|MadSci Network: Zoology|
Greetings, Below you will find the answer to both of your questions concerning baby pelicans and what happens to birds when it storms. The question of where birds go when it storms was previously answered on the Mad Sci Network. I have included the message number so you can look up the answer for a different perspective. http://www.shoalhaven.net.au/inews/bushtele/btpg1.html Ever Seen a Baby Pelican? As one ponders these extraordinary birds which are a regular feature of our waterways, it is hard to imagine what a baby pelican looks like. Where do they nest? Why do we never see them paddling behind the adults as we so often see with other waterbirds? Pelicans nest in colonies, usually on isolated islands away from ground predators. The breeding pair share the tasks of building the nest, incubation and feeding the young. The nest, a crude platform of sticks lined with grass or seaweed, usually contains 2-4 eggs. Pelicans from the Shoalhaven may travel great distance to undisturbed nesting sites and it is only when the young are strong enough to fly that they are able to return to the area. The Pelican Anyone who has observed this magnificent bird in close-formation flight, just brushing the waves as it scavenges the last bit of lift from the wind, must conclude that nature far exceeds man in understanding aeronautical design. The bird is huge, sometimes with a wing expanse of nearly 10 feet, and the head, outstretched and the neck neatly drawn up, belies the presence of the pouch which can if fully extended and wide stretched, encompass a fish weighing over a pound. And yet in flight, all this is obscured as it gracefully glides alone, in pairs or small groups of birds that are perhaps related or perhaps not. And if this is not enough, a gull may be accompanying the pelican(s). At once the gull is an ever-present companion, there to rob the pelican of its newly captured fish or if returning to the nesting area to prey on eggs and the defenseless young. It has been said that the pelican uses its large, thin, skinny bag that hangs beneath its bill to dip-net small fish. In observing white pelicans in the race waters below the dam at Lewis and Clark lake on the Missouri River, it does appear that they are active in the water perhaps catching confused or injured fish that have passed through the turbines. They swim in perfect formation, not unlike their patterns in flight. A lead pelican dips its head beneath the water and in synchrony, the others follow him in searching the clear cold water for today's meal. How successful they are is impossible to judge. With head raised, water drained from the pouch, the point pelican returns to its vigilant role awaiting the next fish. As pointed out in the book, Birds in America, while it was once thought the pelican could convey live fish via the extended pouch, this was questioned by Audubon who pointed out that it is doubtful that the pelican could fly at all with his burdensome pouch so out of trim. The brown pelican is perhaps the most familiar of the some ten species that exist. This is the common pelican of Florida, the Gulf and Atlantic coast. This is the bird that we see crashing down from a height of 10 to 50 feet into the waves. He is often successful in capturing his prey, as upon emerging from the deep, he is seen to pause sometimes for up to a minute, then raise his head, straightening his neck and with a quick motion, rearranging his catch so that it can be easily swallowed. Anyone that has tried to spot fish in the water, regardless of angle, distance or lighting, must be awed by the vision of this strange creature. How can it see the fish, determine the depth, direction in which it is swimming, size (for a fish too large is of no value), and perhaps variety; and then plunge headlong with wings folded to increase speed and reduce impact upon entering the water; catch the fish; and bob to the surface. Amazing! But on land (a convenient post, tree limb or sign will do) the pelican reveals itself in all its ugliness. It is ungainly, if not uncouth. As it preens itself, the beak carefully arranges feathers wet by a recent dunking. But no matter how it tries, it cannot obscure the fact that it is truly ugly. The thin, large, skinny bag that hangs from the lower part of the bill has been said to be quite considerable in its capacity, and it dangles like a dowagers wrinkled neck. It does not add any to the attractiveness of this bird. And if this is not enough, just like our own species, as it passes through puberty; in the case of the pelican at the beginning of breeding season, the pelican develops an enormous zit (called a excrescence by birders) on its upper mandible (nose if you prefer). William Finley wrote in Birds of America; "The first time I ever saw a motley crowd of half-grown pelicans, I thought Nature had surely done her best to make something ugly and ridiculous. It was a warm day and