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keeping clear of the beaches that the knots rely on during migr Unfortunately missed the program, but I had a mild comment on the species-ist emphasis here (sent it earlier but it didn't do through). Nothing against the Red Knot and of course I hope it survives, but the received vertebratocentric perspective on this is interesting. As the blurb below states, there are lots of other similar peep species around, but the horseshoe "crab" Limulus polyphemus is a unique species here and has been practically wiped out in many of its former habitats on the US East coast, according to Bob Barlow, a former student of Hartline (see below) who still works on it, latterly on its visual behaviour under water. Apparently the market for its blood is the main reason for the punitive "harvesting". Besides having a far more interesting, ancient lineage, Limulus has contributed to several outstanding scientific discoveries in vision science, notably that of "lateral inhibition" by which the nervous system sharpens up percepts, enhancing edge-detection in images. This has emerged as a common enhancing operation elsewhere in nervous systems, but originally came mainly out of work on the compound eyes of Limulus in the 40s-60s -- netting a Nobel prize for H.K. Hartline, of the then Rockefeller Inst (now Univ). In the 60s, S. Yeandle made the first recordings of single photon captures in the same eye (since then recorded in vertebrates, though not in Red Knots), while in the 70's, the first detailed analyses of how photoreceptor currents work (semi-universal) came out of measurements on huge photoreceptor cells in the ventral nerve that had been thought before this to be an olfactory structure (analysed since in vertebrates, though not in Red Knots). Circadian rhythm mechanisms are big news at present (molecular mechanisms), and one of the best analyses of the circadian control of an eye by the brain came from Barlow and colleague's work on the Limulus lateral eyes. There are at least two other sets of eyes in horseshoe crabs, one UV sensitive and one in the telson... None of these conceptual advances were minor cul-de-sacs and all have become incorporated into the neuroscience base, ever expanding. Limulus deserves great respect as a unique and unusual pioneer invertebrate animal that ought to survive. What has the Red Knot done to gain comparable respect? So, if I had to curry up votes for one of the two endangered species, it would be for the unique and illustrious horseshoe crab, first. "Why save the Red Knot?" indeed -- do it second. Steve ****************************************** Quoting Elizabeth Doull <edoull@ns.sympatico.ca>: > Why save the Red Knot? > PBS > flocks of shorebirds, the red knot is fairly average looking. In > fact, only the most practiced bird watchers may be able to > distinguish this medium-sized, plump peep from the thousands of other > shorebirds playing tag with the waves. Yet, somehow the red knot has > caught the attention of people around the world. > > The knot's dependence on the eggs of the heavily harvested horseshoe > crab has placed it at odds with another species -- humans. > Conservation groups, lawmakers, fishermen, scientists, and ordinary > citizens have all entered the debate. But even as our actions have > imperiled the red knot, we can also preserve the species, by > regulating the fishing industry and keeping clear of the beaches that > the knots rely on during migration. Where nature ranks in our system > of values will dictate how far we are willing to go to protect the > red knot. > > There are millions of shorebirds in the world. Why all the clamor > over the red knot? How could this small bird stir up so much > controversy and inspire such extraordinary efforts on its behalf? To > begin to answer these difficult questions we must first become > familiar with the red knot. > > The red knot may blend in with the other small shorebirds, but it > makes a journey that certainly sets it apart. A master of > long-distance aviation, the red knot makes one of the longest > migratory trips of any bird -- 9,300 miles along the Atlantic flyway > from its wintering grounds in southern South America to its high > Arctic breeding grounds. The journey is so exhausting, it requires > two to three stopovers for refueling. The horseshoe crab egg feast > they will consume at Delaware Bay, is not just an indulgence -- it's > absolutely crucial for the birds' survival. When the knots arrive at > Delaware Bay, their bodies are half their starting weight, devoid of > fat and even some muscle. Here, the red knot will take about two > weeks to double its weight so it can continue its migration. > > The migratory trip is far from the only risk the peeps take in their > lives. The life of the red knot is fraught with challenges. In their > wintering grounds of Tierra del Fuego, blinding gales blow up without > warning, and tides surge 25 and 35 feet every 12 hours. The > challenges facing the knots are even greater on the Arctic nesting > grounds, where a declining population of birds makes it more > difficult to find a mate and even if they do, a snowstorm can wipe > out the knots' eggs. If the birds don't consume enough eggs during > their migratory stopover, they may not have enough fuel to complete > their trip, and those undernourished knots that do make it to the > Arctic will arrive weak and emaciated. Add the fierce and > unpredictable Arctic weather into the mix, and the birds are likely > to be in such a state that it is nearly impossible for them to raise > chicks. > > Researchers tag red knots in 'Crash: A Tale of Two Species.'Nature, > it seems, has really stacked the deck against this creature. During > its migration, the red knot concentrates in huge, densely-packed > flocks. These enormous gatherings make the knots vulnerable to > habitat destruction and, in South America, hunting pressure. Sadly, > it is not just their eating preferences but their social patterns > that put them at odds with human activities. > > All of these hardships have given rise to dire statistics. The red > knot is a creature in peril. The U.S. Shorebird Conservation Plan > lists the red knot as a "Species of High Concern," based on declining > population trends and threats on non-breeding grounds. In the last 20 > years red knots have declined from over 100,000 to less than 15,000. > And in 2006, the knot was named a candidate for Endangered Species > Act protection as an emergency measure to slow the rapid fall of its > population. In the Delaware Bay, the knot has suffered a decline so > severe that some experts predict the population stopping over at the > bay could disappear within five years. > > Studies conducted outside of the U.S. do not paint a brighter > picture. Counts of knot populations wintering in South America > dropped over 50% from the mid-1980s to 2003. Researchers have > suggested that the continued hunting of knots in South America might > be partly to blame. > > The red knot is one of the world's most amazing birds. But if that is > not sufficient motivation for us to save it, there are other > incentives. Chincoteague, Virginia, a popular stop-over for the red > knot, finds that what is good for migratory shorebirds is also good > for Virginia business. A recent tourism survey found that birders and > ecotourists were bringing in significant amounts of resources to the > local economy. And one economic study in South Jersey found that the > shorebird-watching industry generated nearly $36 million dollars in > revenue for the area. > > Sadly, the issue raised in "Crash: A Tale of Two Species" over the > increased harvest of horseshoe crabs remains contentious today. > Whether the red knot will be able to continue to use Delaware Bay as > a major migratory staging area in the future is still up in the air > -- as is the fate of the knot. > > For more information on red knot conservation efforts, visit > http://shorebirdproject.blogspot.com/, where Larry Niles (featured in > "Crash: A Tale of Two Species") and an international team of > scientists blog about the most recent news on the red knot.
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