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Showing posts from November, 2008

Winter Weed Control

Throughout the colder months, millions of weed seeds cover our flower beds, lawns and fields; millions more lie beneath the thickets and woodlands. Of course, one's definition of "weed" is a bit subjective but even naturalists agree that the seeds of invasive, non-native species are unwelcome components of our ecosystems.

Fortunately, many birds and small mammals consume "weed seeds" and thus play a major role in the control of these plants. In the Midwest, juncos, cardinals, mourning doves, house finches, American goldfinches and a wide variety of sparrows scour the ground for these morsels of energy. Even more are consumed by the huge flocks of starlings, grackles and red-winged blackbirds that roam the winter landscape.

Come spring, there will be plenty left to diversify the foliage but, thanks to the diet of our resident wildlife, their numbers will be kept in check. This natural control is surely preferable to the wholesale use of herbicides, a practice …

Fort Hill State Memorial

The Hopewell Indians, known for their ceremonial earthworks, occupied the Ohio River Valley from 200 BC to 300 AD. Fort Hill State Memorial, in southern Ohio, protects one of their sites and offers a pleasing mix of scenic terrain, broad vistas, geologic features and abundant wildlife.

Located west of Ohio 41, 10.5 miles southwest of Bainbridge, the Memorial stretches along the Baker Creek Gorge and onto a spur ridge of the Appalachian Plateau. Access is provided by eleven miles of trails, which lead through the gorge, along the forested walls and up to the ceremonial fort, 423 feet above the level of the creek. Cliffs of Silurian dolomite line the gorge, where waterfalls and springs produce scenic ice formations during the colder months; in a few areas, this water erosion has carved natural bridges. Higher on the gorge walls, the dolomite gives way to Berea sandstone, Mississippian in age, which caps Fort Hill and other knobs along the valley; the Hopewell used this resistant rock to …

Feeding Groups

Experienced birders know that woodland birds often move about in mixed flocks and that this feeding behavior is especially common during the colder months. One might hike for some distance without seeing (or hearing) any activity and suddenly come upon a large number of birds, usually composed of multiple species. In like manner, the backyard feeder may stand idle for an hour or so and then suddenly become the focus of a roving flock of residential birds.

In the Midwest and eastern U.S., these "feeding groups" usually contain chickadees, titmice, nuthatches, downy woodpeckers, cardinals and a variety of finches. At times, they may also be followed by ground feeders such as juncos, mourning doves and sparrows. This behavior likely reflects both the benefit of group efforts to locate food and improved protection from predators; more eyes offer better detection and the large number of moving targets may confuse the hunter.

Avid birders know that such feeding flocks offer imme…

On Behalf of all Species

Those of us who care about wildlife and the health of natural ecosystems know that they are under constant threat from the forces of development, pollution and exploitation. We also understand that the only way to sustain the biologic diversity of this planet is to protect wilderness, in all of its forms. Vast and undisturbed forests, deserts, wetlands, prairies and marine ecosystems are vital to the welfare of Earth's species, including humans.

On this day of Thanksgiving, it seems appropriate to acknowledge the work of those many individuals and organizations across this globe that are devoted to wildlife conservation and open space protection; some of these groups are listed in the right column of this blog. On behalf of the varied creatures that inhabit our planet, I thank them for their efforts and urge others to support them.

Curiosity and Fear

Man is a curious creature. Were he not, our species would have perished in Africa, the victim of overcrowding, malnutrition and disease. Curiosity, the stimulus for adventure and exploration, has take us across the globe and into space. At each step along the way, curiosity had to conquer fear.

The advance of human culture has also been dependent upon our curiosity, which was (and is) the essential ingredient for the scientific revolution. The desire to understand the "how and why" of our complex Universe (and of our place in it) has led to a long string of scientific theories and discoveries. Once again, the steps involved in this process necessitated the courage and curiosity to overcome fear and to take risks.

The knowledge derived from exploration and discovery can induce other fears. Some humans deal with these fears by ignoring or rejecting science-based knowledge. They hide within their simplified view of this world; for them, faith trumps science and curiosity tempts f…

Bright Lights

For those who care to look, there are an endless number of natural spectacles on this planet. But sometimes, it is our vantage point in the Universe that yields the visual splendor.

This week, Jupiter and Venus close in on one another in the southwest sky; this spectacular rendezvous is best observed just after dusk. Their pairing, of course, is just a temporary illusion, produced by our current point of view. In fact, Jupiter, though much larger, is five times further from Earth than is Venus; on the other hand, Venus, orbiting much closer to the sun, is far brighter than Jupiter (both, of course, are merely reflecting light from the sun).

