Located in the center of the country, at the junction of its three largest river systems, Missouri blends four geophysical provinces: the Glaciated Plain, the Osage Plain, the Ozark Highlands and the Coastal Plain. Exposed bedrock ranges from Precambrian granite to Carboniferous limestones and karst topography, including numerous glades and caves, covers a broad swath of the State.
This geophysical diversity results in a wide variety of plant communities, from cypress swamps to upland forest, to floodplain wetlands and tallgrass prairie. This, in turn, leads to a tremendous diversity of fauna, a fact most recognized by bird watchers. The typical "eastern birds" are common throughout Missouri and its western counties host species typical of the Great Plains; the latter include scissor-tailed flycatchers, upland sandpipers, Swainson's hawks and blue grosbeaks. Southwestern Missouri is home to greater roadrunners, painted buntings and nine-banded armadillos while the southeastern "Bootheel" attracts a mix of wetland fauna more typical of the Southeastern States. The Glaciated Plain of northern Missouri draws winter incursions of Canadian wildlife (such as snowy owls, common redpolls, snow buntings and longspurs) and the migration highways of the Missouri and Mississippi Rivers produce some of the most spectacular congregations of waterfowl on the Continent.
For all of these reasons, one might think of Missouri as the natural centerpiece of America. To those of us who live here, the title seems appropriate.
Wednesday, April 30, 2008
Tuesday, April 29, 2008
Songbird Rest Stops
As they move northward in the spring, most songbirds migrate at night, stopping to rest and feed for a day or two between legs of their journey. En route, many of these travellers must cross large bodies of water, including the Atlantic Ocean, the Gulf of Mexico and the Great Lakes. Finding themselves near or over water in the early daylight hours, they settle down on the closest shoreline and, as one might suspect, some of these coastal areas prove to be excellent birding locations.
Barrier islands along the northern Gulf of Mexico, such as Dauphin Island off Mobile, attract exhausted migrants that have just crossed from Central or South America. In like manner, Cape May, at the southern tip of New Jersey, is a magnet for birds that migrate up the Atlantic Coast. Wooded areas along the southern and northern shores of the Great Lakes always fill with birds during the spring and fall migrations; Cane Creek/Magrish Marsh, east of Toledo, and Point Pelee Provincial Park, on the northern coast of Lake Erie, are two of the more renowned birding hot spots. Late April through mid May is an excellent time to visit these songbird rest stops!
Barrier islands along the northern Gulf of Mexico, such as Dauphin Island off Mobile, attract exhausted migrants that have just crossed from Central or South America. In like manner, Cape May, at the southern tip of New Jersey, is a magnet for birds that migrate up the Atlantic Coast. Wooded areas along the southern and northern shores of the Great Lakes always fill with birds during the spring and fall migrations; Cane Creek/Magrish Marsh, east of Toledo, and Point Pelee Provincial Park, on the northern coast of Lake Erie, are two of the more renowned birding hot spots. Late April through mid May is an excellent time to visit these songbird rest stops!
Monday, April 28, 2008
Midwest Swallows
Six swallow species inhabit the American Midwest during the warmer months of the year. All are graceful fliers and feed primarily on flying insects; this trait makes them especially beneficial to humans but makes them vulnerable to periods of cold weather or heavy rain (since they also feed on berries, tree swallows are least susceptible to these foul weather events).
Tree swallows, identified by their blue-green back, white underparts and slightly forked tail, are the only species to winter along southern U.S. coasts and generally arrive in the Midwest by late March. Migrating in huge flocks, they pair off to look for nest sites in tree cavities or man-made nest boxes. The other five species arrive by late April and, like tree swallows, favor open country with nearby lakes or wetlands.
Barn swallows are easily identified by their deeply forked tail and, as their name implies, usually nest within barns or under their eaves. Bank swallows, smallest of the group, nest in large colonies, digging burrows into the side of riverbanks or quarry walls; their best field mark is a brown band crossing their white chest. Cliff swallows, identified by their squared tail and buff-colored rump feathers, also nest in colonies, often gathering beneath bridges, cliff ledges or the roofs of rural buildings.
Purple martins, our largest and heaviest swallow, have dark purple plumage; the females and immature birds have light gray underparts. Nesting in tree cavities or man-made "martin houses," these birds are often seen in the evening sky, hawking for insects with chimney swifts and common nighthawks. Finally, northern rough-winged swallows, less conspicuous than their cousins, have dull brown backs, a faint brown wash on their chests and slightly forked tails. They nest in pairs or small groups, usually along streams; their nests are placed in the hollows of bridges, in drainage pipes and in crevices on rocky bluffs.
By late summer, swallows begin to form large, mixed flocks, often gathering on power lines in rural areas. Come October, the tree swallows will depart for coastal areas of the southern U.S. and Mexico while the rest will head for Central and South America.
Tree swallows, identified by their blue-green back, white underparts and slightly forked tail, are the only species to winter along southern U.S. coasts and generally arrive in the Midwest by late March. Migrating in huge flocks, they pair off to look for nest sites in tree cavities or man-made nest boxes. The other five species arrive by late April and, like tree swallows, favor open country with nearby lakes or wetlands.
Barn swallows are easily identified by their deeply forked tail and, as their name implies, usually nest within barns or under their eaves. Bank swallows, smallest of the group, nest in large colonies, digging burrows into the side of riverbanks or quarry walls; their best field mark is a brown band crossing their white chest. Cliff swallows, identified by their squared tail and buff-colored rump feathers, also nest in colonies, often gathering beneath bridges, cliff ledges or the roofs of rural buildings.
Purple martins, our largest and heaviest swallow, have dark purple plumage; the females and immature birds have light gray underparts. Nesting in tree cavities or man-made "martin houses," these birds are often seen in the evening sky, hawking for insects with chimney swifts and common nighthawks. Finally, northern rough-winged swallows, less conspicuous than their cousins, have dull brown backs, a faint brown wash on their chests and slightly forked tails. They nest in pairs or small groups, usually along streams; their nests are placed in the hollows of bridges, in drainage pipes and in crevices on rocky bluffs.
By late summer, swallows begin to form large, mixed flocks, often gathering on power lines in rural areas. Come October, the tree swallows will depart for coastal areas of the southern U.S. and Mexico while the rest will head for Central and South America.
Sunday, April 27, 2008
The Hop Hornbeam
A small tree has been growing in a flower bed on the southeast side of our house for ten years or so. Bearing lanceolate leaves with serrated margins, it appeared to be a type of elm, though its identity remained uncertain. This month, for the first time, the tree developed copious, dangling, olive-yellow catkins and, searching through my tree guide, I learned that it is an eastern hop hornbeam.
Members of the birch and alder family, these trees are often call "ironwoods," due to their heavy and very hard wood. Though now cultivated for ornamental plantings, hop hornbeams were once used to produce tool handles, wooden spokes, fence posts and oxen yokes (hence the hornbeam title); the "hop" designation refers to the appearance of their clustered seed pods, which resemble the plant component used for beer production. Eastern hop hornbeams are widely distributed across southeastern Canada and the eastern half of the U.S. but are generally found alone or in small stands; in fact, they are relatively small (usually 30 feet) and grow in the understory or along woodland margins. Their seeds, blown about by the autumn wind, are eaten by quail, grouse and small mammals.
Eastern hop hornbeams are tolerant of dry soils and often grow in cool, shaded areas. Indeed, the tree's only close relative in North America is the Knowlton hop hornbeam, which is found in canyons of the Southwest.