the birds stood around with their mouths open, panting like a lot of dogs after a chase, their pouches shaking at every breath. When I went near, the youngsters went tottering off on their big webbed feet with wings dragging on this side and that, like poorly handled crutches. The youngsters huddled together by hundreds in a small place. Those on the outside pushed and climbed to get near the center. till it looked worse than any football scrimmage I ever saw." If one looks at the immature pelican, one is reminded of a plucked chicken, ready for the boiling pot. But, the large head, extended neck and duck like feet remind you that this is not an ordinary bird." Finley further wrote; "One might wonder how such a huge-billed bird as a Pelican could feed helpless chicks just out of the egg. It was done with apparent ease. The old bird regurgitated a fishy soup into the front end of his pouch (wonder how Finley identified the bird as male?) and the baby Pelican pitched right in and helped himself out of this family dish. As the young bird grew older and larger, at each meal he kept reaching farther into the big pouch of his parent until finally, when he was half- grown, it was a most remarkable sight. The mother opened her mouth and the whole head and neck of her nestling disappeared down the capacious maw, while he hunted for his dinner in the internal regions." The fishing habits of the white pelican and the familiar brown pelican of Florida&rsquos waters are distinctly different. So the following is a research proposal that I hope will find interest to birders, as it will help distinguish whether the individual bird is pressed to accept the practices of its nest mates or whether it is inborn, imprinted in the pelican&rsquos DNA and immutable. Imagine if you will. Eggs of the brown pelican are placed in a nest having white pelican eggs and the nesting bird is a white pelican. Upon hatching, will the mother bird accept this strangely coloured transplant or will it be ignored. Once having reached maturity will the brown pelican use the same fishing techniques of the white pelican or will it revert to the practice of a soaring flight, plummeting dive and capture familiar with its genetic parents. Likewise, will a white pelican egg when hatched in the presence of brown pelicans be accepted by its mothering hen or will it be refused food. Will it when mature revert to the practice of swimming and catching fish by a quick duck of the head into the water. This proposal of observing the habits of the pelicans will be much more informative than those where a migratory bird egg is nested with a companion species, as example the whooping crane with the sandhill cranes. Joe Wortham&rsquos Home Page , About Joe Wortham January 30, 1999 http://www.usd.edu/~jwortham/jay/pelican.html http://biology.usgs.gov/pr/newsrelease/1996/9-13.html Wildlife and Storms Release 13 September 1996 Debra Becker 703-648-4461 NBS Scientists Find Wildlife Impacts During Severe Storms, But Nature Rebounds What happens when a hurricane threatens? Homeowners and vacationers in the path of the storm may be able to protect their homes and travel to safety, but some wildlife may not be so fortunate. Scientists at the National Biological Service have found over the course of many years of research that, though there may be some structural changes in the habitat and populations may suffer drastic losses, most plant and animal populations living in storm zones are able to survive and recover in time from the severe weather. Immobile species such as mussels and oysters may be locally wiped out in the impact zone. Some of these species can be transported with the debris of the hurricane to distant locations along the coast and inland, often to habitats where survival may be difficult if not impossible. Upland terrestrial habitats can be flooded or totally inundated, washing away or drowning their resident fauna, especially small mammals such as rabbits and mice. Nesting rookeries, including the eggs and young, of colonial water birds (herons, seagulls, pelicans) can be completely destroyed. NBS scientists and their collaborators found that the Louisiana fishery and aquaculture industry suffered enormous losses as a result of Hurricane Andrew in 1992. An estimated 184 million fish were killed in south Louisiana's Atchafalaya Basin alone. Andrew's winds caused widespread defoliation (leaf removal) of trees and shrubs, resulting in a large influx of organic material (leaves) into the wetlands in a short period. This rotting material caused extremely low levels of oxygen in the water, suffocating the fish. At the same time, 25 percent of Louisiana's public oyster seed grounds were virtually wiped out by Hurricane Andrew. These and other bottom- dwelling organisms -- which provide an important food source for wading birds on Louisiana's Barrier Islands -- suffered mass mortalities during the passage of Hurricane Andrew. Hurricane