Chlorinated Hydrocarbon Residues in Peregrines Their Prey Species from Northern Canada

This paper reports upon the levels of chlorinated hydrocarbon pesticide residues in Peregrine Falcons ( F&o peregrinus ) , Peregrine eggs, and in the prey species of Peregrines from western Canada, and compares these findings with those from other regions, particularly Great Britain. Also included are data on the reproductive success of the pairs we encountered. This project was conceived when it became clear at the International Conference on the Biology of the Peregrine Falcon held at Madison, Wisconsin, in September 1965 that organoclhlorine residues are very possibly responsible ‘ for the drastic decline of Peregrines in Europe, Great Britain, and the United States. #Several scholars in England (Cramp 1963; Ratcliffe 1963; Ratcliffe 1965; Jefferies and Prestt 1966) have attempted to correlate the reduction of the Peregrine with the presence of pesticide residues, but no work on the subject in North America has been published.