Members of the birch and alder family, these trees are often call "ironwoods," due to their heavy and very hard wood. Though now cultivated for ornamental plantings, hop hornbeams were once used to produce tool handles, wooden spokes, fence posts and oxen yokes (hence the hornbeam title); the "hop" designation refers to the appearance of their clustered seed pods, which resemble the plant component used for beer production. Eastern hop hornbeams are widely distributed across southeastern Canada and the eastern half of the U.S. but are generally found alone or in small stands; in fact, they are relatively small (usually 30 feet) and grow in the understory or along woodland margins. Their seeds, blown about by the autumn wind, are eaten by quail, grouse and small mammals.
Eastern hop hornbeams are tolerant of dry soils and often grow in cool, shaded areas. Indeed, the tree's only close relative in North America is the Knowlton hop hornbeam, which is found in canyons of the Southwest.
Saturday, April 26, 2008
Edge of the West
Driving westward across the Great Plains of North America, one notices that the woodlands thin out, the greenery diminishes and the air loses its humidity. While there is a gradual transition from eastern to western ecosystems, with no definitive border, geographers and botanists often use the 100th Meridian as the dividing line. West of this longitude, which runs through or near Abilene, Texas, Dodge City, Kansas and Pierre, South Dakota, increasing distance from Gulf of Mexico moisture, rising surface elevation and the "rain shadow" of the Rocky Mountains all combine to produce a drier landscape.
In reality, the leading edge of "the west" is angled a bit from southwest to northeast. After all, the 100th Meridian approaches the Gulf of Mexico in south Texas and the eastern Dakotas, though east of that longitude, are far removed from Gulf moisture. A line from the Big Bend of Texas to the high plains escarpment of eastern North Dakota might be more accurate; this margin would cut through west-central Oklahoma and central Kansas, both of which have a relatively dry, western landscape.
On these western High Plains, trees are limited to stream beds (except where artificially watered), crop fields require significant irrigation and shortgrass prairie replaces the rich, tallgrass province of the eastern Plains. A change in fauna is also observed; Swainson's and ferruginous hawks, prairie falcons, pronghorns, swift fox, jackrabbits, prairie dogs, thirteen-lined ground squirrels, burrowing owls, long-billed curlews, lark buntings and longspurs are among the High Plains residents.
In reality, the leading edge of "the west" is angled a bit from southwest to northeast. After all, the 100th Meridian approaches the Gulf of Mexico in south Texas and the eastern Dakotas, though east of that longitude, are far removed from Gulf moisture. A line from the Big Bend of Texas to the high plains escarpment of eastern North Dakota might be more accurate; this margin would cut through west-central Oklahoma and central Kansas, both of which have a relatively dry, western landscape.
On these western High Plains, trees are limited to stream beds (except where artificially watered), crop fields require significant irrigation and shortgrass prairie replaces the rich, tallgrass province of the eastern Plains. A change in fauna is also observed; Swainson's and ferruginous hawks, prairie falcons, pronghorns, swift fox, jackrabbits, prairie dogs, thirteen-lined ground squirrels, burrowing owls, long-billed curlews, lark buntings and longspurs are among the High Plains residents.
Friday, April 25, 2008
Spring Valley
The Spring Valley Wildlife Area, southeast of Dayton, is one of my favorite birding destinations in Ohio. Spreading across the Little Miami floodplain, this 842-acre refuge, centered on a shallow lake, is a mix of wetlands, riparian woods, hillside forest and upland meadows. Access to the refuge is via Roxanna-New Burlington Rd., which leads east from U.S. 42, approximately 6 miles north of Waynesville.
By late April, Spring Valley is teeming with summer residents and migrants. The lake attracts Canada geese, mallards, blue-winged teal, coot, wood ducks, pied-billed grebes and migrant ospreys. An excellent variety of herons, egrets and rails stalk the wetlands while killdeer, spotted sandpipers and migrant shorebirds scour the mudflats. Wetland songbirds, including eastern kingbirds, eastern phoebes, red-headed woodpeckers, common yellowthroats, tree swallows and prothonotary warblers, are abundant in the riparian woodlands.
The upland woods and meadows also attract a wide variety of birds. Barred owls, northern orioles, indigo buntings, barn swallows, wood thrushes, yellow warblers, American goldfinches, eastern bluebirds, yellow-breasted chats and white-eyed vireos are among the summer residents, joined by a mix of migrant songbirds in April and May. Mammals at Spring Valley include white-tailed deer, red fox, beaver, muskrat, mink and long-tailed weasels; of course, like most wetlands, the refuge is home to a wide variety of reptiles and amphibians, including the massasauga rattlesnake.
By late April, Spring Valley is teeming with summer residents and migrants. The lake attracts Canada geese, mallards, blue-winged teal, coot, wood ducks, pied-billed grebes and migrant ospreys. An excellent variety of herons, egrets and rails stalk the wetlands while killdeer, spotted sandpipers and migrant shorebirds scour the mudflats. Wetland songbirds, including eastern kingbirds, eastern phoebes, red-headed woodpeckers, common yellowthroats, tree swallows and prothonotary warblers, are abundant in the riparian woodlands.
The upland woods and meadows also attract a wide variety of birds. Barred owls, northern orioles, indigo buntings, barn swallows, wood thrushes, yellow warblers, American goldfinches, eastern bluebirds, yellow-breasted chats and white-eyed vireos are among the summer residents, joined by a mix of migrant songbirds in April and May. Mammals at Spring Valley include white-tailed deer, red fox, beaver, muskrat, mink and long-tailed weasels; of course, like most wetlands, the refuge is home to a wide variety of reptiles and amphibians, including the massasauga rattlesnake.
Thursday, April 24, 2008
Four Books
Over the past 50 years, I have read hundreds of books that have inspired and sustained my interest in the natural sciences. But, looking back, there are four that were especially influential in my development as a naturalist.
When I was ten or eleven, I read Twenty-thousand Leagues Under the Sea, by Jules Verne, probably the first novel that I ever completed. Written ninety years before I read it, the book instilled a passion for adventure in my soul, a gift that has taken me to many interesting places. Fifteen years later, my mother-in-law introduced me to the writings of Edwin Way Teale and I borrowed North with the Spring from her book shelf. Released in 1951 (the year after my birth), the book taught me that there was much to explore and learn about close to home; Teale was fascinated by everything in nature and his enthusiasm was (and still is) contagious.
At the ripe old age of thirty, I read Edward Abbey's most famous tome, Desert Solitaire. Written in 1968, it recounts a year that he served as a ranger at Arches National Park, in Utah. His irascible style, combining a passion for wilderness with a justifiable distrust of Federal conservation programs, infused a healthy amount of scepticism into my view of man's effort to govern this planet. Finally, River out of Eden, by Richard Dawkins, a British evolutionary biologist with a flare for controversy, taught me to look at natural science with a critical eye and to be intellectually honest when assessing man's traditional view of life, evolution and our place in the Universe.
When I was ten or eleven, I read Twenty-thousand Leagues Under the Sea, by Jules Verne, probably the first novel that I ever completed. Written ninety years before I read it, the book instilled a passion for adventure in my soul, a gift that has taken me to many interesting places. Fifteen years later, my mother-in-law introduced me to the writings of Edwin Way Teale and I borrowed North with the Spring from her book shelf. Released in 1951 (the year after my birth), the book taught me that there was much to explore and learn about close to home; Teale was fascinated by everything in nature and his enthusiasm was (and still is) contagious.
