Virtually any exercise in ecology will require some knowledge of the techniques for carrying out a census of population numbers. This practical text outlines clearly, with worked examples, the main techniques used by field ecologists to enumerate plants and animals. Each taxonomic group is treated separately, with detailed descriptions of appropriate census methods; their advantages, disadvantages and biases. Techniques for measuring a wide range of environmental variables are also included. The final chapter lists the 20 most common censusing sins. Concise yet comprehensive, this book provides a unique overview of the most important methods for those working on field studies in population and behavioural ecology and conservation biology at all levels, from the beginner to the practising professional.