Wednesday, February 13, 2008
Brown Pelican May Come off Endangered Species List
The Department of Interior is considering removing brown pelican from endangered species list.Brown pelicans were placed on the endangered species list about 40 years ago because their population crashed due to DDT poisoning. DDT is metabolized in birds into a compound known as DDE. DDT and DDE are fat-soluble and large amounts would be deposited in eggs, and the fatty tissues of the birds.
Pelicans and other birds like the bald eagle, and peregrine falcon are at, or near the top of their food webs. DDT, because it is fat soluble, and is stored in the fat of animals “bio magnifies” as it moves up the food chain. In other words as these birds near the top of the food chain consume their prey they also consume the DDT stored in the fatty tissues of their prey. Their prey in turn store the DDT consumed in their food. DDT caused the eggshells of these birds to become so thin that when the adults sat on the eggs to incubate them, the eggs were crushed. Brown pelicans in California nest on the channel islands, including Anacapa and Santa Barbara. Despite thousands of birds laying eggs, in some years no chicks at all survived.
In 1972 DDT was banned in the US. Since then there has been a gradual recovery in the numbers of pelicans and peregrine falcons. The peregrine was removed from the endangered species list in 1999. The bald eagles, which used to nest on Catalina have not done as well. There are still high concentrations of DDT in some fish and birds in this area due to the massive dumping of wastes full of DDT into the waters off San Pedro by the Montrose Chemical Company.
There are estimates of as many as 600,000 brown pelicans through out the US currently. The birds also are found off the Gulf Coast and nest on low-lying islands off the coast of Louisiana. However, these islands are vulnerable to damage from coastal storms, and inundation due to the rise in sea level.
During the winter and spring brown pelicans can commonly be seen at Bolsa Chica here in Huntington Beach.