Pesticide dynamics in robins nesting in contaminated and uncontaminated forests in northern Maine

Abstract

The pesticide dynamics in robin (Turdus migratorius) populations nesting in DDT-contaminated and uncontaminated forests in northern Maine were investigated between 1966 and 1973. About 25% of a female's pesticide load passed into each clutch of eggs. Adults nesting in uncontaminated areas lost about 87% of their pesticide load by August, and there was a significant decrease in pesticide levels from eggs to fledglings. Adults nesting in contaminated areas exhibited no loss of pesticide during the reproductive season and residue levels increased from eggs to fledglings. No eggshell thinning or egg mortality was noted.