Collecting Population Data

Abstract

Definition of the population (the individuals of a species present in a defined area at a certain time) is central to most disease investigations and is also one of the most difficult aspects of any study of wild animals. There are a great variety of methods for describing a population, but when dealing with disease these usually involve elaboration of a few basic questions:

• who is present?

• who is at risk?

• who is affected?

• what effect is disease having on the population?

“Crudely put, observers go afield to seek wildlife and return to tell the statistician how many they have found. It is then the statistician’s task to determine how many animals they did NOT find” (Ramsey et al., 1988)