There is a story on CBSNews.com that I believe ran on the TV yesterday about the recovery of the bald eagle and whether it should be removed from the endangered species list. Mentioned OVER and OVER in the story is role of the pesticide DDT in the decline of the bald eagle population.
In case anyone else watches this bit I wanted to clarify a few things. There has never been a confirmed death of a bald eagle attributed to DDT. The bald eagle populations in the US had already begun to recover during the height of DDT use. There is, however, proof that bald eagle populations declined rapidly to to overhunting.
The DDT-eagle link is another story cooked up by environmentalists to fuel their anti-chemical pesticide crusades. The first correlations between DDT and bird eggs were made by the now infamous Rachel Carson in her book "Silent Spring", named such for the lack of chirping birds in the novel...they were killed by pesticides. It has become something of an enviro Mein Kampf.
Curious is the fact that this story runs not a week after the WHO publicly endorses the use od DDT to fight Malaria in the poorest nations of Africa. Makes you ponder who has ties to what extremist groups at that station. Once again the mainstream media shows it is as biased as the politicians it criticizes.
Here are the facts about bald eagles and DDT, you can read more about DDT by going here:
http://www.junkscience.com/ddtfaq.htm#
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.
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[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.
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[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.
Data from Krantz, WC. 1970. Pesticides Monitoring Journal 4(3):136-140.
State Thickness (mm) DDE residue (ppm)
Florida 0.50 About 10
Maine 0.53 About 22
Wisconsin 0.55 About 4
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U.S. Forest Service studies reported an increase in nesting bald eagle productivity (51 in 1964 to 107 in 1970).
[U.S. Forest Service (Milwaukee, WI). 1970. Annual Report on Bald Eagle Status]
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U.S. Fish and Wildlife Service biologists fed large doses of DDT to captive bald eagles for 112 days and concluded that "DDT residues encountered by eagles in the environment would not adversely affect eagles or their eggs."
[Stickel, L. 1966. Bald eagle-pesticide relationships. Trans 31st N Amer Wildlife Conference, pp.190-200]
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Wildlife authorities attributed bald eagle population reductions to a "widespread loss of suitable habitat", but noted that "illegal shooting continues to be the leading cause of direct mortality in both adult and immature bald eagles."
[Anon.. 1978. U.S. Fish and Wildlife Service, Endangered Species Tech Bull 3:8-9]
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Every bald eagle found dead in the U.S., between 1961-1977 (266 birds) was analyzed by U.S. Fish and Wildlife Service biologists who reported no adverse effects caused by DDT or its residues.
[Reichel, WL. 1969. (Pesticide residues in 45 bald eagles found dad in the U.S. 1964-1965). Pesticides Monitoring J 3(3)142-144; Belisle, AA. 1972. (Pesticide residues and PCBs and mercury, in bald eagles found dead in the U.S. 1969-1970). Pesticides Monitoring J 6(3): 133-138; Cromartie, E. 1974. (Organochlorine pesticides and PCBs in 37 bald eagles found dead in the U.S. 1971-1972). Pesticides Monitoring J 9:11-14; Coon, NC. 1970. (Causes of bald eagle mortality in the US 1960-1065). Journal of Wildlife Diseases 6:72-76]
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U.S. Fish and Wildlife Service biologists linked high intake of mercury from contaminated fish with eagle reproductive problems.
[Spann, JW, RG Heath, JF Kreitzer, LN Locke. 1972. (Lethal and reproductive effects of mercury on birds) Science 175:328- 331]
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Shooting, power line electrocution, collisions in flight and poisoning from eating ducks containing lead shot were ranked by the National Wildlife Federation as late as 1984 as the leading causes of eagle deaths.
[Anon. 1984. National Wildlife Federation publication. (Eagle deaths)]
