As the name implies, shorebirds spend at least part of their lives at the edge of some type of body of water. There are about 177 species worldwide, at least 47 of which live in the Western Hemisphere. These are broken into four "guilds": mud birds, wading birds, coastal birds, and upland birds. The complex and poorly understood migration of these travelers is forced, at least in part, by the need for a large food supply. They tend to fly towards the lengthening days, whether heading North or South. Many travel several hundred, to a few thousand miles on there journeys. A few, however, such as the hudsonian godwit and the red knot, travel up to 20,000 miles round-trip in one year! That is the equivalent of a trip 4/5ths of the way around the earth! The 10,000 mile one way journey takes them from the tip of South America, north to the Canadian arctic in a few weeks time.
As you might imagine, long migrations require consistent resting and feeding locations. For shorebirds, that generally means wetlands. Unfortunately humans have been destroying wetlands with reckless abandon for the past 100 years. It is only in the past couple of decades that realization of the impact this destruction has on a wide range of flora and fauna, including migrating shorebirds. Several important stopover points have been recently identified in both North and South America, and efforts are currently underway to try and preserve the most important of these. The Western Hemisphere Shorebird Reserve Network (WHSRN) has identified 34 wetlands in 7 countries that are critical links for millions of migrating birds.
The articles are very interesting, and provide a wide variety of information
about several ongoing, international programs, and ways for anyone to get
involved, including participation in the International Shorebird Survey
(ISS). There is also several internet sites listed which can provide
pictures
and sounds and an
educational site
for kids and teachers.
During the early 1960's James Mellaart excavated a settlement, in central Anatolia (Turkey), consisting of more than 150 dwellings, many of which contained walls adorned with a variety of art. Mellaart finished his work in 1965 and no work was done at the site, dating to the Early Neolithic (9,000 to 7,500 years ago), until 1993. That is the year Ian Hodder of the University of Cambridge, launched the Çatalhöyük Research Project, a 25-year international and multidisciplinary collaboration with three principle aims: archeological investigation of the site; conservation of architecture, murals, artifacts, and human remains; and management of the site, including interpretive programs for visitors.
The article describes some of the work done over the last 5 years, including the recovery of 67 people who had been buried beneath the floor of one building over the life of its use. Many buildings contain well preserved plaster walls upon which murals, plaster reliefs, and sculptures, as old as 9,000 years, provide unique clues to origins of the various art forms. Microscopic study of the soils and sediments ( micromorphology) has provided an insight to the daily lives of the people who lived at the dawn of human agriculture. Analysis of an open area between buildings has revealed the existence of animal dung and straw, similar to what is found in a modern sheep pen.
During the next 20 years this major research project is sure to answer many questions as to what actually occurred during the important transition as the stone age people living at the end of the last ice age developed into an agricultural based society that could settle year round in one location and form the first cities of human civilization.
The Origin of Birds and Their Flight is an article in the February 1998 issue of Scientific American, written by Kevin Padian and Luis M.Chiappe.
Recent archeological finds in several places around the world since 1990 has provided extremely convincing evidence that all living birds are directly descended from dinosaurs, specifically small Theropod dinosaurs. The first fossil bird skeleton was found in 1861, just two years after Charles Darwin published Origin of Species. This bird, Archaeopteryx, is still the oldest known bird, dated at 150 million years. Up until the 1990's, bird fossils dating to the age of dinosaurs have been very rare. Recent discoveries, both of therapod fossils and younger bird fossils, combined with increased understanding of the biology and genetics of species relationships, has made it possible to trace the lineage.
The article briefly traces the history of scientific knowledge of ancient birds. The authors then systematically trace the changes that slowly transformed these small carnivores into early birds. Light, hollow bones, a wishbone, a backward pointing pelvis, and several other features are unique to theropods and their avian descendants.
You may remember that a few years ago there were several publicized debates in the scientific community about whether birds are descended from reptiles or dinosaurs. This mild uproar resulted from the fact that a reasonably high percentage of scientists, who work in this area, changed opinions from the status quo, to that of accepting the evidence of dinosaur descent. There are still a few holdouts, who generally base their opinion on questions, such as lung development, that the fossil record can not currently answer. Now, it will be interesting to see how long it is before this idea is taught to children in public schools. I'm convinced.
