Winter social behaviour of dark-eyed juncos: Communication,social organization,and ecological implications

This paper reports on winter social behaviour in free-living and captive flocks of dark-eyed juncos (Junco hyemalis). Visual and vocal signals used by flocked juncos are analysed structurally and functionally. An examination is made of the frequency and form of agonistic behaviour in several social and environmental contexts in an attempt to provide insight into the relationship between junco communication and social organization. A system of classification of signals, based upon the meaning of cues to the signaller, is proposed. Evidence is given to suggest that the behaviour of subordinate, rather than of dominant, individuals controls the operation of the social system in junco flocks. Some ecological implications of junco social behaviour are discussed.