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Wild Bird Profiles-Pelican
The eight species of pelicans come in many sizes and colors. The smallest pelican is the American Brown Pelican (Pelecanus occidentalis), with a wingspan of approximately 6 feet (3 meters). The largest is the Dalmatian Pelican (Pelecanus crispus), a thirty-pound bird with a wingspan nearly double that of the Brown Pelican. Scientists loosely group pelicans based on the color of their adult plumage, specifically brown or white. The brown pelican sub-group consists of the Pink-backed, Brown, Peruvian, and Spot-billed Pelicans, which also generally build platform nests in trees. The white pelicans consists of the Australian, Dalmatian, American White, and Great White Pelicans, which generally nest on the ground. Pelicans are accomplished swimmers and feed primarily on fish, although some populations have adapted to take advantage of other food sources. Pelicans possess large webbed feet that allow them to propel themselves while sitting on the water's surface. The pelican's distinctive throat pouch is used to snap up fish, water included, and the birds must compress their pouch and drain the water before they can swallow. One population of Great White pelicans who inhabit the island of Dassen in South Africa have been observed exhibiting an unprecedented feeding behavior. The pelicans' main food source, sardines, have been overfished in the waters surrounding the island, and this food shortage has forced the resident pelicans to change feeding tactics. Driven by hunger, a squadron of pelicans flies to the nearby island of Malgas, on which nests a large population of Cape Gannets, a smaller sea bird in the same order as the pelicans. Looking grossly out of proportion among so many smaller white birds, the larger white pelicans stride through the colony, pick off any unguarded gannet chicks small enough to fit into their mouth, and swallow them whole. These birds have also been documented eating the chicks of nesting seabirds on Dassen Island, including cormorants, African penguins, gulls, and terns. Pelicans, although common worldwide, have been impacted by many human-caused environmental problems. Brown Pelicans were especially vulnerable to the effects of DDT from 1950 to 1980, partly because the birds essentially stand on their eggs to incubate them. The thinned shells broke under the parents' weight, and the population of this species declined dramatically. Pelicans are also often one of the species most sensitive to oil spills and coastal storms. In 2006, Hurricane Katrina decimated a rookery of 60,000 pelicans in the Gulf of Mexico. In 2010, the same rookery was again impacted by the Deepwater Horizon oil spill. Worldwide, these birds are caught regularly by pelagic long lines, and are entangled in fishing gear. Thankfully, pelicans are hardy birds, and their populations, as well as individuals, continue to beat the odds. About the Author: Photo: http://www.dreamstime.com/Jeffplay_info Watch PGAA for future birding articles from YourBirdOasis
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