Lead and behavioral development: effects of varying dosage and schedule on survival and performance of young common terns (Sterna hirundo).

Exposure to lead early in life is known to affect behavioral development. Young common terns (Sterna hirundo) were injected with lead nitrate solution (0.2-1.2 mg/g) or sterile saline to examine the dose-response curve for behavioral effects. Exposed chicks received a dose of lead on d 3 or on d 3 and 7. Behavioral tests 2 d after each injection included visual cliff performance, locomotion, and righting response. Survival depended not only on dose but also on whether chicks received one or two injections. Despite the narrow range of doses, behavioral differences were noted for all measures as a function of dose. The initial lead dose affected behavior more than the second dose, despite the fact that birds receiving a divided dose were more likely to die.