Capture-Recapture Analysis

This paper presents a new method for the analysis of capture-recapture data. Previous methods have employed deterministic or partially stochastic models of the population under study; the new method not only provides a fully stochastic model, but it also allows death-rates to depend upon both current time and the health and age of the separate individuals. The numerical analysis associated with the method is, however, heavy, and can only be recommended when one wants to extract the maximum amount of information from data which have required much effort or time to collect. The method is illustrated by an estimation of the death-rate of Alpine Swifts (Apus melba) in the wild state. Some thirty years having been spent in collecting these data, it does not seem disproportionate to have spent several months in computing the results. The larger part of this calculation was done on ordinary desk calculators. Some unusual problems in maximum-likelihood estimation are discussed.