering scenic, uncluttered landscape, broad vistas, abundant wildlife and traffic-free roadways, North Park takes the visitor back to an earlier period in the history of the Mountain West, before large, congested cities, interstate highways and tourist resorts changed the character of the region. Bordered by the high walls o…

Evicting the Hunter

What first drew my attention was the frenzied squabbling of house finches in a large elm near the back of our property. As I grabbed my binoculars to check out the cause for their alarm, the high pitched calls of lesser goldfinches joined the protest. Then, always looking for a good fight, a group of blue jays drifted in and their raucous voices soon echoed across the farm.

Expecting to find an owl roosting in the clump of trees, I headed back for a closer look. My approach was the final straw and a large Cooper's hawk bolted from cover, heading for another shade tree. A comical parade followed in his wake, including the finches, the blue jays and, to my amusement, a pair of broad-tailed hummingbirds, tiny but courageous. A second round of protest ensued, sending the raptor away for good.

Like other accipiters, Cooper's hawks hunt by stealth, hoping to snare an unwary songbird while zig-zagging through forest or open woodlands. Unless the initial attack is successful, th…

Our Resident Mule Deer

A young doe mule deer has lived on our Littleton, Colorado farm over the past year and, this summer, presented us with a spotted fawn. Likely born in June, it did not make an appearance until July and has since bounded around our property, bleating like a lost lamb if it looses touch with its mother. The fawn will continue to nurse and keep its white spots until late summer and will then remain with mom until she is ready to deliver once again; female mule deer usually produce a single fawn with their first pregnancy but thereafter give birth to twins or, occasionally, triplets.

Mule deer are common from the High Plains to the Pacific Coast and from southeast Alaska, British Columbia and Alberta southward into Mexico. Favoring open woodlands and rocky, shrub-covered hillsides, they are easily distinguished from white-tailed deer by their large ears, stocky build and black-tipped tail. Browsers, mule deer feed on a wide variety of plant material including buds, twigs, leaves, fruit…

The Human Era

When the Earth formed, 4.6 billion years ago, the Universe was already 9 billion years old; in other words, the Universe is three times as old as our home planet. For Earth's first billion years there was no life on the gradually cooling crust or in the primordial seas; then, some 3.6 billion years ago, bacteria-like organisms evolved, most likely in shallow, coastal waters or at "hot-smoker" vents along the mid oceanic ridges. It would be another 3.2 billion years, about 400 million years ago (MYA), that some plants and animals began to leave the ocean to colonize the land.

While the first mammals appeared in the Triassic Period, about 200 MYA, ancestral primates did not appear until the Paleocene Epoch, some 60 MYA. Another 52 million years would go by before hominids (the genus to which we belong) split from chimpanzees and man would not walk the Earth until 150,000 years ago (per the earliest estimate). Roaming about and living in small clans for most of our hist…

Irene's Welcoming Party

After several uneventful years and a slow start to the current season, the hurricane stuntmen from the Weather Channel have taken up posts along the East Coast, from the Carolinas to New England, ready to bring us eyewitness reports on the devastation wrought by Hurricane Irene. Now churning off the Georgia shore, the storm is forecast to move northward across eastern North Carolina and then sweep across the heavily populated corridor of the Northeast. While Irene has weakened to a Category 2 storm, her wind field is very broad and storm surge is the major concern, potentially bringing catastrophic flooding to coastal areas.

With bags packed since the first of June, the weather stuntmen (and stuntwomen) are waiting for the opportunity to stand in the wind and rain while, at the same time, are admonishing coastal residents to heed warnings and evacuate the region. If luck holds, they will be in the right spot to endure the brunt of the storm and, if their antics are dramatic enough,…

Powder River Basin

On my recent journey through Nebraska and eastern Wyoming, I was amazed at the number of coal trains that were streaming eastward; each more than a mile long, the trains were spaced by no more than a few miles. Originating at surface mines in the vicinity of Gillette, Wyoming, this caravan delivers a million tons of coal per day to power plants across the central and eastern U.S.

The Powder River Basin is defined by both its geography and its geology. Covering most of northeast Wyoming and part of southeast Montana, the basin stretches between the Bighorn Mountains of north-central Wyoming and the Black Hills of western South Dakota. Its southern border is the topographic divide between the North Platte watershed, to the south, and the watersheds of the Powder and Cheyenne Rivers to the north; more northern parts of the basin are also drained by the Tongue and Little Missouri Rivers. Geologically, the Powder River Basin is a broad bowl of Precambrian basement rock that gradually f…

Crescent Lake NWR

Crescent Lake NWR, in Nebraska's western panhandle, is certainly one of our more remote National Wildlife Refuges. Take your pick: 28 miles north of Oshkosh (on US 26, northwest of Ogallala) via a winding, sand-gravel road or 28 miles south of Lakeside (on Route 2, east of Alliance) via a single lane of asphalt; during my three hour tour I encountered only a refuge employee in his pickup and the driver of a cattle truck. Whatever route you take, the visit will be well worth your effort (just make sure you have plenty of gas in the tank).