At the ripe old age of thirty, I read Edward Abbey's most famous tome, Desert Solitaire. Written in 1968, it recounts a year that he served as a ranger at Arches National Park, in Utah. His irascible style, combining a passion for wilderness with a justifiable distrust of Federal conservation programs, infused a healthy amount of scepticism into my view of man's effort to govern this planet. Finally, River out of Eden, by Richard Dawkins, a British evolutionary biologist with a flare for controversy, taught me to look at natural science with a critical eye and to be intellectually honest when assessing man's traditional view of life, evolution and our place in the Universe.
Wednesday, April 23, 2008
Leaving the Den
Looking for early warblers several days ago, I noticed movement in our neighbor's large walnut tree; this turned out to be an eastern gray squirrel attempting to nudge her youngsters from the nest cavity. On the first evening, one of the toddlers did emerge onto the adjacent limb, making short excursions and then returning to the den for reassurance. By the second evening, three of the litter mates were scampering twenty feet or more from the cavity and, by last evening, the fourth and final sibling had joined them. Once she had them entertained, the exhausted mother would find a limb beyond their immediate range and sprawl out to get some rest.
After a gestation period of six weeks, these young squirrels were likely born in early March and will not be fully weaned for another three weeks. By mid summer, their mother will breed once again, giving birth to a second litter in mid-late August. The current litter mates will be independent by that time and, like the adults, will consume a mixed diet of insects, bird eggs, mushrooms, berries, bulbs and a variety of nuts, storing some of the larder and remaining active through the winter.
Enjoying their first spring, these young squirrels will have an average life span of six years. Disease, predation (hawks, owls, fox, raccoons, cats, snakes), human hunting and automobiles are the primary causes of death.
After a gestation period of six weeks, these young squirrels were likely born in early March and will not be fully weaned for another three weeks. By mid summer, their mother will breed once again, giving birth to a second litter in mid-late August. The current litter mates will be independent by that time and, like the adults, will consume a mixed diet of insects, bird eggs, mushrooms, berries, bulbs and a variety of nuts, storing some of the larder and remaining active through the winter.
Enjoying their first spring, these young squirrels will have an average life span of six years. Disease, predation (hawks, owls, fox, raccoons, cats, snakes), human hunting and automobiles are the primary causes of death.
Tuesday, April 22, 2008
Earth Day
I applaud those who established the original Earth Day, in 1970, and those who organize and promote its annual commemoration. Today, we stop to marvel at the beauty and diversity of our planet, acknowledge the many ways in which we impact our natural world and investigate how we, collectively and individually, can reduce that impact.
Unfortunately, like half-hearted Christians who limit their church attendance to Christmas and Easter, many who gather for the Earth Day celebrations are there to enjoy the music, eat the organic foods and walk away with free saplings. They hear the message, voice their support and then return to their usual lifestyle, which often includes excessive consumption of fossil fuels, the use of herbicides and pesticides, a limited effort at recycling and little support for conservation organizations.
Americans love their holidays and retailers love them more. Even Earth Day, with its vital message of hope for our planet, has become just another heavily-marketed opportunity for consumerism.
Unfortunately, like half-hearted Christians who limit their church attendance to Christmas and Easter, many who gather for the Earth Day celebrations are there to enjoy the music, eat the organic foods and walk away with free saplings. They hear the message, voice their support and then return to their usual lifestyle, which often includes excessive consumption of fossil fuels, the use of herbicides and pesticides, a limited effort at recycling and little support for conservation organizations.
Americans love their holidays and retailers love them more. Even Earth Day, with its vital message of hope for our planet, has become just another heavily-marketed opportunity for consumerism.
Monday, April 21, 2008
Birding Season
Bird watching is a popular, year-round activity and there are certainly birding highlights for any month of the year. But, for avid birders, the span from mid April to mid May is their peak season.
In mid April, some winter birds have not yet departed for the north and many of the summer birds are beginning to arrive. By late in the month, the tide of migrants (shorebirds, warblers) is beginning to peak and most of the summer residents, including hummingbirds, have returned. Indeed, through much of the U.S., the last week in April and first week in May offer a better opportunity to see the most species in one day than any other time of the year.
As experienced birders know, early morning and the late daylight hours are the best times to observe these residents and migrants. Visiting a variety of habitats (wetlands, grasslands and woodlands) will, of course, increase the number of species that you find. In the Midwest, even novice birders should be able to identify fifty or more species in the course of a mid spring day.
In mid April, some winter birds have not yet departed for the north and many of the summer birds are beginning to arrive. By late in the month, the tide of migrants (shorebirds, warblers) is beginning to peak and most of the summer residents, including hummingbirds, have returned. Indeed, through much of the U.S., the last week in April and first week in May offer a better opportunity to see the most species in one day than any other time of the year.
As experienced birders know, early morning and the late daylight hours are the best times to observe these residents and migrants. Visiting a variety of habitats (wetlands, grasslands and woodlands) will, of course, increase the number of species that you find. In the Midwest, even novice birders should be able to identify fifty or more species in the course of a mid spring day.
Sunday, April 20, 2008
A Jolt of Reality
This week's earthquake and aftershocks in the Midwest were an unexpected reminder that we are all subject to natural catastrophes, no matter the location of our home. While hurricanes lash the Southeast, volcanoes threaten the Pacific Northwest and earthquakes continually rearrange California, those of us in the Heartland focus our concerns on tornadoes, hail storms and blizzards. The potential for an earthquake is generally far from our mind.
Geologists tell us that this recent quake, centered in southeast Illinois, originated along the Wabash Valley fault system, a branch of the New Madrid fault that altered the course of the Mississippi River in 1811-1812. This fault network lies deep in the Precambrian basement rock, the remnants of an aborted Continental rift that developed 600 million years ago; since the fault has since been covered by a thick layer of Paleozoic sediments, the earthquake was relatively mild at the surface, causing a minimal amount of destruction and no human deaths.
Nevertheless, it is a reminder that Earth's tectonic plates continue to shift, collide and otherwise interact. These processes lead to increasing pressure within the plates, which is released at sites of weakness (including old rift zones or suture lines); since these features are not completely mapped and understood, we are all at potential risk for earthquakes, though some of us much more than others. In other words, destructive quakes are not limited to the plate margins and are certainly not restricted to the impoverished, developing countries of this planet!
Geologists tell us that this recent quake, centered in southeast Illinois, originated along the Wabash Valley fault system, a branch of the New Madrid fault that altered the course of the Mississippi River in 1811-1812. This fault network lies deep in the Precambrian basement rock, the remnants of an aborted Continental rift that developed 600 million years ago; since the fault has since been covered by a thick layer of Paleozoic sediments, the earthquake was relatively mild at the surface, causing a minimal amount of destruction and no human deaths.
Nevertheless, it is a reminder that Earth's tectonic plates continue to shift, collide and otherwise interact. These processes lead to increasing pressure within the plates, which is released at sites of weakness (including old rift zones or suture lines); since these features are not completely mapped and understood, we are all at potential risk for earthquakes, though some of us much more than others. In other words, destructive quakes are not limited to the plate margins and are certainly not restricted to the impoverished, developing countries of this planet!
The Coastal Plain
About ten miles south of Cape Girardeau, Missouri, I-55 leaves the stream-carved, rocky terrain of the Ozark Highlands and drops onto the flat landscape of the Coastal Plain. Created by intermittent incursions of Cenozoic seas, this Plain runs along the Atlantic Coast from southern New England to Florida and along the Gulf Coast from Florida to Mexico. In the south-central U.S., this geophysical province extends northward to the junction of the Ohio and Mississippi Rivers, covering the Missouri Boot Heel, the southeastern half of Arkansas, most of Mississippi and all of Louisiana; this northward extension corresponds to rifting of that region as the Gulf of Mexico opened.
