American kestrels (Falco sparverius) were fed diets containing 0 (control), 1, 3, 10, and 30 μg/g (wet wt) of Kelthane®. Residues of dicofol and its metabolites were then analyzed in the eggs and carcasses of females. Significant differences occurred among treatments for residues of both p,p′‐dicofol and p,p′‐dechlorodicofol (DCD) in both eggs and carcasses and for p,p′‐dicholorbenzophenone (DCBP) in eggs. Residue concentrations increased with increasing treatment exposure. Residues of p,p′‐dicofol, p,p′‐DCD, and p,p′‐DCBP in eggs were significantly correlated with eggshell quality parameters. Significant correlations also occurred among contaminants in eggs and for individual contaminants between eggs and carcasses. The lowest‐observed‐dietary‐effect concentration for eggshell thinning was 3 μg/g, whereas 1 μg/g may be considered to be near a no‐observable‐adverse‐effect concentration. Concentrations of dicofol in potential prey items and eggs of wild birds generally have been lower than dietary‐effect concentrations or concentrations in tissues or eggs associated with eggshell thinning and reduced reproductive success.
