Date of Award
Master of Science (MS)
The functions most commonly ascribed to bird song are mate attraction and territory defense. These are combined into the "dual function" hypothesis. I tested this hypothesis to determine if these are the functions of song in chipping sparrows (Spizella passerina).
I performed a series of neighbor/stranger song playbacks to test the territory defense portion of the "dual function" hypothesis. If song has a territorial function, songs of different individuals might be recognized by territory owners and might elicit different levels of response. However, territorial male chipping sparrows did not respond differently to neighbor and stranger song playbacks either early in the breeding cycle (n=!8) or after the onset of incubation (n=10). There was also no decrease in Urn ’cvel of response between the early and late playbacks. These experiments did not elicit the pattern of results predicted on the basis that song has a territorial function.
I also attempted to determine sorig function by quantifying song output relative to reproductive status. High levels of singing were observed only in unmated males (n=27). Singing activity effectively ceased after pairing. This pattern of singing rejects the "dual function" hypothesis and supports an alternative that song has only a mate attraction function.
Information from a limited number of studies has been used to develop assumptions about the relationship of song function and complexity. These assumptions relate the function of mate attraction to song complexity, while territorial song is expected to be short, simple, and stereotyped. However, chipping sparrow song appears to function solely in mate attraction, while its physical features resemble what could be considered typical territorial song. Possible relationships between the physical features and function of chipping sparrow song are discussed.
Albrecht, Daniel J., "Function of Song in Chipping Sparrows (Spizella passerina)" (1991). Theses and Dissertations. 1013.