Stretching across 46,000 acres in the westernmost section of Nebraska's famous sandhills ecosystem, Crescent Lake National Wildlife Refuge protects a chain of lakes and wetlands that lie in valleys between the grass-covered dunes. Established in 1931, the refuge provides nesting habitat, wintering grounds or a migration reststop for at least 279 bird species. Nesting birds of note include eared and western grebes, American bitterns, tundra …

The Eastern U.S. Quake

Since we tend to associate earthquakes with active plate margins, as occur along the Pacific Rim, in southern Asia and in the Mediterranean, many Americans along the Eastern Seaboard and Midwest were surprised by today's quake, centered in Virginia. But the truth is, there are few places on Earth (if any) that are immune to earthquakes.

Indeed, both New England and the Southeastern Piedmont are, geologically speaking, a puzzle of exotic terrains, plastered to the "stable" craton during the Precambrian and early Paleozoic Eras, hundreds of millions of years ago; for that matter, the craton itself has old suture lines from the earliest days of continent formation. Though relatively quiescent when compared to the active faults of the Pacific Rim, these cemented pieces remain under pressure as the Atlantic continues to open and both subduction and lateral compression occur along the West Coast. Minor readjustments go unnoticed but more powerful slips, especially when rela…

A Road Less Traveled

Heading back to Colorado, I decided to take a different route from Columbia since the landscape along I-70 has long been committed to memory. The alternative, hardly off-the-beaten-path, was to take I-29 north from Kansas City and then I-80 west from Omaha.

Driving north on I-29, my decision was rewarded by a spectacular lightening display over eastern Kansas. Just north of Mound City, Missouri, flooded fields began to appear, attracting huge flocks of egrets and white pelicans; then, at Rock Port, I-29 was closed almost all the way to Council Bluffs, the victim of persistent flooding along the Missouri River. A one hour detour took us across the hills of northwest Missouri and southwest Iowa, carpeted with crop fields and studded with wind farms. After finally crossing the Missouri at Omaha, I soon crossed the Platte River as well; though some sandbars broke the surface, the Platte was full and sluggish, presumably due to backup from the Missouri River, just downstream.

I would n…

Morning Nighthawks

Over the past week, I have noticed an increasing number of nighthawks on my walks to work, flapping and calling in the cool morning air. An obvious explanation is that the days are waning; two months after the summer solstice, I am now heading out into the faint light of dawn. Since nighthawks are crepuscular, hunting for flying insects at dawn and dusk, their morning routine has shifted with the diminishing period of sunlight.

Another reason is that these fair-weather birds are getting restless as their fall migration rapidly approaches. Now that the day length is comparable to that of late April, when they begin to arrive in North America, they likely sense that it's nearly time to leave. Indeed, large flocks of nighthawks will begin to circle southward in the coming weeks, ensuring that they escape to South America before the chilly nights of autumn kill off their prey.

As an observor who has lived at the same general latitude for my entire life, I have always been fond of …

North American Porcupines

Favoring mixed woodlands, the North American porcupine is found from Alaska to New England, southward through the Appalachians (to Tennessee and Virginia), across the Upper Midwest and throughout the Western U.S., from Canada to Mexico; prone to wander, these large rodents may also be encountered along wooded valleys of the Great Plains. Solitary for much of the year, porcupines mate in early autumn and a single kit is born in mid spring; though it will nurse for several months, the newborn is able to forage soon after birth and remains with its mother through the summer.

Sporting a dense undercoat with thick guard hairs, the porcupine is best known for the hollow, barbed quills that cover most of its body, an effective defense against many predators; those carnivores that feed on porcupines, including coyotes, fishers and bobcats, learn to attack their face or abdomen, the only areas devoid of quills. A nocturnal life style and the habit of resting in trees during the day also offe…

The Largest Fish on Earth

Compared to its marine cousins, the whale shark, the largest fish on Earth, is a relative newcomer to the ocean ecosystems of our planet. While ancestral sharks and boney fish appeared in the Devonian Period, some 375 million years ago (MYA) and modern sharks arose in the Jurassic (160 MYA), current fossil evidence suggests that whale sharks did not evolve until the early Tertiary Period, about 60 MYA; ironically, this was the same time that their unrelated namesake, the mammalian whales, where returning to the sea.

