Population decline and management plan for the peregrine falcon

Abstract

Scope of Study: This library report summarizes the major works that have been carried out in the study of the peregrine falcon (Falco peregrinus) and outlines several management steps that may be effective in reversing the current decline in population levels that are presently occurring world wide.

Findings and Conclusions: The peregrine falcon has experienced a world wide population crash during the years 1950 to 1965. The status of the present day populations is not widely agreed upon except that at least one and possibly two of the 12 subspecies is now extinct. Chlorinated hydrocarbons have effected an imbalance of the sex hormone endocrine system of these birds. This imbalance has led to thin eggshells, reduced fertility, and generally low reproductive rates, which were less than mortality rates and a population crash was the result. Management of the remaining peregrine populations can be in the form of absolute protection, purging adults systems free of pesticides, holding juveniles in captivity until two years of age and then releasing them, and by establishing captive breeding stocks to produce young which would be released to the wild to augment natural reproduction. Introduction of permanent wild populations by the use of alternative subspecies in areas where total extinction of the population has occurred may be possible after pesticides are eliminated from the world ecosystem and if habitat remains to support them.