Comparative Dietary Toxicities of Pesticides to Birds

This report presents measurements of the lethal dietary toxicity of 89 pesticidal chemicals to young bowhites, Japanese quail, ring-necked pheasants, and mallards. Toxicity is expressed as the median lethal concentration (LC 50) of active chemical in a 5-day ad libitum diet. LC 50's and associated statistics are derived by methods of probit analysis. Endrin consistently was the most toxic chemical while aldrin and dieldrin were among the six most toxic chemicals of those tested on all species. In general, organophosphates were less toxic than aldrin or dieldrin and herbicides were of a low order of toxicity. There were obvious inconsistencies in the relative sensitivity of the four species to various chemicals.