Natural spectacles on Earth make us feel part of a complex yet beautiful ecosystem. Those in the night sky induce wonder and humility. Our magnificent planet is, after all, just another bright light in a vast sea of darkness.

A Cloudless Sky

Over the past decade, I have made numerous road trips between Colorado and Missouri; until today, I cannot recall one in which the entire 800-mile drive was made under a cloudless sky. Becoming aware of this fact during the trip, I started looking for even a hint of clouds on distant horizons; alas, none were seen.

High pressure controlled the entire Great Plains province today, shunting any Pacific moisture into Canada and blocking any flow from the Gulf of Mexico. Under such conditions, the air within the dome sinks, further compressing and drying the air. Since the formation of clouds and showers requires lift, atmospheric conditions within the high pressure dome negate any chance of their development.

In addition to the cloudless sky, evidence of the low humidity was made evident by the rapid evaporation of power plant steam and by the short contrails of commercial jets. Under more typical conditions, we see the long exhaust trails of these planes crisscrossing the sky, often d…

November along the South Platte

It was cool and sunny along the South Platte River this afternoon, marred only by a moderate, upslope haze. The annual waterfowl surge is well underway with a wide variety of ducks on the river and floodplain lakes; buffleheads and green-winged teal were especially common today. Other water birds included pied-billed grebes, American coot, ring-billed gulls, great blue herons and a few killdeer; double crested cormorants, common here during the warmer months, have apparently departed for the south.

Though I didn't spot any bald eagles today, several red-tailed hawks and American kestrels represented the raptors. Flocks of Canada geese, entering their peak season along the Front Range, provided a background chorus while belted kingfishers chattered along the river. As one might expect on a mid day visit, mammals were seldom encountered, represented only by the fox squirrels and a lone muskrat.

Woodland birds were active on this cool afternoon; magpies, northern flickers, downy woodpe…

Townsend's Solitaire

We have owned our Littleton, Colorado, farm since 1990 and, each winter, a Townsend's solitaire has taken up residence from November through March. Attracted by the large, prolific juniper trees, the solitaire is highly territorial, defending his supply of berries from other solitaires and, unsuccessfully, from the larger robins that also enjoy this bounty.

Townsend's solitaires are gray, streamlined thrushes with a prominent white eye ring and buff-colored wing patches; they are mid-sized between blue birds and robins. Throughout the warmer months, they inhabit coniferous forests of the foothills and mountains where they are usually seen alone, flycatching from a dead snag or treetop. Solitaires nest on the ground, choosing a protected site beneath a shrub, fallen tree or rock overhang; four eggs are typically produced and, as with most other thrushes, both parents tend to the nestlings.

As cold nights begin to eliminate their insect prey, these birds switch to a diet of ju…

Oceanic Islands

The islands that we observe in Earth's oceans today were formed by one of three processes: flooding, volcanism or rifting; in some cases, more than one process was involved. Most of the islands near Continental coasts are merely high ground on the continental shelf, cut off from the mainland when sea level rose after the Pleistocene glaciers retreated; Great Britain, Ireland, Newfoundland, Long Island, Sri Lanka and Tasmania are all examples of such islands.

Most oceanic islands are volcanic in origin, having developed in one of three ways. Some develop by volcanism along a spreading ridge, where plates are moving apart and new ocean crust is forming; Iceland and the Azores are prime examples (the Azores occur at a site where three tectonic plates, North American, Eurasian and African, are pulling apart). Hotspot islands, such as the Hawaiian, Galapagos and Cape Verde Islands have developed above a mantle plume, often far from a plate margin. Finally, volcanic island chains for…

Reality Check

Like a massive atmospheric bowling ball, a cold dome of high pressure has rolled into the Northern Plains and our brief summer has been squashed back toward the Southwest. We sit at 28 degrees F this morning and will reach a projected high of 35 this afternoon; that's 30 degrees colder than yesterday and more than 40 degrees colder than the high of two days ago.

Since the center of this frigid dome is still up in Alberta, its surrounding, clockwise winds are coming in from the east, producing upslope conditions along the Colorado Front Range; snow showers, fog and freezing drizzle are forecast for much of the day. Suddenly, it feels like November once again.

Fortunately, this dip in the jet stream is expected to flatten out and the cold air will soon be shunted off to the east. More seasonable conditions will return for the coming week, with highs in the 50s and lows in the 30s. But alas, our fling with summer has ended.

Golden Gate Canyon

The promise of another mild, sunny day sent me off to Golden Gate Canyon State Park, in the foothills northwest of Golden, Colorado. Known for its scenic granite outcrops, abundant wildlife and fabulous trail network, the Park is a popular destination for Front Range naturalists and hikers. Among its resident wildlife are black bear, mountain lions, mule deer and wintering elk.

