Black duck (Anas rubripes) eggs were collected in 1971 from the Northeastern United States and Canada. All 61 eggs analyzed contained DDE residues; the mean DDE residues for States and Provinces ranged from 0.09 to 5.94 ppm on a wet-weight basis, with.mean concentrations exceeding 1.0 ppm in eggs from Maine, New York, New Jersey, and Delaware. The highest DDE concentration, 14.0 ppm, was in an egg from Delaware. DDD and DDT residues averaged