Variance estimate for the Allen activity index

Abstract

The Allen activity index, originally developed for monitoring dingo populations, is statistically described as a mixed linear model, from which a variance formula for the index is derived. The resulting formula requires input of variance component estimates, the estimation of which is accomplished using restricted maximum-likelihood estimation. An example is used to demonstrate the calculation of the variance components and their use in the variance formula. Application of the variance formula substantially enhances the quantitative practicality of this useful index of wildlife populations.