This project seeks to understand the ecological basis of social behavior by focusing on a species of bird common in the Western United States with an extremely unusual social organization, the Acorn Woodpecker. This species lives in family groups of up to 15 individuals of both sexes and all ages; all birds in a group share in defending the territory and raising young. The study population consists of about 120 birds, the majority of which are individually color-marked, and has been going on continuously since 1971. Thus, the project allows the unique opportunity to obtain basic data on long-term demographic consequences of group living. It also allows an investigation of some of the specific adaptations to group living shown by this species as well as the advantages and disadvantages of their unusual social organization. In particular, Dr. Koenig will be exploring the consequences of group living using time-activity budgets, the mechanisms of brood reduction, and the role of vocal behavior in group integration. Data acquired by the basic research being done as part of this project will provide new information toward the understanding of the evolution of social behavior. In particular, it will uncover more about both the short-term and long-term consequences of group living and of altruistic behaviors, many of which are shown by this species.