The inland border of the Coastal Plain is not always as conspicuous as it is in southern Missouri. Through most of the Mid-Atlantic and Southeastern region, the Plain blends with the rolling terrain of the Piedmont, which stretches between the Appalachian Mountains and the Coastal Plain. The seaward edge of the Piedmont (and thus its transition to the Coastal Plain) is evident along the major rivers, which form waterfalls at this boundary (known to geologists as the "fall line"). As the rivers flow eastward toward the ocean, they cross the hard, Precambrian bedrock of the Piedmont and enter the soft, poorly compacted and more easily eroded deposits of the Coastal Plain, producing waterfalls at the transition zone. Many of the eastern cities, including Wilmington, Philadelphia, Baltimore, Washington, Richmond, Raleigh and Macon are located along this fall line.
Before humans arrived, the Coastal Plain was covered with vast wetlands, pine woodlands and tracts of swamp forest. Timber production, drainage for agriculture and other "development" has converted most of the Province to crop fields, towns, beach resorts and industrial cities. Few remnants of the original wetlands survive, protected within State and Federal Preserves; even these are threatened by pollution and water diversion.
The inland border of the Coastal Plain is not always as conspicuous as it is in southern Missouri. Through most of the Mid-Atlantic and Southeastern region, the Plain blends with the rolling terrain of the Piedmont, which stretches between the Appalachian Mountains and the Coastal Plain. The seaward edge of the Piedmont (and thus its transition to the Coastal Plain) is evident along the major rivers, which form waterfalls at this boundary (known to geologists as the "fall line"). As the rivers flow eastward toward the ocean, they cross the hard, Precambrian bedrock of the Piedmont and enter the soft, poorly compacted and more easily eroded deposits of the Coastal Plain, producing waterfalls at the transition zone. Many of the eastern cities, including Wilmington, Philadelphia, Baltimore, Washington, Richmond, Raleigh and Macon are located along this fall line.
Before humans arrived, the Coastal Plain was covered with vast wetlands, pine woodlands and tracts of swamp forest. Timber production, drainage for agriculture and other "development" has converted most of the Province to crop fields, towns, beach resorts and industrial cities. Few remnants of the original wetlands survive, protected within State and Federal Preserves; even these are threatened by pollution and water diversion.
Thursday, April 17, 2008
The Eastern Thrasher
A brown thrasher turned up in our yard this week, the first I've seen this spring. Breeding across southern Canada and the U.S., east of the Rockies, this bird summers in the southeastern and south-central States, including southern Missouri; on occasion, I have seen them in central Missouri during mild winters.
Jay sized, the brown thrasher is identified by his red-brown plumage, yellow eye, long tail and heavily streaked breast; his long, thin bill is slightly curved, but not to the degree of his southwestern cousins. Usually seen alone or in pairs, this bird prefers thickets and wood margins where he searches for insects in the leaf litter and sometimes feeds on berries. A bulky nest of twigs and plant debris is generally built in shrubs or directly on the ground.
Thrashers are in the same family as catbirds and mockingbirds and their song is similar, a varied repetition of short "phrases;" in the brown thrasher's case, each phrase is repeated twice. It is this tune, delivered from a conspicuous perch, that often draws our attention to an otherwise retiring summer resident.
Jay sized, the brown thrasher is identified by his red-brown plumage, yellow eye, long tail and heavily streaked breast; his long, thin bill is slightly curved, but not to the degree of his southwestern cousins. Usually seen alone or in pairs, this bird prefers thickets and wood margins where he searches for insects in the leaf litter and sometimes feeds on berries. A bulky nest of twigs and plant debris is generally built in shrubs or directly on the ground.
Thrashers are in the same family as catbirds and mockingbirds and their song is similar, a varied repetition of short "phrases;" in the brown thrasher's case, each phrase is repeated twice. It is this tune, delivered from a conspicuous perch, that often draws our attention to an otherwise retiring summer resident.
Wednesday, April 16, 2008
April at Eagle Bluffs
Back in Missouri, I decided to visit the Eagle Bluffs Conservation Area, southwest of Columbia, this morning. Purple henbit blazed on the open fields and kestrels clung to the wires, trying to balance in the gusty south wind. Out on the lakes, coot and blue-winged teal were the dominant waterfowl though northern shovelers were also common. Double-crested cormorants lounged in the dead trees and several large flocks of American white pelicans rested on sandbars and mudflats. Overhead, groups of turkey vultures soared in the morning breeze and a single bald eagle flapped above the wetlands, spooking the teal into frenzied flight.
While killdeer and a few spotted sandpipers fed along the shorelines, the variety of shorebirds was rather lackluster this morning. Likewise, the bottomland woods were still winter-like, no doubt subdued from the recent cold spell. And though woodpeckers, chickadees and white-throated sparrows called from the woodland, only the insistent chatter of a house wren foretold the onset of a new season.
By mid morning, the pelicans began to depart, the flocks rising in sequence, circling over the refuge and then drifting northward up the Missouri River Valley. Within a few more weeks, most of the migrants will have passed through the refuge and Eagle Bluffs will settle into its rich, verdant season.
While killdeer and a few spotted sandpipers fed along the shorelines, the variety of shorebirds was rather lackluster this morning. Likewise, the bottomland woods were still winter-like, no doubt subdued from the recent cold spell. And though woodpeckers, chickadees and white-throated sparrows called from the woodland, only the insistent chatter of a house wren foretold the onset of a new season.
By mid morning, the pelicans began to depart, the flocks rising in sequence, circling over the refuge and then drifting northward up the Missouri River Valley. Within a few more weeks, most of the migrants will have passed through the refuge and Eagle Bluffs will settle into its rich, verdant season.
Cheyenne Bottoms
Internationally famous as a key staging area for migrant waterfowl and shorebirds, the vast wetlands of Cheyenne Bottoms, north of Great Bend, Kansas, also attract flocks of naturalists in the spring and fall; late April through mid May is arguably the best time to visit. Most of the wetland complex is managed by the Kansas Department of Wildlife & Parks, which uses levees and pumps to control water levels in the broad, shallow pools; this portion is accessed by a levee road that runs between U.S. 281 and Kansas Route 156. The Nature Conservancy owns 7300 acres at the northwest corner of the complex, reached by roadways off U.S. 281 or Kansas Route 4, south or east of Hoisington, respectively.
Views from the Kansas DWP levee road are extensive and, while many birds will be seen in the shallows close to the roadway, use of a spotting scope is recommended. Closer viewing is obtained from a rest stop along Kansas 156 or via the roadways of the Nature Conservancy's Preserve, mentioned above. Highlights of my visit included huge flocks of American white pelicans, a large number of avocets, several flocks of white-faced ibis and an unbelievably large concentration of American coots; feeding on the primary levee or in the adjacent waters, huge numbers would scurry off as my truck approached.
Views from the Kansas DWP levee road are extensive and, while many birds will be seen in the shallows close to the roadway, use of a spotting scope is recommended. Closer viewing is obtained from a rest stop along Kansas 156 or via the roadways of the Nature Conservancy's Preserve, mentioned above. Highlights of my visit included huge flocks of American white pelicans, a large number of avocets, several flocks of white-faced ibis and an unbelievably large concentration of American coots; feeding on the primary levee or in the adjacent waters, huge numbers would scurry off as my truck approached.
