Silent Spring Revisited: A 21st-Century Look at the Effect of Pesticides on Wildlife

Abstract

Published in 1962, Rachel Carson's Silent Spring is considered a cornerstone of modern environmentalism. Carson documented disruptions in free-ranging avian populations related to the use of pesticides. Unfortunately, the damage done by these chemicals continues today. Recent, sometimes massive, die-offs have been reported in various species because of the use of pesticides. Exposure to sublethal doses of pesticides may lead to profound reductions in reproductive success associated with embryotoxicity, eggshell thinning, and even a decrease in reproductive behavior. Since the use of organochlorine pesticides was banned in North America in the 1970s, the reproductivity of many species such as the bald eagle (Haliaeetus leucocephalus) has improved dramatically. However, some migratory species continue to demonstrate organochlorine residues in their eggs and low reproductive rates. The reasons for these findings are not completely understood, but they may be related to the persistence of organochlorines in the environment in North America as well as the continued use of organochlorines in Latin America. As veterinarians, we must continue to be vigilant in our diagnosis, as well as in speaking out for reducing pesticide use. Pesticide toxicosis should always be considered in any dead or debilitated avian carnivore or piscivore, even when another problem is apparent.