Brown pelicans not harmed by DDT either

Thanks to Florida journalist Charles Sobczak for the opportunity to debunk another DDT myth.

The Sanibel-Captive Island Leader reports,

…Widespread use of DDT to control the Florida mosquito population altered the calcium metabolism in pelicans and other birds, causing them to produce eggs with shells too thin to support the embryo to maturity. In nearby Louisiana (where, ironically, the pelican is the state bird) the population completely collapsed because of the overuse of these pesticides. Louisiana had to import Florida pelicans through the 1980s to help rebuild its decimated flocks. Today, they are once again rebounding from yet another manmade disaster, the Deepwater Horizon oil spill…

But check out the following from’s “100 Things You Should Know About DDT“:

92. Brown pelicans declined in Texas from a high of 5,000 birds in 1918 to a low of 200 in 1941, three years before the presence of DDT. [Pearson TG. 1919. Review of reviews. Pp. 509-511 (May 1919); Pearson TG. 1934. Adventures in Bird Protection, Appleton- Century Co., p. 332; Pearson TG. 1934 (Discussion of 1918 survey) National Geographic pp. 299-302 (March 1934); Allen RG. 1935. Auk 52: p.199;]

93. Disappearance of the brown pelicans from Texas was attributed to fisherman and hunters. Gustafson AF. 1939. Conservation in the United States, Comstock Publ. Co., Ithaca, NY. (Repeated in U.S. Fish and Wildlife Service Report No. 1, 1970)]

94. Brown pelicans experienced no difficulty in reproducing during the DDT years. [See Banks, RC. 1966. Trans San Diego Soc Nat Hist 14:173-188; and Schreiber RW and RL DeLong. 1969. Audubon Field Notes 23:57-59]

95. Brown pelicans did suffer reproductive problems following the 1969 Santa Barbara oil spill. Oil on eggs is a known cause of embryo death. [See e.g., National Wildlife Federation . 1979. Embryonic mortality from oil on feathers of adult birds. Conservation News, pp. 6-10 (October 15, 1979); Hartung, R. 1965. (Oil on eggs reduces hatch ability by 68 percent). J Wildlife Management 29: 872-874; King, KA 1979. (Oil a probable cause of pelican mortality for six weeks after spill). Bull Environ Contam. Toxicol 23:800-805; and Dieter, MP. 1977. (5 micro liters of oil on fertile egg kills 76 percent to 98 percent of embryos within. Interagency Energy-Environment Research and Development Program Report, pp 35-42]

96. Among brown pelican egg shells examined (72 percent), there was no correlation between DDT residue and shell thickness. [Switzer, B. 1972. Consolidated EPA hearings, Transcript pp. 8212-8336; and Hazeltine, WE. 1972. Why pelican eggshells are thin. Nature 239: 410-412]

97. An epidemic of Newcastle disease resulted in millions of birds put to death to eradicate the disease. [United Press International. “Newcastle disease epidemic in California (April 1972)] The epidemic among U.S. birds was caused by the migration of sick pelicans along the Mexican coast. [Hofstad MC. 1972. Diseases of Poultry. Iowa State Univ. Press]

2 thoughts on “Brown pelicans not harmed by DDT either”

  1. Every reference listed is written by special interest money. The amount of disinformation that has been brought forth in a smear campaign would do citizens united proud. I live on the Texas coast. I’m old enough to remember seeing a pelican as a rare treat. DDT was banned for good reason.

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