Tuesday, April 15, 2008
Quivira
Named for Native Americans that once inhabited the region, Quivira National Wildlife Refuge covers almost 22,000 acres in the Arkansas Valley of south-central Kansas. Its vast and varied wetlands attract huge flocks of waterfowl, cranes, pelicans and other water birds during the spring and fall migrations. The refuge lies southeast of Great Bend, midway between U.S. 281 and Kansas Highway 14.
Mild, sunny weather made my visit especially pleasant yesterday morning. Dozens of white-tailed deer browsed on the meadows and ring-necked pheasants foraged along the dirt-gravel roadways. Heading for the Big Salt Marsh area, I saw several red-tailed hawks perched in the cottonwoods and watched flocks of Franklin's gulls cavort above the fields. Blue-winged teal, coot and northern shovelers gathered in the sloughs and pools while a variety of shorebirds, including greater and lesser yellowlegs, American avocets, black-necked stilts, semipalmated sandpipers, snowy plovers and long-billed dowitchers patrolled the shallows and mudflats.
Several large flocks of American white pelicans rested along the lakes where cormorants, ruddy ducks, eared grebes and pied-billed grebes fed on the open waters. By mid morning, other pelicans passed overhead, moving north in large, wavering V's; their movement enticed the resting flocks into the air and I was treated to an awe-inspiring spectacle of a thousand or more of these majestic birds in flight. Black-crowned night herons, white-faced ibis, great blue herons and a lone American bittern rounded out a memorable morning at this fabulous refuge.
Visitors arriving later in the spring have the opportunity to see many other birds that breed at Quivira. Among the notables are Mississippi kites, least bitterns, black rails, upland sandpipers, least and black terns, burrowing owls, scissor-tailed flycatchers, bobolinks and blue grosbeaks.
Mild, sunny weather made my visit especially pleasant yesterday morning. Dozens of white-tailed deer browsed on the meadows and ring-necked pheasants foraged along the dirt-gravel roadways. Heading for the Big Salt Marsh area, I saw several red-tailed hawks perched in the cottonwoods and watched flocks of Franklin's gulls cavort above the fields. Blue-winged teal, coot and northern shovelers gathered in the sloughs and pools while a variety of shorebirds, including greater and lesser yellowlegs, American avocets, black-necked stilts, semipalmated sandpipers, snowy plovers and long-billed dowitchers patrolled the shallows and mudflats.
Several large flocks of American white pelicans rested along the lakes where cormorants, ruddy ducks, eared grebes and pied-billed grebes fed on the open waters. By mid morning, other pelicans passed overhead, moving north in large, wavering V's; their movement enticed the resting flocks into the air and I was treated to an awe-inspiring spectacle of a thousand or more of these majestic birds in flight. Black-crowned night herons, white-faced ibis, great blue herons and a lone American bittern rounded out a memorable morning at this fabulous refuge.
Visitors arriving later in the spring have the opportunity to see many other birds that breed at Quivira. Among the notables are Mississippi kites, least bitterns, black rails, upland sandpipers, least and black terns, burrowing owls, scissor-tailed flycatchers, bobolinks and blue grosbeaks.
The Flint Hills
Americans who have never been to Kansas probably envision the State to be a flat plain covered with wheat and sunflower fields. But then, they've never seen the Flint Hills.
A broad uplift of Permian sediments, stretching from Manhattan to Wichita, the Flint Hills have been carved into a landscape of ridges and valleys by numerous tributaries of the Kansas and Arkansas Rivers. The thin, rocky soil of the ridges, covered by tallgrass prairie following the Pleistocene Ice Age, was never amenable to farming; once grazed by huge herds of bison, these grasslands are now used for cattle ranching. Some crop production does occur in the wooded valleys, where the soil is thicker, richer and able to retain moisture. A wide variety of grassland birds and mammals inhabit the Flint Hills and prairie wildflowers adorn the slopes. Those interested in learning more about the natural and human history of the area are encour-aged to visit the Tallgrass Prairie National Preserve, 16 miles west of Emporia (north of U.S. 50 on Kansas 177).
While I-70 slices through the Flint Hills and offers a scenic cross-section (between Topeka and Junction City), the landscape, flora and fauna are best viewed by travelling along Kansas 177, from Manhattan, on the north end, to El Dorado, northeast of Wichita; as noted above, the Tallgrass Prairie National Preserve is on this route. Visitors in April will likely experience hazy skies and charred hillsides, the effects of seasonal burning to clear the grasslands of invasive plants and trees. By later in the month, new grass will be sprouting and summer birds, including western kingbirds, blue grosbeaks, upland sandpipers and scissor-tailed flycatchers, will return to nest.
A broad uplift of Permian sediments, stretching from Manhattan to Wichita, the Flint Hills have been carved into a landscape of ridges and valleys by numerous tributaries of the Kansas and Arkansas Rivers. The thin, rocky soil of the ridges, covered by tallgrass prairie following the Pleistocene Ice Age, was never amenable to farming; once grazed by huge herds of bison, these grasslands are now used for cattle ranching. Some crop production does occur in the wooded valleys, where the soil is thicker, richer and able to retain moisture. A wide variety of grassland birds and mammals inhabit the Flint Hills and prairie wildflowers adorn the slopes. Those interested in learning more about the natural and human history of the area are encour-aged to visit the Tallgrass Prairie National Preserve, 16 miles west of Emporia (north of U.S. 50 on Kansas 177).
While I-70 slices through the Flint Hills and offers a scenic cross-section (between Topeka and Junction City), the landscape, flora and fauna are best viewed by travelling along Kansas 177, from Manhattan, on the north end, to El Dorado, northeast of Wichita; as noted above, the Tallgrass Prairie National Preserve is on this route. Visitors in April will likely experience hazy skies and charred hillsides, the effects of seasonal burning to clear the grasslands of invasive plants and trees. By later in the month, new grass will be sprouting and summer birds, including western kingbirds, blue grosbeaks, upland sandpipers and scissor-tailed flycatchers, will return to nest.
Road Trip
My high school history teacher and swimming coach was a bachelor who loved to take weekend excursions. On Friday evening or Saturday morning, he would depart Cincinnati, driving as far as he could over the first day and returning on the second; generally, he would have no specific destination in mind but varied his direction to ensure exposure to a wide variety of places. Though we often kidded him about this unusual "hobby," I secretly envied his freedom and admired his adventurous spirit.
Fueled by the nature travel writings of Edwin Way Teale in my late twenties, I adopted my teacher's pattern of taking short trips to places unknown. Since my wife also enjoyed these drives (and my kids learned to tolerate them), they became a family tradition over the years, though their frequency dropped off as our children aged and other responsibilities intervened. Now that we are on our own once again, my wife and I (mostly me) have resumed these adventures; over the past few days, I made a loop through Kansas, a great destination for any naturalist.
Fueled by the nature travel writings of Edwin Way Teale in my late twenties, I adopted my teacher's pattern of taking short trips to places unknown. Since my wife also enjoyed these drives (and my kids learned to tolerate them), they became a family tradition over the years, though their frequency dropped off as our children aged and other responsibilities intervened. Now that we are on our own once again, my wife and I (mostly me) have resumed these adventures; over the past few days, I made a loop through Kansas, a great destination for any naturalist.
Saturday, April 12, 2008
April Chill
The latest spring storm, now centered over Lake Michigan, is bringing cold, gray windy weather to the Midwest. Its massive windfield, rotating counterclockwise, extends across southern Canada, southward over the eastern Plains, eastward across the mid Mississippi Valley and northeastward over the Ohio Valley and Appalachian Plateau. It is certainly dousing our spring fever!
