An assessment based on residues in owls of environmental contamination arising from the use of mercury compounds in British agriculture

Abstract

Tawny Owls ( Strix aluco) and Barn Owls ( Tyto alba) killed by traffic have been collected as part of a pollution monitoring programme. Specimens suitable for monitoring purposes have been analysed for total mercury residue by a flameless atomic absorption technique. 109 Tawny Owls and 87 Barn Owls collected in the period 1967–1973 have been analysed. The mean total mercury residue in the pectoral muscle of the Tawny Owl and Barn Owl was 0.25 ± 0.02 and 0.18 ± 0.02 ppm respectively. A constant relationship was found between the mercury residues in the pectoral muscle, liver, heart, kidney and brain of specimens. The results are discussed in relation to the published results of experimental feeding studies and surveys of mercury residues in wildlife. The study indicates that the use of mercurial seed-dressings in Britain has not led to significant contamination of the Tawny Owl and Barn Owl.