LONG-TERM PERSISTENCE OF A CULTURALLY TRANSMITTED VOCALIZATION OF THE BLACK-CAPPED CHICKADEE

The gargle vocalization of the black-capped chickadee, Parus atricapillus, was recorded at the same site over a 19-year period. This vocalization consists of an array of different note types that are combined to generate various call types. Each male has a large repertoire used in agonistic encounters, and many variants are shared with other members of the population. The vocalization was analysed at several different levels: note types and various lengths of note-type sequences including the whole call. Remarkable stability was shown for all levels, and the main changes observed were minor ones of relative frequency of occurrence. Reasons for stability may include persistence of note types in linkage groups that could be transmitted as units (memes) and other rules governing ordering of note types in the can (syntax). Also, natural selection may impose some constraints on the process of cultural transmission. We compare our findings with those of the few available long-term studies of bird song. Chickadee gargles are transmitted very precisely compared to other vocalizations that have been previously studied. (C) 1995 The Association for the Study of Animal Behaviour