Such late, winter-like outbreaks are not uncommon in the Midwest and the comfort of persistent, mild weather is not assured until May. But this latest storm system has been especially powerful, raking the country with high winds from the Rockies to the Appalachians. Its leading edge produced severe thunderstorms and tornadoes from Texas to Tennessee and its massive swirl has transported a prodigious amount of moisture from the Gulf of Mexico to the American Heartland.
It is a raw, overcast day in central Missouri as we remain within the grip of this super-sized storm. Northwest winds, spitting intermittent drizzle, are keeping the windchill in the lower 30s and dashing our thoughts of spring. But the system keeps inching toward the northeast and the sun and warmth will gradually return over the next few days. Within a few weeks, we'll be complaining about the heat!
Such late, winter-like outbreaks are not uncommon in the Midwest and the comfort of persistent, mild weather is not assured until May. But this latest storm system has been especially powerful, raking the country with high winds from the Rockies to the Appalachians. Its leading edge produced severe thunderstorms and tornadoes from Texas to Tennessee and its massive swirl has transported a prodigious amount of moisture from the Gulf of Mexico to the American Heartland.
It is a raw, overcast day in central Missouri as we remain within the grip of this super-sized storm. Northwest winds, spitting intermittent drizzle, are keeping the windchill in the lower 30s and dashing our thoughts of spring. But the system keeps inching toward the northeast and the sun and warmth will gradually return over the next few days. Within a few weeks, we'll be complaining about the heat!
Friday, April 11, 2008
Boulder Mountain Parks
Adorned by the famous Flatirons, giant slabs of Pennsylvanian sandstone, the foothills west of Boulder, Colorado, offer some of the best hiking along the Front Range. Boulder Mountain Parks, just west and southwest of the city, is an excellent area to explore the varied habitats of the foothills zone.
Start at the west end of Baseline Road, in southwest Boulder, and follow the Gregory Canyon Trail as it climbs through a scenic cleft in the foothills. Leveling out atop the ridge and angling to the south, pick up the Ranger Trail, which continues southward and intersects the Green Mountain Trail. Turn left and ascend to the summit of Green Mountain, 8144 feet, which provides a scenic panorama of the Front Range. When heading back to Boulder, take the Saddle Rock Trail, winding among the massive Flatirons.
Ponderosa parklands, Douglas fir forest and foothill meadows are the primary habitats in the Park, attracting a wide variety of wildlife. Visitors in late April should see rock and canyon wrens, western and mountain bluebirds, Townsend's solitaires, Williamson's sapsuckers, violet-green swallows, Steller's jays, pygmy nuthatches and mountain chickadees; broad-tailed hummingbirds arrive by May. Raptors include golden eagles, Cooper's hawks, red-tailed hawks and the occasional northern saw-whet owl. Mule deer are abundant here, attracting mountain lions to the area; black bear, Abert's squirrels, golden-mantled ground squirrels and Colorado chipmunks also inhabit the Park.
Start at the west end of Baseline Road, in southwest Boulder, and follow the Gregory Canyon Trail as it climbs through a scenic cleft in the foothills. Leveling out atop the ridge and angling to the south, pick up the Ranger Trail, which continues southward and intersects the Green Mountain Trail. Turn left and ascend to the summit of Green Mountain, 8144 feet, which provides a scenic panorama of the Front Range. When heading back to Boulder, take the Saddle Rock Trail, winding among the massive Flatirons.
Ponderosa parklands, Douglas fir forest and foothill meadows are the primary habitats in the Park, attracting a wide variety of wildlife. Visitors in late April should see rock and canyon wrens, western and mountain bluebirds, Townsend's solitaires, Williamson's sapsuckers, violet-green swallows, Steller's jays, pygmy nuthatches and mountain chickadees; broad-tailed hummingbirds arrive by May. Raptors include golden eagles, Cooper's hawks, red-tailed hawks and the occasional northern saw-whet owl. Mule deer are abundant here, attracting mountain lions to the area; black bear, Abert's squirrels, golden-mantled ground squirrels and Colorado chipmunks also inhabit the Park.
Thursday, April 10, 2008
Chaos in the Heartland
This morning, a massive spring storm, centered over southwest Kansas, is producing severe weather and travel problems across the Heartland. Like a giant pinwheel, the storm is pulling in moisture from the Gulf of Mexico and dropping heavy rain on the south-central States. Along its northern edge, this moisture is entering cooler air and, as it is swept westward, is bringing "upslope" snow to the Front Range of Colorado and Wyoming.
On the south side of the storm, the collision of dry, cooler air from the west with warm, moist air from the southeast, has been igniting powerful thunderstorms since yesterday afternoon. The intersection of the westerly jet stream, southerly flow ahead of the front and easterly winds from the preceding system is triggering rotation in these storms, resulting in numerous tornadoes across the Southern Plains and lower Mississippi Valley.
Here in central Missouri, east winds from the last front are keeping the air cool and stable, preventing the development of severe weather. Heavy rains are forecast but, unless the storm pulls warm, unstable air into our region (as it moves to the northeast), the severe thunderstorms and tornadoes should stay to our south and east.
On the south side of the storm, the collision of dry, cooler air from the west with warm, moist air from the southeast, has been igniting powerful thunderstorms since yesterday afternoon. The intersection of the westerly jet stream, southerly flow ahead of the front and easterly winds from the preceding system is triggering rotation in these storms, resulting in numerous tornadoes across the Southern Plains and lower Mississippi Valley.
Here in central Missouri, east winds from the last front are keeping the air cool and stable, preventing the development of severe weather. Heavy rains are forecast but, unless the storm pulls warm, unstable air into our region (as it moves to the northeast), the severe thunderstorms and tornadoes should stay to our south and east.
Wednesday, April 9, 2008
The Mars Controversy
Man has always been a curious creature, eager to explore new areas. After all, this trait took him across the globe and to the moon. Yet, NASA's current plan to send astronauts to Mars has met with a good deal of controversy. Opponents say that the money would be better spent improving conditions on Earth or that, until our space travel technology is significantly more advanced, it is more efficient, less costly and much safer to explore the cosmos with robotic probes.
While I tend to agree with these latter arguments, I am more disturbed by the rationale for the project, expressed by various scientists. First, they say, we must go there to find out whether life exists beyond our planet. But whether or not there is or was life elsewhere in our solar system, there is a mathematical certainty that it exists in other star systems and galaxies. Secondly, some argue that the human race needs a planet to escape to when we exhaust or destroy the resources on Earth. This argument is both pessimistic and ridiculous, suggesting that we have the capability to colonize Mars but not the intelligence or technology to protect and preserve our home planet.
John Kennedy's challenge to put men on the moon, expressed in the heat of the Cold War, was more political than scientific. And Bush's exhortation to send man to Mars is an effort to restore his own image in the history books after he has wreaked havoc on Earth.
While I tend to agree with these latter arguments, I am more disturbed by the rationale for the project, expressed by various scientists. First, they say, we must go there to find out whether life exists beyond our planet. But whether or not there is or was life elsewhere in our solar system, there is a mathematical certainty that it exists in other star systems and galaxies. Secondly, some argue that the human race needs a planet to escape to when we exhaust or destroy the resources on Earth. This argument is both pessimistic and ridiculous, suggesting that we have the capability to colonize Mars but not the intelligence or technology to protect and preserve our home planet.