Hugo wreaked similar devastation on the Puerto Rican parrot population. Approximately half of this critically endangered population of less than 50 birds was lost. In some cases the birds were killed as a result of the storm, while in others the changes in the habitat as a result of the storm made the birds more vulnerable to predators. Scientists believe that Puerto Rican parrots that survived possibly roosted in the cavities of large, strong, hurricane- resistant trees, such as the tabonuco tree of the Caribbean National Forest. One NBS scientist observed songbirds on the ground and under cover during Hurricane Hugo, sitting tight until the storm passed. Others may have been blown out to sea and perished. Oceanic birds have appeared in strange places after storms, having been wind-carried miles inland. The same is true for inland birds blown out to sea. These birds would perish unnoticed in the deep oceans. Some of the inland birds might find temporary refuge and rest on ships, but without food it is doubtful these birds would survive more than 24 to 48 hours. Manatees, large marine mammals, are well adapted to the aquatic environment. Because they inhabit nearshore and inland waters, they can usually locate sheltered areas during stormy weather. The only known case of a manatee experiencing difficulty during a storm occurred when Hurricane Andrew swept across south Florida. This huge storm caused high winds and tides along the shoreline of Biscayne Bay. After Andrew passed, a manatee was discovered in a football-field sized pond on a golf course in South Miami, about a half-mile from the bay. This animal was rescued by NBS scientists, who determined that she was in good health and then released her back into Biscayne Bay. Stream organisms are usually well adapted to all but the most severe floods. Freshwater mussels will remain burrowed into bottom sediments and are usually in larger, lower gradient streams where rocks and other sediments are not picked up and moved during periodic floods. At these times fish are known to seek shelter in calm waters immediately behind large rocks or other obstructions in the stream. Even when whole generations of stream insects are washed away in a flood, there are usually survivors that persist to recolonize and repopulate the stream by the next generation. NBS scientists at the Florida Caribbean Science Center in Gainesville, Florida found that the effects of Hurricane Opal (October 1995) on the endangered Okaloosa darter (a small fish) were positive. Scientists have been involved in monitoring the population of the Okaloosa darter in the six stream systems it inhabits in northwest Florida for the last eight years. They have 12 permanent study sites that they visit twice annually. Nearly all of these study sites were subjected to the extreme winds and flood conditions of the category 3 hurricane. Streams were criss-crossed with fallen trees every 10 meters or so. This increased number of fallen trees changed the typical stream current patterns that had been previously observed. It seems that the amount of area with cover increased around the downed logs. From other isolated flood situations that were examined, it appeared that as flows increased, the size and number of eddies increased. These eddies provided the Okaloosa darters with refuge from severe weather conditions and the fish were found in slightly greater numbers after the hurricane than before. Occasionally a severe "1000 year flood" will occur that drastically alters the stream habitat and wipes out its biota. Such an event occurred in the Shenandoah National Park June 25-27, 1995. More than 14.5 inches of rain were measured during a 48-hour period, with larger though unmeasured amounts of rainfall estimated in isolated drainages in the park. Stream habitats in Virginia's Staunton River were totally obliterated by the floods -- mature trees were uprooted and washed downstream with large boulders during this flood. All of the streams' fish and insects were destroyed, and the recovery time of the system is estimated in decades or longer as streamside vegetation and soils reestablish. Such washout events are known to occur every few dec Service of the U.S. Department of the Interior is dedicated to providing fuller documentation and understanding of the dynamic living resources of the nation. The agency is slated to become the Biological Resources Division of the U.S. Geological Survey on October 1, 1996. The following is the ID for the question of birds and storms. Re: This may seem silly , but, How do birds survive storms. Date: Fri Oct 23 14:20:20 1998 Posted By: Dave Williams, Science Department Chair, Valencia Community College Area of science: Zoology ID: 906855550.Zo Thanks for taking the time to send in a question to the Mad Sci Network June Wingert Associate Scientist Lexicon Genetics The Woodlands, Texas
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