JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. British Ecological Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Applied Ecology. Summary 1. Data on fecundity and mortality obtained from wild rabbit Oryctolagus cuniculus populations in England were used in Leslie Matrix population projections to examine rate of population growth and the effect of time of control on population growth. 2. The population growth rate was shown to be slightly greater than unity in an average year. 3. Control policies which remove more adults than juveniles are best performed at the end of December and policies which remove more juveniles than adults are best performed in mid-June. 4. The limitations of the model used are discussed, as are limitations in the data. It was concluded that more information was required on natural mortality rates, especially fot the first few weeks of life.