New Zealand Journal of Ecology (1980) 3: 117- 124

Effects on birds of spraying DDT and DDD in orchards

Research Article
P. R. Wilson  
  1. Ecology Division, DSIR, Nelson, New Zealand

The quantities of organochlorine insecticide residues in mynas (Acridotheres tristis L.) and especially in their eggs and nestlings reflected the concentrations of these pesticides in the soil of the birds' territories. Nearly all residues were derived from con- tamimated invertebrates, not fruit. Samples of soil, eggs and nestlings from areas adjacent to sprayed orchards contained little pesticide-no more than was found in samples collected several kilometres from orchards. Although some adult starlings (Sturnus vulgaris), blackbirds (Turdus merula) and song thrushes (Turdus philomelos) died in tremors typical of organochlorine poisoning, no mynas were seen with these symptoms; earthworms, which readily accumulate DDT, DDD and DDE from the soil, are eaten less by mynas than by these other species.