This morning, I elected to take the Horseshoe Trail, for a gradual, 1.8 mile climb to Frazier Meadow. Rock outcrops just short of the meadow offer scenic panoramas of the Park and are a great spot for a picnic lunch; Mt. Tremont, the centerpiece of Golden Gate, looms to the northwest. On today's hike, I saw the usual mix of foothill birds (mountain chickadees, Townsend's solitaires, Steller's jays, pygmy nuthatches and pine siskins), noisy red squirrels and a few mule deer; no bears or mountain lions today! From the meadow, I was also treated to the flight of a golden eagle as it soared above th…

Summer in November

It feels like summer along the Colorado Front Range today, with high temperatures expected to reach the upper seventies. But, if you open your eyes, you will find that it is still November. The trees and shrubs are mostly leafless and those leaves that still flutter in the breeze have lost their October glory. Most noticeable is the lighting, the effect of the low, seasonal sun angle, which produces long shadows and less intense sunlight.

For those interested enough to notice, the summer songbirds are absent and a mix of winter visitors and permanent residents feed in the thickets and woodlands. Here on our Littleton farm, there are no house wrens buzzing about the brush pile or colorful orioles moving among the mulberries; rather, juncos have arrived to join the chickadees, house finches, flickers, magpies and other regulars. Canada geese, much more common during the colder months, are another sign of the season, their noisy flocks moving about the area from dawn to dusk.

This brief he…

The Osage Orange

It must have been a good year for osage orange trees in eastern Kansas. Their large, globular fruit seems to be especially abundant in the tangled, leafless trees that edge the cropfields and pastures along I-70. Native to the Red River Valley of Texas and Oklahoma, the osage orange was found to be an ideal tree for windbreaks and fence rows and is thus widely planted on the Great Plains; hard, rot resistant wood and interlacing, thorny branches provided natural fencing for early ranchers. The tree, a member of the mulberry family, is also planted as an ornamental in other parts of the country; since it is both drought tolerant and prolific, the osage orange readily naturalizes and can become a nuisance.

The fruit, also known as a hedge apple, develops with a green, nodular surface and remains on the tree until late October or November; by that time, it has taken on a faded yellow color and, adorning the bare woodlands, seems to be a harbinger of the coming holidays. The large glob…

America's Till Plain

Driving across central Illinois, one encounters one of the flattest landscapes in the eastern U.S.; it is a classic till plain. Plowed flat by the Pleistocene glaciers, this region was also covered by a thick veneer of till (pulverized rock and organic debris) as the ice sheets retreated toward Canada. In concert, meltwater streams began to mold the plain, draining toward the Ohio and Mississippi Rivers; since they were eroding soft, loosely compacted deposits, these streams meandered, creating broad, shallow valleys that give little relief to the flat plain.

Before white settlers arrived in the Midwest, this vast till plain was covered by tallgrass prairie. Periodic drought, wildfires, high winds and the grazing of massive bison herds maintained the prairie and woodlands were limited to the stream valleys. Today, trees also rise along fence lines and throughout the numerous towns and cities that dot the landscape; the tallgrass of the Prairie State, while protected or reestablishe…

A Day for Crows

A drive back to Ohio in mid autumn can be a pleasant experience; not this time! A storm system, centered over the Great Lakes, brought wind and cold rain to the Midwest today, producing gray skies, low clouds and a damp landscape. Dead leaves, brown or faded yellow, clung to the winterized trees, corn stubble withered in the steady rain and shallow pools dotted the grassy fields. Wild creatures, taking cover in these raw conditions, were few and far between, represented by an occasional red-tailed hawk along the highway, a group of wild turkeys in the Wabash Valley and a lone coyote in southeast Indiana; a notable exception was the large number of crows.

Crows are oblivious to the vagaries of Midwest weather. Today, small flocks scavenged along the Interstate, scoured the crop fields or gathered in the bare timber. Raucous and aggressive, these birds are often maligned but one must admire their fortitude and perseverance. These traits, after all, have ensured their success in a …

Unnatural Lines

When we get the opportunity to view the Earth from aircraft or study photos from space, we notice that something is missing. Having studied geography throughout our years in school, we expect to see boundaries around countries, provinces, states and counties. After all, those lines define our allegiances and play a major role in our own self image.

Nature, of course, pays no attention to these lines. They do not impede migrations, stream flow or weather patterns. Storms and earthquakes move across them and they often have no correlation with natural, geophysical boundaries. Neither do those lines offer protection from the global effects of climate change or pollution.

