Department or Program



Bird song is an animal signal that serves as the primary method of mate attraction in most songbirds, a group that accounts for the majority of bird species worldwide. While it has been established that there can be a wide range in song quality within a species, and that high-quality vocal performance tends to attract more mates, less is known about the effects of differing vocal performance on the behavior of other competing males. It also has not been established whether individual birds can alter their own vocal performance quality in response to different situations. In some birds that sing a trilled vocalization, it is possible to quantitatively define the vocal skill required to produce a given song. In this Honors Thesis, I explore these issues in the chipping sparrow (Spizella passerina), whose trilled vocalization facilitates measurement of the vocal skill required to produce a given song. I tested three competing hypotheses concerning the vocal performance of this species: (1) that individuals modulate their song quality in different competitive contexts, (2) that individuals differ from one another in their vocal performance and are unable to modulate their vocal performance, and (3) that individuals are neither different from one another nor modulate their vocal performance. Over the course of a single breeding season, chipping sparrows were captured, color-banded, and recorded as they sang spontaneously. In a playback experiment simulating territorial intrusions by both high- and low-quality males, tested birds did not modulate any aspect of their vocal performance outside of singing more often while a simulated intruder was also singing (p=0.223). In all contexts, the largest source of variation in song was attributable to inherent differences between individuals (p

Level of Access

Open Access

First Advisor

Dearborn, Donald

Date of Graduation

Spring 5-2015

Degree Name

Bachelor of Science

Number of Pages


Open Access

Available to all.