Effects of Dieldrin in Penned Pheasants through the Third Generation

In 1968 and 1969, single capsules containing lactose or lactose and dieldrin were given weekly to pheasants (Phasianus colchicus); hens received 0, 6, or 10 mg and cocks received 0, 4, or 6 mg. Offspring of these birds were bred in 1969 and 1970, and offspring of second generation birds were bred in 1970 and 1971. Direct mortality occurred in breeders at all levels of dieldrin administered, but weights of breeders were not affected by dieldrin. Egg production, fertility, hatchability, viability of chicks at hatching, and weights of chicks from 4 to 6 weeks of age exhibited no relationship to treatment, and were erratic among groups and years. Survival of chicks to 4, 5, or 6 weeks of age was affected (P < 0.01) by dieldrin administered to hen parents; offspring of second- and third-generation hens did not differ in survival in relation to treatment (P > 0.05). Offspring of parents given dieldrin chose the deep side of a visual cliff more often than control chicks (P < 0.05), as did their progeny in the second and third generations. Offspring of parents given dieldrin were more easily caught by hand (P < 0.01); this effect was also found in the second and third generation. Behavior, both on the visual cliff and in response to hand catching, was generally most affected where both parents or ancestors had been given dieldrin, and less, but still affected, where either parent or ancestor had been given dieldrin. A genetic mechanism may have been involved in effecting aberrant behavior patterns.