Analyses of bald eagles that died of DDT poi- 

 soning in experimental studies in Alaska were 

 completed in 1961. The most significant result 

 was that the brains of these eagles contained very 

 similar quantities of DDT despite differences in 

 dosage levels and times imtil death. Thus, read- 

 ings of brain levels are shown to be an important 

 clue to DDT poisoning. The tabulation below 

 compares the residue level in tissues of the five 

 birds having the highest dosages. 



1 Dry-weight basis, on assumptioa of 70 percent moisture content in diet. 

 ' Residues, prtmarily DDT and DDD, colorimctrically determined. 



Pesticide residues in water birds. — Specimens 

 of approximately 50 water birds were collected 

 along the lower Mississippi and Atchafalaya 

 Rivers during 1964 by the Louisiana Cooperative 

 Wildlife Research Unit in cooperation with per- 

 sonnel of the Bureau's Division of Management 

 and Enforcement. The collection included egrets, 

 gulls, lierons, rails, terns, willets, and single speci- 

 mens of yellowlegs, ibis, dowitcher, gallinule, and 

 grebe. Pesticide residues in the vital organs and 

 fat of the specimens were measured at the Feed 

 and Fertilizer Laboratory. Louisiana State 

 University. 



DDT or its degradation products were present 

 in the fat of 18 specimens, the levels ranging from 

 0.1 to 427 ppm. (10 ppm or more in 5 of the 18). 

 Dieldrin was detected in the fat of six specimens, 

 the levels ranging from 0.1 to 0.8 ppm. The levels 

 of endrin in seven specimens ranged from trace 

 amounts to 4.7 ppm. Detectable amoimts of hep- 

 tachlor expoxide (0.1 to 1.8 ppm), DDD (trace 



In studying the effects of pesticides on birds of prey under controlled conditions, a small, tractable species is easiest 

 to handle and most economical to maintain. Accordingly, the Patnsent Center has developed a breeding colony 

 of sparrow hawks, a species readily adaptable to pen conditions. They will be used for the more routine aspects 

 of pesticide research with birds of prey. (Photo by Rex G. Schmidt) 





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