These human boundaries, the supreme expression of our tribalism, are the equivalent of territorial behavior in other mammals. And while they may serve a purpose in social organization, they foster nationalism, discrimination, mistrust and war. This provincial mindset is also a major obstacle to resolving global issu…

The Walrus and our Climate

The common ancestor of pinnipeds diverged from terrestrial bears during the Miocene Period, about 20-25 million years ago. Today, these semiaquatic mammals are represented by three families: true seals, eared seals (sea lions) and walruses.

Once composed of numerous species inhabiting tropical, temperate and arctic life zones, the walrus family has two surviving members, the Atlantic and Pacific walruses; both are Arctic residents. The Atlantic walrus was once found as far south as Cape Cod but is now restricted to to the Arctic of northeastern Canada, Greenland and northwest Russia. The Pacific walrus, a bit larger and much more numerous, summers on and along the Chukchi and Beaufort Seas but winters south of the Bering Strait; male groups may remain in the more southern areas throughout the year.

Both species rely on ice flows, rocky islands and isolated beaches to "haul out" in order to rest, warm up or to give birth. Walruses breed in late winter and a single calf is born …

Humans in the Americas

Though we evolved in Africa some 125,000 years ago, humans would not reach the Americas for more than 100,000 years. Man spread into Australia by 60,000 years ago and occupied the Mediterranean region about 50,000 years ago but would not set foot in North America until the peak of the Wisconsin glaciation, some 20,000 years ago.

The great majority of human migrants reached the Americas via the Bering Land bridge, which remained open through most of the late Pleistocene; however, DNA evidence suggests that some of these original inhabitants arrived from Europe after hunting their way along the southern edge of the North Atlantic ice shelf. Those crossing from Asia bypassed the North American glaciers via two routes; some (perhaps most) spread southward along the Pacific coast while others followed herds of mammoths and bison through an ice-free corridor east of the Rocky Mountains. Most archaeological evidence indicates that man was south of the glaciated areas by 15,000 years ago an…

First Snows

Walking to work on this cold, November morning, my attention was drawn to the distant, unmistakable call of snow geese. Faint at first, the high-pitched clamour grew louder but they were difficult to find among the high clouds in the predawn light. Suddenly, I saw them, a wavering double-V of migrants, angling to the southeast.

Long a favorite of mine and an inspiration for many naturalists, snow geese are among the last migrants of fall and the first to head north in the spring. Here in Missouri, their numbers will build through mid December but, eventually, most will move on to wetlands along the Gulf Coast and lower Mississippi Valley. By February, flocks will travel north once again, destined for breeding grounds on the Arctic tundra.

More that almost any other species, migrant geese stir the soul of man. Moving high overhead, their vocal flocks symbolize both freedom and determination. If only we could give up our daily troubles and share their adventure!

Hurricane Paloma

The development of a hurricane requires warm ocean water, a hot, humid environment and light, upper-level winds. During the peak of the Atlantic Hurricane Season, which extends from June through mid November, most storms develop from tropical waves that move westward off the coast of Africa. However, early and late in the season, these storms usually form over the warm waters of the Caribbean Sea or Gulf of Mexico; Hurricane Paloma offers a classic example.

After developing in the western Caribbean, Paloma began to drift to the northeast under the influence of an approaching cold front. Moving across open waters and beneath a calm upper atmosphere, the storm strengthened to a Category 4 Hurricane as it ravaged the Cayman Islands and headed for Cuba. Fortunately, just off the southern coast of Cuba, the storm encountered the strong upper level winds of the advancing front; combined with the effects of the island's mountainous terrain, these shearing winds disrupted the storm'…

Winter Songsters

Once the summer residents head south and cold, gray weather invades the Heartland, the sound of birdsong nearly disappears until late February. Peeps and twitters rise from the thickets, the raucous calls of jays, crows and woodpeckers ring through the woodlands, the yank of nuthatches echo through our yards, the hoot of owls greet the dusk and the clamour of geese stirs the soul. But only a few birds bring a cheerful tune to our bleak winter days.

Chickadees, undaunted by the cold and snow, sing their way through the season, keeping hope alive for the rest of us. White-throated sparrows, having summered in Canada, are perfectly comfortable in our winter weather; though their distinctive tune is shorter and less intense than it will be next spring, they refuse to spend the season in silence. Finally, the Carolina wren, while looking out of place in the snowy landscape, is feisty enough to sing any time he wants: winter be damned!

