Man, was I lied to from the sixties?
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VII. Bald eagles
DDT was blamed for the decline in the bald eagle population.
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Bald eagles were reportedly threatened with extinction in 1921 -- 25 years before widespread use of DDT.
[Van Name, WG. 1921. Ecology 2:76]
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Alaska paid over $100,000 in bounties for 115,000 bald eagles between 1917 and 1942.
[Anon. Science News Letter, July 3, 1943]
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The bald eagle had vanished from New England by 1937.
[Bent, AC. 1937. Raptorial Birds of America. US National Museum Bull 167:321-349]
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After 15 years of heavy and widespread usage of DDT, Audubon Society ornithologists counted 25 percent more eagles per observer in 1960 than during the pre-DDT 1941 bird census.
[Marvin, PH. 1964 Birds on the rise. Bull Entomol Soc Amer 10(3):184-186; Wurster, CF. 1969 Congressional Record S4599, May 5, 1969; Anon. 1942. The 42nd Annual Christmas Bird Census. Audubon Magazine 44:1-75 (Jan/Feb 1942; Cruickshank, AD (Editor). 1961. The 61st Annual Christmas Bird Census. Audubon Field Notes 15(2):84-300; White-Stevens, R.. 1972. Statistical analyses of Audubon Christmas Bird censuses. Letter to New York Times, August 15, 1972]
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No significant correlation between DDE residues and shell thickness was reported in a large series of bald eagle eggs.
[Postupalsky, S. 1971. (DDE residues and shell thickness). Canadian Wildlife Service manuscript, April 8, 1971]
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Thickness of eggshells from Florida, Maine and Wisconsin was found to not be correlated with DDT residues. "
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