Failure of dieldrin to affect color vision in juvenile mallard ducks.

Abstract

Nine mallard ducks were raised artificially from eggs and fed the same long-term doses of dieldrin as their parents (0, 4, or 10 ppm); in addition, three ducks from 10 ppm parents were raised on 50 ppm. The parents had been on dieldrin-treated feed for two years. The juvenile ducks were tested at approximately two months of age. Each duck was trained to respond (key peck) differentially to light wavelengths of 552 mµ (S+) and 610 mµ (S−) and, subsequently, was presented 13 different wavelengths, in random order. Differential responding was analyzed for stimulus generalization. No significant differences (p<.05) were found between the control and treated groups' mean stimulus generalization gradients. Only the group receiving 50 ppm in their feed had a mean whole-brain dieldrin residue significantly larger (p<.05) than that of the control group. These results indicate that the ingestion of dieldrin, under the test conditions used, does not have a measurable effect on light wavelength discrimination in mallard ducks.