Solitary for much of the year and known for their long migrations, whale sharks favor tropical and subtropical seas where they filter-feed near the surface, scooping in plankton, krill, small squid and small fish with their wide mouths. They do congregate at certain feeding grounds during specific times of the year, drawn by the seasonal spawning of coral or by plankton blooms; perhaps the most famous whale shark rendevous is at the Ningaloo Reef, off the west coast of A…

Geology of Australia's Blue Mountains

The beautiful city of Sydney, Australia, sits on a thick slab of Triassic Hawkesbury sandstone, some 200 million years old. Below this bedrock are older Triassic sediments, shales, mudstones and conglomerates of the Narrabeen Group. All of these deposits, swept into the Sydney Basin by ancient rivers, lie atop Permian strata; containing seams of coal, these latter rocks were emplaced about 250 million years ago, when Earth's land masses had merged into the mega-continent of Pangea.

Just west of the Sydney metropolitan area are the scenic Blue Mountains, a broad, dissected plateau that rose during the Jurassic Period, some 170 million years ago, when Australia was still part of Gondwanaland. The geologic strata of the plateau is identical to the bedrock below Sydney; Triassic sandstone, capped at high points by Miocene basalt, forms massive cliffs which sit atop the older Narrabeen Group and underlying Permian deposits. Metamorphosed Paleozoic rock, from the Silurian and Devoni…

Glacial Lake McConnell

Near the end of the Pleistocene, about 11,800 years ago, a massive lake formed across the Northwest Territories of Canada, extending southward into northeast Alberta and northwest Saskatchewan. Occupying a broad basin between the mountains to the west and the retreating Wisconsin Glacier to the east, its shape and size changed continuously, a balance between the inflow of meltwater and evolving drainage patterns due to glacial deposits, ice dams and periodic floods. The maximum extent of Lake McConnell, reached about 10,500 years ago, was 210,000 square kilometers (about 2/3 the size of glacial Lake Agassiz, to its southeast).

Inflow to Lake McConnell came primarily from the lobes of the continental ice sheet but also from mountain glaciers to the west and directly from Lake Agassiz via a corridor now occupied by the Clearwater and lower Athabasca Rivers; indeed, geologic evidence suggests that these large glacial lakes were intermittently connected and that water flowed in either d…

Gust Fronts

The tragedy at the Indiana State Fair this weekend, in which at least five persons were killed, was caused by a gust front. As many of us have surely noticed, the strongest winds from an advancing line of thunderstorms often arrive before the rain and lightening; caught off-guard, those killed or injured in Indiana may have been waiting for the rain before seeking shelter.

Thunderstorms generally form just ahead of an approaching cold front, drawing in the warm, moist air that lies in their path. Swept into the upper atmosphere, this cargo of moisture precipitates and plunges to the ground as heavy rain within the storm. Rain-cooled air accompanies this rainfall and, upon striking the ground, is forced outward in all directions; in advance of the storm, these high velocity winds produce a gust front, often reaching 60-70 mph, which arrives before the storm itself. A shelf cloud signals the presence of this rapidly moving, cold air, as warm, humid air is displaced above it, creatin…

An Evening Buffet

Granted a mild, sunny evening, we headed down to the Forum Nature Preserve, a local, prairie-wetland refuge that we ignored in recent weeks due to the oppressive heat and humidity. In our absence, the prairie grasses had grown to five feet or more and were now adorned with the golds and purples of late summer: goldenrod, yellow coneflowers, black-eyed susans, thistles and blazing star. Indigo buntings sang from atop the prairie saplings while goldfinches and yellow-billed cuckoos foraged across the woodland border.

But the highlight of this evening was at the large seasonal lake, which, following two months of excessive heat, had nearly evaporated, leaving a broad, shallow, meandering pool. Frogs and turtles peered from the deeper areas and small fish splashed about, desperate to find a path to safety. Taking advantage of this evening buffet, great blue and green-backed herons, stalked the shallows, feasting on the hapless victims, while, along the expanding mudflats, killdeer, s…

Backyard Crustaceans

Mention crustaceans and most of us think of aquatic creatures such as lobsters, crabs, shrimp and crayfish. But, unless you reside in an arid environment, you have many crustaceans in your own backyard.