Winter Grays is an article in the Feb. '98 issue of Natural History, written by Gordon Court.
The Great Gray Owl stands nearly one meter (~3 feet) tall, and can hear a mouse walking around under a half meter (~2 feet) of snow from more than 25 meters (~90 feet) away! These highly insulated and intense looking birds of prey inhabit the far northern forests of North America, Asia, and Europe.
The author chronicles studies he and his colleagues have done during the past 3 years in Canada. Unusual surges of owl populations into new areas (known as irruptions) have given the investigators several opportunities to expand our knowledge of these amazing predators. The article briefly describes the owls habitat (woodland, near open areas) and reproductive success. Several excellent photographs display the owl in various aspects of its daily routine.
Thompson's Ice Corps is an article in the Feb. '98 issue of Natural History, written by Mark Bowen.
Glaciers offer scientists a window into past climates. Perpetually frozen for thousands of years, each thin layer provides chemical evidence for atmospheric conditions that existed at the time the deposition of snow occurred.
At the high northern and southern latitudes (polar regions) and at the tops of high mountain peaks around the world, the slow accumulation of snow from year to year adds layer upon layer of winter snow. The temperatures in these locations stay cold enough, even during the summer months, that the snow never melts. After several hundred years, the bottom layers must support the enormous weight of the snow above, and these lower layers become compacted, eventually forming very dense ice. The weight also causes the whole mass to slowly move down slope from the force of gravity.
The glacial layers, while incredibly thin, can still be resolved in the right conditions after as many as 40,000 years, and counted in a manner similar to tree rings to give accurate dates. Anything deposited on the surface, such as a thin layer of dust from a volcanic eruption, can also give clues to the past. For several years, scientists have drilled deep ice cores in the arctic and antarctic, gaining knowledge of a variety of things, like the level of greenhouse gasses, such as carbon dioxide (CO2) and methane (CH4), which existed during the last ice age. This is accomplished by analyzing the microscopic gas bubbles, dust and microbes embedded in the ice.
Last summer, Lonnie Thompson, a paleoclimatologist with Ohio State University, lead an expedition to the top of Bolivia's highest peak, 21,500 foot Nevado Sajama, to obtain ice cores with the hope of unlocking secrets to past climatic fluctuations. This was no easy matter, as the 5 tons of equipment had to be hiked to the summit on foot. Thompson and 5 others lived on the summit for 28 days, a stretch of high altitude survival exceeded only twice before. The author described his few nights on the summit as consisting of thousands of 3 second naps interrupted by desperate gasps for air. Another tricky part was returning the ice cores back to civilization in frozen condition. Initially it was hoped that a hot air balloon could speed the descent, but this proved untenable due to the high winds. Eventually they were successfully carried down by local porters.
This article included a combination of excitement and science, and includes several incredible photos from the expedition.
The Discovery of Gold in California is an article in the January/February issue of California Geology, written by Donald C. Cutter.The first gold rush in CA actually occurred near the start of 1842, in the mountains outside the Pueblo of Los Angeles. The territory was still under Spanish rule and the 'rush' remained a local phenomenon. For this reason and others, the name of the first gold discoverer, Francisco Lopez, remains obscure, while the history books credit James Marshall with the discovery that effectively altered the course of western history.
On January 24, 1848, while Marshall was inspecting work being done on the tailrace of the mill, he noticed a metallic glimmer in the waters of the American River. Using a knife blade, he and several of his workers extricated several ounces of the substance. Marshall returned to Sutter's' Fort so that scientific testing could be applied to his discovery, which of course proved that he had found gold. Though Sutter and Marshall hoped to keep the discovery secret, the first published report was made on March 15, 1848, in The Californian, a weekly San Francisco newspaper. The rest, as they say, is history.
This January marked the sesquicentennial (150 years) of the discovery. A conservative estimate is that by 1865 three quarters of a billion dollars in gold had been mined in CA. This is based on a price of $20.67 per ounce! Gold discoveries continued to be made in the state well into the 20th century, but lagged after WWII. Then, in 1980 the price of gold shot skyward, to $850 per ounce, making it economically feasible to mine large quantities of low grade ore. This, along with improved mining techniques has created another CA gold rush, with production from 1980 to 1997 at about 5 million troy ounces.
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