John Kennedy's challenge to put men on the moon, expressed in the heat of the Cold War, was more political than scientific. And Bush's exhortation to send man to Mars is an effort to restore his own image in the history books after he has wreaked havoc on Earth.
Tuesday, April 8, 2008
The Chemicals of Spring
Ah, spring! The flowers, the birds, the balmy weather and a vast array of herbicides and pesticides coating American lawns. It is the season of lawn care commercials, picturing happy families and their pets on bright green, weedless, grub-free yards. Jealous neighbors, with pock-marked lots, just stare and shake their heads. One call to the Lawn Wizard, with his tank truck of chemicals, would solve their problem.
Americans, devoted to their patch of grass, have been taught that dandelions and other broad-leafed "weeds" are a scourge on society and that we owe it to our neighbors to maintain a "healthy," attractive lawn. And the only way to achieve these goals is to spread a mixture of poisons on our grass or, better yet, hire a company to do it for you!
While all of the attention seems to be on global warming these days, we overlook the huge quantity of toxins that are poured onto lawns and crop fields, eventually making their way into our rivers and wetlands. I recommend that we let the cottontails consume our dandelions, plantain and clover and rely on the birds and moles to control the grubs. Our neighbors will get over it and we'll all be better off!
Americans, devoted to their patch of grass, have been taught that dandelions and other broad-leafed "weeds" are a scourge on society and that we owe it to our neighbors to maintain a "healthy," attractive lawn. And the only way to achieve these goals is to spread a mixture of poisons on our grass or, better yet, hire a company to do it for you!
While all of the attention seems to be on global warming these days, we overlook the huge quantity of toxins that are poured onto lawns and crop fields, eventually making their way into our rivers and wetlands. I recommend that we let the cottontails consume our dandelions, plantain and clover and rely on the birds and moles to control the grubs. Our neighbors will get over it and we'll all be better off!
Monday, April 7, 2008
Pied-billed Grebes
While almost never found in large flocks, the pied-billed grebe is the most widespread grebe in North America. This small, stocky bird prefers marshy shallows where it dives for fish and aquatic invertebrates. Easily identified by its short, blunt bill which is marked with a black ring, this grebe is usually seen alone or in pairs; when disturbed, it dives underwater or sinks among the reeds and is rarely seen in flight.
In April, pied-billed grebes are common on Midwest lakes as their spring migration peaks; indeed, seasonal migrations are usually the only time that you will find them in scattered flocks. Breeding across southern Canada, the U.S. and Mexico, they winter on open waters throughout the southern half of the U.S. and Central America; though they prefer fresh water, some may be found on brackish bays during the colder months.
Like most grebes and loons, pied-bills nest on floating mats of vegetation, anchored among cattails or other aquatic plants. The chicks, which have striped plumage, may be seen riding on their parent's back by late spring.
In April, pied-billed grebes are common on Midwest lakes as their spring migration peaks; indeed, seasonal migrations are usually the only time that you will find them in scattered flocks. Breeding across southern Canada, the U.S. and Mexico, they winter on open waters throughout the southern half of the U.S. and Central America; though they prefer fresh water, some may be found on brackish bays during the colder months.
Like most grebes and loons, pied-bills nest on floating mats of vegetation, anchored among cattails or other aquatic plants. The chicks, which have striped plumage, may be seen riding on their parent's back by late spring.
Sunday, April 6, 2008
A Gang of Garters
Yesterday's warm, sunny afternoon seemed to be a good time to start the spring yard work. Near some old timbers on the south side of the house, my wife noticed a garter snake; within a few minutes, several more appeared, winding through the leaf litter and among the shrubs.
Garter snakes winter in groups of a hundred or more, usually choosing a cave or den with a south exposure. Come April, they begin to emerge on warm days, retreating to the den at night. Males are generally the first to wander from the winter retreat and are primarily concerned with locating females; early-mid spring is their mating season and they are more active and conspicuous now than they will be for the rest of the year. Yesterday's gang was in constant motion, scouring the area but showing no signs of hunting behavior.
Once the mating season is over, garter snakes become rather solitary and much less active. They are usually discovered while sunning themselves in mid morning and spend much of the day patiently stalking insects, worms, amphibians and small mammals. Fertilization is delayed and the female will give birth to anywhere from 10 to 60 live offspring in late summer; these young snakes are self sufficient from birth and will feast on worms and insects before the mass hibernation begins.
Garter snakes winter in groups of a hundred or more, usually choosing a cave or den with a south exposure. Come April, they begin to emerge on warm days, retreating to the den at night. Males are generally the first to wander from the winter retreat and are primarily concerned with locating females; early-mid spring is their mating season and they are more active and conspicuous now than they will be for the rest of the year. Yesterday's gang was in constant motion, scouring the area but showing no signs of hunting behavior.
Once the mating season is over, garter snakes become rather solitary and much less active. They are usually discovered while sunning themselves in mid morning and spend much of the day patiently stalking insects, worms, amphibians and small mammals. Fertilization is delayed and the female will give birth to anywhere from 10 to 60 live offspring in late summer; these young snakes are self sufficient from birth and will feast on worms and insects before the mass hibernation begins.
Saturday, April 5, 2008
The Baobab Spark
There are moments in our life when we suddenly see our world in a different light, when our perspective changes and our life takes a new course. In my life, one of these moments occurred during the third or fourth grade when, leafing through my first geography text, I came upon the photo of a giant baobab tree. An African family was living in its hollowed trunk and a caption related that this massive "tree of life" provided many of their needs, including food, water, shelter and materials for clothing and rope.
Having a rather sheltered view of the planet at that time, I was fascinated by the photo, the image of which remains clear in my mind almost fifty years later. At that moment, I was seeing a baobab tree for the first time but, more importantly, realized that there were many exotic species and places out there that I knew nothing about. Geography soon became my favorite subject and, over the years, spawned my interest in the varied disciplines of earth science.
Of course, some of us are more receptive to these moments, based on our genes, our experience and the influence of others. But, if we make the effort to look back, we can all remember people, places and events that had a profound impact on our lives. The baobab photo was certainly a spark for me.
Having a rather sheltered view of the planet at that time, I was fascinated by the photo, the image of which remains clear in my mind almost fifty years later. At that moment, I was seeing a baobab tree for the first time but, more importantly, realized that there were many exotic species and places out there that I knew nothing about. Geography soon became my favorite subject and, over the years, spawned my interest in the varied disciplines of earth science.
Of course, some of us are more receptive to these moments, based on our genes, our experience and the influence of others. But, if we make the effort to look back, we can all remember people, places and events that had a profound impact on our lives. The baobab photo was certainly a spark for me.
Friday, April 4, 2008
The Ringed Planet
Throughout April, Saturn, the sixth planet from our sun, will be high in the night sky. More than 9.5 times further from the sun than is Earth, the ringed planet takes 29.5 years to complete its orbit; on the other hand, Saturn has a rapid rotation, completing its day in 10.5 hours.
One of the gas planets (which also include Jupiter, Neptune and Uranus), Saturn has an equatorial diameter of 74.5 thousand miles, more than 9 times that of the Earth. It is composed primarily of hydrogen and helium, surrounding a core of molten rock; ammonia, methane, water and other compounds are found in lesser amounts. Storms and high winds characterize the atmosphere and, in 2006, the Cassini spacecraft documented the presence of a large, hexagon-shaped, hurricane-like storm over Saturn's south pole.
