Complex Organization of the Warbling Song in the European Starling Sturnus Vulgaris

Abstract

Male starlings sing two very different categories of song: whistles and warbles. The present study describes the structure and the organization of warbling song in individuals from varied geographical origins. In all cases, warbling is shown to be an extremely complex song in which there is much contrast: very different notes follow each other and are even superimposed. Higher levels of organizations are present: notes are grouped in repeating units, the motifs, each of which is sung in bouts of 1 to 12 repetitions, and finally these bouts show a clear sequential organization. A certain amount of variability occurs at each of these levels: slight variations are seen from one rendition of a given motif to the next; the number of repetitions of each motif varies from one song sequence to another and the sequential organization of bouts seems to be able to vary seasonally. All these characteristics were found in all individuals. Nevertheless, warbling appears to be an essentially individual song. Beyond two or three species-specific motifs, the others in the repertoire are individually characteristic. The beginnings and endings of the songs are clearly defined commencing usually with an individual motif whilst ending with a species-specific motif. We observed marked differences between individuals in repertoire size, extending from about 20 to more than 35 different motifs. This is the only measure of the repertoire that we have been able to define for this continuous song.