Professor Cockburn has an international reputation for his contributions to behavioural ecology and evolutionary theory. He uses Australian species to examine important theoretical questions on how selection operates and how individuals maximise their fitness. He showed the importance of post-fire plant succession for survival of the heath mouse. He used Antechinus to provide unique tests of sex allocation, litter size and sex-biased dispersal. Using genetic probes, he has demonstrated the role of helpers, paternity, cuckoldry, mate selection and life time strategies of both sexes in cooperatively breeding choughs and fairy wrens. His work provides a novel integration of ecology and evolutionary theory.