|Abstract or Summary
- Prior to onset of the breeding season, a ration containing 18.4 mg/kg N-(Ethylmercuri)-p-toluene sulphonanilide was fed to 6 male and 16 female ring-necked pheasants (Phasianus colchicus). Birds
receiving the mercury-treated ration were separated from the opposite sex. After receiving the mercury-treated ration for 0, 2, 4, 8, or 16 days, previously selected pheasants were removed
from the pens and placed in another pen with pheasants of opposite sex not fed the mercury-treated ration. Eight groups of two males and four females were studied. Effects of the mercury-treated ration on production, weight, fertility, hatchability, and shell thickness of eggs laid by ring-necked pheasants, and sex ratios, post-hatch survival, and weight of chicks hatched from those eggs were evaluated. Production of eggs by the group in which only females received the mercury-treated ration 4 days and by the group in which only males received the treated ration 8 days was greater than by the control group. However, egg production was less than controls among the groups in which females received the treated ration 2, 8, and 16 days and in which males were fed the treated ration 4 and 16 days. Mean weights of eggs of all groups were significantly greater (P<0.01) than the mean weight of eggs of the control group. Fertility of eggs appeared to be unaffected and was 90.8 percent or greater in all groups. Hatchability of fertile eggs of all groups in which females were fed the mercury-treated diet was greater than among all groups in which males received the treated ration, or in the control group. Mean shell thickness of eggs was significantly greater (P<0.01) than controls among females fed the treated ration 4 and 8 days and significantly less (P<0.01) than controls among females fed the treated ration 16 days. There were no significant differences (P>0.05) between mean eggshell thickness of the control
group and all groups in which males received the treated ration. Sex ratios and post-hatch survival of chicks hatched from eggs of all groups apparently were not affected. The mean weight of chicks hatched from eggs of controls was less than mean weights of chicks hatched from eggs of all other groups. Effects of ethyl mercury on some parameters of reproduction in ring-necked pheasants were inconsistent. Based on this study, whether or not organic mercury compounds in diets of wild pheasants would affect reproduction sufficiently to change population levels of the species significantly remains problematical.