Pinwheel on the Plains

A potent winter storm has been lumbering across the Northern Plains over the past two days. Like a giant pinwheel, the central low pressure is surrounded by strong, counter-clockwise winds; pulling in warm, moist air ahead of the front, these winds force the air to rise and cool as it moves west, dropping heavy snow across the Dakotas. On the west side of the storm, which is now centered along the Minnesota-Wisconsin border, strong, north winds are dragging frigid air down from Canada and, combined with the heavy snow, are producing blizzard conditions across the northern High Plains.

Here in Missouri, on the south edge of the storm, the winds are from the west, ushering in cool, cloudy weather and occasional showers. As the storm moves into the Great Lakes, our clouds will disperse but a steady, northwest wind will augment the chill for the next few days. It is, after all, November and winter is gaining control.

The Nature of Racism

Man evolved in East Africa about 125,000 years ago and, for the first 70,000 years of our existence, virtually all humans were dark-skinned; this trait offered protection from the intense, tropical sun, which characterized their habitat across Africa, southern Asia and Australia. About 50,000 years ago, man began to spread northward, entering temperate regions where solar radiation was reduced by the seasonal change of the sun angle. As has occured in other species, variability in skin pigmentation began to develop among human populations, reflecting an adaptation to the environment via the process of natural selection. Today, a spectrum of skin coloration characterizes our species and further variation will occur due to gene mixing through inter-racial marriages.

Unfortunately, this single human trait, though totally unrelated to other human features and capabilities, has become a rationale for discrimination and persecution. Rooted in ignorance, such beliefs are ingrained in children…

Nature and the Election

As an Independent, I am a social liberal and a fiscal conservative. But, as an environmentalist, I usually support the Democrats and, in this election, there's too much at stake not to do so once again.

Of course, both political parties claim to be concerned about the environment but, in my experience, their reasons and solutions differ dramatically. Conservative Republicans view conservation in the context of outdoor recreation. Favoring industry, development and personal freedom over the protection of natural ecosystems, they often minimize the impact of human culture on the environment. They favor access over wilderness, new roads over mass transit and exploitation over conservation. To them, concerns about global warming, endangered species and habitat destruction reflect the bias of a liberal media. Governed by capitalist principles and a religious mindset, they view the natural world as God's gift to man, his chosen species and the pinnacle of his creation.

After eight yea…

Mid Plate Earthquakes

Most earthquakes originate along the edge of the tectonic plates where compression, friction or subduction occur. Other common sites are along rift valleys or mountain ranges where buried fault lines are especially numerous.

But, on occasion, earthquakes strike in areas where there is little surface evidence of past or recent tectonic activity. Tremors may strike vast plains, rolling farmlands or flat lake country. In such cases, the quake originates deep below the surface, in the basement rock of the tectonic plate, and usually reflects the presence of an old suture line or aborted rift zone. Since covered by thick layers of sedimentary rock and surface deposits, these deep faults, often quiescent for thousands or millions of years, suddenly shift due to pressure change within the plate.

Almost all of western North America was pieced together by small plates and exotic terrains that were welded to the primary North American Plate. These numerous suture lines remain a common source…

Smithville Lake

Smithville Lake is a large reservoir north of Kansas City, Missouri. Stretching north to south above the east wall of the Missouri River Valley, the Lake and its surrounding wetlands are a magnet for migratory waterfowl and early November is an excellent time to visit. Access to the area is via U.S. 169 (north of I-435), on the west side of the Lake, or from Missouri 92 which passes south of the reservoir; the Visitor Center is adjacent to the Dam on Route DD, which loops between the above highways.

Migrant ducks are peaking by November; rafts of diving ducks (redheads, ring-necks, scaup, common goldeneyes, buffleheads, ruddys, canvasbacks and mergansers) gather on deeper waters near the dam while surface feeders (mallards, wigeon, gadwall, shovelers and coot) favor the backwater shallows; the former are often joined by a variety of loons, grebes, gulls and terns though pied-billed grebes prefer the shallower waters. Bald eagles are common here throughout the colder months, peregrine f…

November in Missouri

Despite its reputation for cold, gray, blustery days, November offers its fair share of pleasant weather in Missouri. In most years, the warm afternoons and cool nights of October spill into the first half of the month and persistent cold is unlikely to develop until December.

Beyond the fair conditions, November offers some significant attractions for naturalists. Though the autumn colors are fading, the crisp air and dry trails make conditions ideal for hiking. Yet, perhaps in anticipation of the coming winter, the crowds begin to diminish and the opportunity for solitude increases through the month. At the same time, wildlife, stirred by the autumn chill, become more active (and watchable) and the migration of waterfowl is peaking across the State.

For all of these reasons, November is a great month for outdoor exploration in Missouri. Then again, the other eleven are as well!