Brown Pelican
The brown pelican (Pelecanus occidentalis) is a large water bird of the family Pelicanidae that is found along both coasts of the United States, chiefly in saltwater habitats. It weighs up to 8 lb (3.5 kg) and has a wingspan of up to 7 ft (2 m). This pelican has a light brown body and a white head and neck often tinged with yellow. Its distinctive, long, flat bill and large throat pouch are adaptations for catching its primary food, schools of mid-water fishes. The brown pelican hunts while flying a dozen or more feet above the surface of the water, dropping or diving straight down into the water, and using its expandable pouch as a scoop or net to engulf its catch.
Both east and west coast populations, which are considered to be different subspecies, have shown various levels of decline over the later part of the twentieth century. It is estimated that there were 50,000 pairs of nesting brown pelicans along the Gulf coast of Texas and Louisiana in the early part of the twentieth century, but by the early 1960s, most of the Texas and all of the Louisiana populations were depleted. The main reason for the drastic decline was the use of organic pesticides, including DDT and endrin. These pesticides poisoned pelicans directly and also caused thinning of their eggshells. This eggshell thinning led to reproductive failure, because the egg were crushed during incubation. Louisiana has the distinction of being the only state to have its state bird become extinct within its borders. In 1970 the brown pelican was listed as endangered throughout its U.S. range.
During the late 1960s and early 1970s, brown pelicans from Florida were reintroduced to Louisiana, but many of these birds were doomed. Throughout the 1970s these transplanted birds were poisoned at their nesting sites at the outflow of the Mississippi River by endrin, which was used extensively upriver. In 1972 the use of DDT was banned in the U.S., and the use of endrin was sharply curtailed. Continued reintroduction of the brown pelican from Florida to Louisiana subsequently met with greater success, and the Louisiana population had grown to more than 1,000 pairs by 1989. Although the Texas, Louisiana, and California populations are still listed as endangered, the Alabama and Florida populations of the brown pelican have been removed from the federal list due to recent increases in fledgling success. In 2002, taking the Louisiana populations off of the endangered listing is being considered. There are currently 16,4000 nesting pairs and 35,000 young in that state. The Texas population has only 2,400 pairs.
Other problems that face the brown pelican include habitat loss, encroachment by humans, and disturbance by humans. Disturbances have included mass visitation of nesting colonies. This practice has been stopped on federally owned lands and access to nesting colonies is restricted. Other human impacts on brown pelican populations have had a more malicious intent. On the California coast in the 1980s there were cases of pelicans' bills being broken purposefully, so that these birds could not feed and would ultimately starve to death. It is thought that disgruntled commercial fishermen faced with dwindling catches were responsible for at least some of these attacks. The brown pelican was a scapegoat for conditions that were due to weather, pollution, or, most likely, overfishing.
Recovery for the brown pelican has been slow, but progress is being made on both coasts. The banning of DDT in the early 1970s was probably the turning point for this species, and the delisting of the Alabama and Florida populations is a hopeful sign for the future.
Resources
Books
Ehrlich, P., D. Dobkin, and D. Wheye. Birds in Jeopardy. Stanford, CA: Stanford University Press, 1992.
Periodicals
Schreiber, R. W. "The Brown Pelican: An Endangered Species?" BioScience 30 (November 1980): 742–747.
Tompkins, Shannon. "Brown Pelicans Reappearance Proves Lessons can be Learned." Houston Chronicle (February 14, 2002) [cited May 2002]. <http://www.chron.com/cs/CDA/sto ry.hts/outdoors/tompkins/1256525> ;.
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