Written by international experts from many disciplines, this multi-volume treatise is a comprehensive survey of the established data and principles of avian biology. The volumes thoroughly review knowledge of the 8600 living species of birds-knowledge resulting from advances in instrumentation and technology and improved transportation facilities that permit more detailed, far-ranging field studies than ever before. The emphasis is on the significance of avian biological research to such areas of biology as ethology, ecology, population biology, evolutionary biology, and physiological ecology.