The Development of Social Behavior in Birds

Abstract

The purpose of this brief survey is to illustrate by means of selected examples the manner of operation of factors that control development of social bonds in birds. Socialization of the young individual will be considered first, followed by a discussion of sexual and parental bonds. The general problem of gregariousness and bird flocking is considered by J. T. Emlen, Jr., in another paper (Auk, 69: 160-170, 1952) in this symposium on social behavior in birds. Each of the different aspects of social development can be analyzed into genetic, physiological, and social levels of organization, and into the interactions between these levels. However, our knowledge of the various factors of social development is still very uneven, and no really general treatment is yet possible. In an attempt at a rounded treatment some unpublished notes of my own will be included. Much of our more analytical knowledge of the biology of reproduction in birds has been derived, for obvious reasons, from studies on the domestic fowl and the domestic pigeon. At the least, these studies may help to provide guideposts in our search for understanding of wild birds existing in a state of nature, although some wide variations between species may be expected to occur. In the writer's opinion, parallel studies on the behavior of unconfined and undomesticated species of birds have generally shown many more similarities than differences compared to studies on confined or domesticated birds. SOCIALIZATION OF THt{ •rOUNG BIRD Social development is one aspect of the development of behavior in general, and as such involves behavior patterns that are laid down prior to hatching; and these in turn depend on the development of structures more directly under genetic control. However, most of the major trends in socialization belong to the post-hatching reactive phase in which activity is generally governed or directed by external 127