Song "Dialects" in Three Populations of White-Crowned Sparrows

Abstract

The phenomenon of dialect variation in bird song, appearing as a consistent difference in the predominant song type between one population and another of the same species, has a special interest for biologists, serving as a focus for attention in discussion of such diverse topics as speciation (for example, Huxley, 1942; Mayr, 1942), learning (Thorpe, 1954, 1958) and the mechanisms of social communication (Marler, 1959). The White-crowned Sparrow (Zonotrichia leucophrys) affords one of the best known cases of such dialect variation among North American birds, and it has been commented upon by many who have observed this species (Blanchard, 1941; Peterson, 1941). Before the ontogenetic basis of such local song variation can be assessed and before its evolutionary significance can be satisfactorily determined, careful descriptions of the nature and extent of the variation are required. This paper seeks to provide some of this necessary information by describing song variation in the individual and in a population, both at one time and from year to year, and also by comparing songs in three populations, two adjacent and one distant.