Avian Biology, Volume VI is a compendium of papers that deals with selected aspects of avian biology. One paper discusses the avian mating behavior and covers topics such as monogamy, polygyny, male incubation, and female emancipation; these papers also list a table of the species of birds in which polyandry has been observed. Another paper examines bird migration in relation to the mechanism and development of migration with emphasis on the evolution and function (ultimate causation) of migration. Another paper discusses the advantages of one form of social organization of birds during the no