Lawrence J. Blus Richard M. Prouty Charles J. Henny 1982 <p>A single egg was collected at 62 nests of 10 seabird species from Oregon in 1979. The eggs were analyzed for organochlorine contaminants; contemporary shell thickness was compared with eggshells collected during earlier time periods. Concentrations of DDE and PCB's in 1979 were generally low with the most contaminated species being the Double-crested Cormorant (<i>Phalacrocorax auritus</i>), Leach's Storm Petrel (<i>Oceanodroma leucorhoa</i>), and Forktailed Storm Petrel (<i>O. furcata</i>). Limited eggshell data provide evidence that shell thinning was more severe along the Oregon coast in the 1950's than in 1979. With the possible exception of the Fork-tailed Storm Petrel, the residues in 1979 posed no known threat to the welfare of the species.</p> application/pdf 10.2307/3535474 en Society for Northwestern Vertebrate Biology Organochlorine residues and shell thinning in Oregon seabird eggs article