Pill bugs, known affectionately as rollie pollies, have segmented bodies like their aquatic cousins but have the unique ability to curl into a tight sphere when threatened. Since they, like other crustaceans, breathe through gills, they must remain in moist areas and are typically found beneath logs, rocks, leaf litter or man-made structures; they might also be encounterd in the moist recesses of your garage or basement. Pill bugs feed on a variety of organic matter, such as rotting vegetation and carrion, and thus play an important role in recycling nutrients; while they also feed on living plants, they are rarely a problem for gardeners.

After mating, the female pill bug produces up to a hundred eggs or more, which are carried in a brood pouch for almost a month. Once these eggs …

The Suburban Hibiscus

As the color of spring and early summer begins to fade and the greenery looses its luster, Hibiscus syriacus, commonly known as Rose of Sharon, begins to bloom, adorning the suburban landscape through early autumn. Late to leaf out in the spring, this Asian shrub produces large, showy flowers after most cultivated plants have already gone to seed.

Favoring full sun or partial shade, this plant is drought tolerant and thrives in the dry, sunny climate of the Front Range; we have multiple cultivars on our Littleton farm, with flower colors ranging from white to pink to light blue. Beyond providing a colorful display, the flowers of Hibiscus syriacus attract hummingbirds, butterflies and other insects, and are thus especially appealing to the backyard naturalist.

Seed pods, which overwinter on this shrub, contain numerous, fuzzy seeds that, in moist, warm, climates, can be a nuisance, yielding a forest of seedlings each year; this is less of a problem in more northern or semiarid regio…

The Tree Fox

Favoring woodlands, the gray fox is found east of the Great Plains, from southern Canada to the Gulf Coast, along the Pacific Coast, from British Columbia to Mexico and in the American Southwest, from Colorado to Arizona to Texas; they also inhabit Mexico, Central America and the northern countries of South America. Sporting a pepper-gray coat, fringed by rust-colored fur on its neck and sides, and a bushy tail with a dark dorsal stripe and black tip, this fox has a stockier build and shorter legs than the more common and widespread red fox. Its most unique trait, however, is its ability to climb trees, one of only two canines in the world to do so.

Equipped with sharp claws, the gray fox will climb trees to escape predators (coyotes, feral dogs), to hunt for food (birds, eggs, berries) or simply to lounge on a broad limb; this woodland fox will also use tree cavities on occasion, denning up during severe weather or raising its kits there. Primarily nocturnal, the gray fox may be e…

Nature's Birthday Gift

Turning 61 is hardly a milestone but Mother Nature has sent along a magnificent birthday gift, the first stretch of mild weather in months. Walking to work in a cool, east breeze, I felt energized and noticed the same effects on our neighborhood wildlife; cottontails scampered across the lawns, birdsong was more intense, a trio of young morning doves splashed in a roadside puddle and a cloud of restless starlings wheeled across the pink, morning sky.

Fortunately, unlike in recent weeks, this morning chill will not give way to a hot, humid afternoon; our high is expected to remain in the mid 70s F and, for the next week, maximum temperatures are forecast to stay below 85. This dramatic change, courtesy of a Canadian front, will benefit most of the country, from the Pacific Northwest to the Mid-Atlantic region but the dome of heat and drought will continue to plague most of Texas.

No doubt, summer heat will return before the glory of autumn sweeps across the Heartland but I, for one, …

Wall Street & Somalia

Tuning into the PBS News Hour last evening, one of the few television shows of any value, I watched two stories that highlighted the vast and growing gulf in human society. The first focused on the meltdown in the stock market, triggered by upperclass tax cuts, futile wars, the banking crisis and recent bickering in Congress over the National Debt. The second, in sharp contrast, revealed the horror in southern Somalia, where a prolonged drought and vicious militias have sent hordes of starving families across the border, to a massive refugee camp in Kenya; some 30,000 Somali children have died from illness and starvation over the past few months.

While these crises are worlds apart, their juxtaposition in the news highlighted the tremendous variance in human lifestyles, a phenomenon unseen in any other species. The comfortable life of an investment banker, with his mansion, penthouse and yacht, is so far removed from that of a starving Somali child that it takes some effort to real…

Ritual of Exclusion

It's that time of year in Columbia. Sororities and fraternities have initiated their annual Rush, a noble tradition to some, just another ritual of exclusion to many.

Human society is awash with opportunities for beautiful, rich and well-connected individuals, assuming they are of the appropriate race, gender, nationality, religion and political party. Discrimination and intolerance, ingrained in childhood, are universal, products of ignorance, fear, greed and mysticism.