But Saturn is most famous for its rings, which are composed of ice, dust and rocky debris. While they have a diameter of 150,000 miles, the rings are less than 1 mile thick. Their changing appearance suggests to astronomers that they are relatively young (perhaps less than ten million years old) and that they may have originated from the collision of a comet with one of Saturn's moons. Not to worry: the planet still has sixty moons, half of which are named; Titan, its largest satellite, is the only moon in our solar system to have a significant atmosphere.
One of the gas planets (which also include Jupiter, Neptune and Uranus), Saturn has an equatorial diameter of 74.5 thousand miles, more than 9 times that of the Earth. It is composed primarily of hydrogen and helium, surrounding a core of molten rock; ammonia, methane, water and other compounds are found in lesser amounts. Storms and high winds characterize the atmosphere and, in 2006, the Cassini spacecraft documented the presence of a large, hexagon-shaped, hurricane-like storm over Saturn's south pole.
But Saturn is most famous for its rings, which are composed of ice, dust and rocky debris. While they have a diameter of 150,000 miles, the rings are less than 1 mile thick. Their changing appearance suggests to astronomers that they are relatively young (perhaps less than ten million years old) and that they may have originated from the collision of a comet with one of Saturn's moons. Not to worry: the planet still has sixty moons, half of which are named; Titan, its largest satellite, is the only moon in our solar system to have a significant atmosphere.
Thursday, April 3, 2008
The Pantanal
The Pantanal, thought to be the largest, undeveloped wetland complex on Earth, covers almost 70,000 square miles at the junction of Brazil, Bolivia and Paraguay. A desert landscape as recently as 13,000 years ago, this flat ecosystem is now a mosaic of meandering rivers, seasonal lakes, oxbows, sloughs, grasslands, marsh and woodlands. During the wet season, which lasts from October into April, 80% of the Pantanal (Portuguese for wetland) is flooded by its primary streams, which drain the adjacent highlands and distant mountains. With the onset of the dry season, the flora and fauna undergo a dramatic change, augmenting the tremendous array of life in the Pantanal.
Rivaling the diversity of the Amazon Rainforest, this wetland is home to over 700 species of birds, including greater rheas, toucans, macaws, parrots, giant black eagles and, of course, a wide variety of waders. Resident mammals include jaguars, ocelots, maned wolves, giant otters, Brazilian tapirs, howler and capuchin monkeys, giant anteaters and capybaras, the largest rodents on Earth. Anacondas and caimans are among the Pantanal's many reptiles and almost 300 species of fish inhabit its many lakes, streams and seasonal wetlands.
Though "undeveloped," the Pantanal has been used for cattle ranching and is threatened by a variety of human activities. Pollution from upstream mines, human settlements and agricultural areas is perhaps the major threat though deforestation, poaching and unregulated tourism all take a toll. Most recently, plans to divert water from this fragile ecosystem tempt disaster.
Rivaling the diversity of the Amazon Rainforest, this wetland is home to over 700 species of birds, including greater rheas, toucans, macaws, parrots, giant black eagles and, of course, a wide variety of waders. Resident mammals include jaguars, ocelots, maned wolves, giant otters, Brazilian tapirs, howler and capuchin monkeys, giant anteaters and capybaras, the largest rodents on Earth. Anacondas and caimans are among the Pantanal's many reptiles and almost 300 species of fish inhabit its many lakes, streams and seasonal wetlands.
Though "undeveloped," the Pantanal has been used for cattle ranching and is threatened by a variety of human activities. Pollution from upstream mines, human settlements and agricultural areas is perhaps the major threat though deforestation, poaching and unregulated tourism all take a toll. Most recently, plans to divert water from this fragile ecosystem tempt disaster.
Wednesday, April 2, 2008
Nature's Solar Panels
In the Temperate Zone of North America, April is the month of the leaf. From blades of grass to maple leaves to the giant leaves of the catalpa, nature unfurls her solar panels, converting solar energy to foodstuffs for all primary consumers. The latter include molds, fungi, bacteria, invertebrates and all herbivorous or omnivorous animals, including man. Since secondary consumers (also including man) feed on primary consumers, all terrestrial life is dependent on this annual emergence of leaves.
Despite the vital role that these photosynthetic structures play, nature lovers tend to dwell on flowers, birds and newborn mammals, the traditional symbols of spring. Yet, without leaves, these spring favorites could not exist. More than a conduit for energy trans-formation, leaves absorb carbon dioxide and release both oxygen and water vapor, playing an essential role in the maintenance of our atmosphere.
Beyond their value as producers of food and oxygen, leaves offer shade in the heat of summer, glorious color in the fall, protective cover during winter and vital nutrients for the spring growth of the next generation. More than any other structure in nature, the leaf epitomizes the annual cycle of life.
Despite the vital role that these photosynthetic structures play, nature lovers tend to dwell on flowers, birds and newborn mammals, the traditional symbols of spring. Yet, without leaves, these spring favorites could not exist. More than a conduit for energy trans-formation, leaves absorb carbon dioxide and release both oxygen and water vapor, playing an essential role in the maintenance of our atmosphere.
Beyond their value as producers of food and oxygen, leaves offer shade in the heat of summer, glorious color in the fall, protective cover during winter and vital nutrients for the spring growth of the next generation. More than any other structure in nature, the leaf epitomizes the annual cycle of life.
Tuesday, April 1, 2008
Thunderstorm Season
Thunderstorms feed on warm, moist, unstable air and are triggered by lift; the latter is provided by an upper level low or an approaching cold front. Such conditions begin to develop along the Gulf Coast States in February and the zone of thunderstorm frequency gradually shifts to the north and west over the ensuing months.
April marks the beginning of the severe thunderstorm season in the Midwest, which will continue through June. As the jet stream moves farther to the north, the Gulf of Mexico "opens up," allowing warm, moist air to invade the Heartland. This provides fuel for the thunderstorms which develop in advance of Pacific cold fronts. In this most common scenario, the storms cluster in swaths, oriented southwest to northeast, and move northeastward ahead of the front. This "training" produces recurrent, heavy rains along the swath, inducing floods; on the other hand, compacted storms tend to be less severe, since rain and "outflow" from the preceding storm cool the air and reduce instability.
The most severe thunderstorms, which often produce tornadoes, are generally isolated "supercells," which form along the "dry line;" this moving barrier separates the warm, humid air ahead of the storm from the cool, dry air behind the front. Energized by the jet stream, these monsters begin to rotate as the southeast flow in the "warm sector" collides with strong west winds at the dry line. Such conditions classically develop across "tornado alley," on the Great Plains, from mid spring through early summer.
April marks the beginning of the severe thunderstorm season in the Midwest, which will continue through June. As the jet stream moves farther to the north, the Gulf of Mexico "opens up," allowing warm, moist air to invade the Heartland. This provides fuel for the thunderstorms which develop in advance of Pacific cold fronts. In this most common scenario, the storms cluster in swaths, oriented southwest to northeast, and move northeastward ahead of the front. This "training" produces recurrent, heavy rains along the swath, inducing floods; on the other hand, compacted storms tend to be less severe, since rain and "outflow" from the preceding storm cool the air and reduce instability.
The most severe thunderstorms, which often produce tornadoes, are generally isolated "supercells," which form along the "dry line;" this moving barrier separates the warm, humid air ahead of the storm from the cool, dry air behind the front. Energized by the jet stream, these monsters begin to rotate as the southeast flow in the "warm sector" collides with strong west winds at the dry line. Such conditions classically develop across "tornado alley," on the Great Plains, from mid spring through early summer.
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