Organochlorine insecticide residues in wild birds in Britain

Organochlorine insecticide residues in a wide range of wild birds and their eggs from all over Britain have been determined by gas‐liquid chromatography and paper chromatography. Higher residues were found in predatory species than in omnivorous or herbivorous species. To illustrate the residue pattern in predatory species analytical data for specimens of the Heron, Kestrel and Sparrow‐Hawk have been summarised. The source of the residues and their possible effects upon birds are discussed.