While most of us support the concept that individuals should be rewarded for their talent, hard work and dedication, we despise the human tendency to selectively exclude persons based on traits over which they have no control. Assumptions derived purely from physical appearance are often false and one's personal beliefs, unless flaunted or injurious to others, should be of no consequence. Perhaps it is our tribal instinct that lies behind this ritual of exclusion; if so, we need to evolve beyond its influe…

Flocking Season

By August, most North American birds have completed their breeding cycle; there are exceptions, of course, including goldfinches that take advantage of the late summer thistle crop, but many bird families are beginning to merge into their large flocks of autumn and winter. These congregations may be for the purpose of migration or, in the case of our permanent residents, a means to improve survival during the lean months of the year.

Out in the countryside, mixed flocks of swallows gather on power lines, squadrons of mourning doves roam the crop fields and red-winged blackbirds move about the wetlands in large, noisy crowds. Water birds, including gulls, terns, egrets, white-faced ibis, white pelicans and shorebirds gather at favored staging sites, preparing for their journey to the south. In both urban centers and farm communities, grackles and starlings have reformed their massive armies, ready to scavenge the bounty that nature and human society have produced.

Up north, the wate…

Rock Creepers

Having a low center of gravity and equipped with relatively large, sharp-toed feet, canyon wrens comfortably negotiate the steep walls of canyons and rock formations throughout the western U.S, southwest Canada and Mexico. There they creep across the surface, scouring crevices for insects with their flattened heads and long, thin bills.

Inconspicuous to the casual hiker, canyon wrens are more often heard than seen. Their melodious, cascading song frequently rings through the canyon but these hunters prefer the shadows and their rusty-brown plumage blends with the rocky habitat. Monogamous for the breeding season (and perhaps for a year or more), canyon wrens build a cup-shaped nest of twigs and dried vegetation which is placed within a rock crevice; 4 to 6 eggs are incubated by both parents who also share the feeding duties.

Unlike their cousin, the rock wren, these birds do not migrate south for the winter; rather, they descend to lower elevations or move to more sheltered areas d…

The Nature of Bamboo

Though often referred to as bamboo "trees," these widespread plants are actually members of the grass family. Represented by more than 1400 species across the globe, bamboo is most abundant and most heavily utilized in southern and eastern Asia; however, native species grow on all continents except Europe and Antarctica. North American bamboo, known as river cane or canebreak, was once common from the Chesapeake Bay to the Ohio River Valley and southward to the Gulf Coast; scattered pockets remain but most stands have been cleared for agriculture.

Initially sprouting from seed, bamboo spreads via underground rhizomes, resulting in large, dense colonies of genetically identical plants; most species are found in tropical areas but some are cold tolerant and grow in the Temperate Zone. Flowering and subsequent seed pod production occurs simultaneously throughout the colony but such events are often widely spaced, occuring every 40-100 years or more in the largest species. S…

Phoenix, Missouri

As I walked home late yesterday afternoon, the temperature in Columbia was 108 degrees F, the highest I have ever experienced in the American Midwest. A southwest wind was bringing hot, relatively dry air into the Heartland as the high pressure dome had dropped a bit to our southeast, placing Central Missouri along its northwest edge.

Highs above 100 degrees F are unusual in humid areas such as Florida and the Gulf Coast since water vapor decreases the density of the air and caps its capacity to retain heat. Dry air, typical of the American Southwest and other desert regions, is dense and is thus capable of reaching temperatures well above the century mark. Indeed, yesterday's blast furnace was remniscent of past summer visits to Phoenix; by 9 PM, the local temperature was still 98 F and, at dawn this morning, it had only dipped to 78.

Fortunately, a "cold front" will keep us in the mid 90s today and, by the middle of next week, highs are expected to remain in the 80s…

Geology of Mt. Etna

The interaction of the African and Eurasian Plates is complex, with areas of compression, subduction and transform-faulting (lateral slippage and scraping). Mt. Etna, Europe's tallest and most active volcano, rises near the east coast of Sicily and has developed along a subduction zone, where the African Plate is dipping beneath the Eurasian Plate; there is some debate among geologists whether its formation is strictly due to melting of the African Plate as it subducts or whether a fracture developed within the plate, producing a local hotspot.

Towering to almost 11,000 feet, Mt. Etna began to form about 500,000 years ago, initially as a shield volcano that built up from repeated flows of basalt; very late in the Pleistocene, about 35,000 years ago, it converted to a stratovolcano, rising to much greater heights. Several eruptive craters are clustered near its summit but many more are scattered along its flanks; indeed, a massive eruption on its eastern slope produced the Valle …