DDT, Chlordane, Toxaphene and PCB Residues in Newport Bay and Watershed: Assessment of Hazard to Wildlife and Human Health - Reviews of Environmental Contamination and Toxicology - page 123

Mendenhall and Prouty ( 1978 ) studied recovering populations of brown pelicans
in South Carolina. A steady decline in DDE residues in eggs had a high negative
correlation with increasing eggshell thickness (Fig. 20 ). Eggshell thickness in 1978
was only 6% below the pre-1947 mean thickness. Fledgling rates continued to
increase and reached a population sustaining level in 1976 (Table 26 ). The authors
noted that in 1977 all eggs sampled were below 2.5 ppm DDE. DDE levels above
2.5 ppm had been associated with consistent nest failure.
Fig. 20 Negative correlation between egg DDE residue and shell thickness for South Carolina
brown pelicans. Figure 1 in Mendenhall and Prouty ( 1978 ) reproduced with permission
Table 26 Recovery of reproductive success in brown pelicans from South Carolina from 1969 to
1978. Table 3 in Mendenhall and Prouty ( 1978 ) reproduced with permission