Agonistic Behavior and Territory in the American Redstart

TH purpose of this study is to describe the agonistic behavior of the American Redstart, Setophaga ruticilla, and to interpret this behavior from an ethological standpoint, i.e., in terms of its causation, function, and derivation. In addition, individual distance and territory are discussed. METHODS A few essential terms are reviewed. Agonistic behavior is concerned with attack and escape. Individual distance "is an area around a bird, which moves with it, has no topographical reference, and into which no other individual is allowed to come" (Conder, 1949). Displays are defined by Moynihan ( 1955) as "those peculiarly standardized and often exaggerated performances, including all vocalizations and many movements and postures, which have become specialized and modified as social signals or releasers." Blest (1961) describes ritualization as "the evolutionary process responsible for the existence of inter-and intra-specific signalling movements." Intention movements are the "incomplete and low intensity movements, so called by Heinroth because they reveal what the animal is 'intending to do'..." (Marler, 1956). Tendency is used here in the sense of Hinde given by Marler (1956) as the "readiness to. show a particular