By comparison with other icterids, the bobolink (Dolichonyx oryzivorus) sings an unusually long and complex song. The songs of four male bobolinks were analysed in terms of units at four different levels of analysis: the figure, the figure-sequence, the song-pattern, and the song. The different levels of analysis show different degrees of stereotypy and variation. Individual males in the study area differed in the frequency of use of the different song-patterns and in the way they assembled them into songs. Immediate repetition of song patterns within a song was unusual. Songs sung from fixed perches were shorter than songs sung in flight. The results suggest that the length of bobolink song is in part a consequence of its use of the song as a part of an elaborate flight display, and that the unit we called the “song-pattern” was closest to the unit designated “song” in most other species.
Thompson, Nicholas S., "Levels of Organization in the Song of the Bobolink (Icteridae: Dolichonyginae)" (1983). Faculty Works. 56.