Thursday, August 21, 2014

Allie's project: What did she say?

 My name is Allie Burnett and I am an undergraduate at Michigan State University in Zoology. This summer I returned to KBS to work on another project related to Cara's research.

When I first started studying birds, I found the varying types of songs and responses to these songs interesting. I wanted to know what these birds were "saying" to each other and what determined which type of song was used. The discovery of female song in our House Wren population intensified this curiosity, especially since female song is unexpected in temperate zone House Wrens. The huge difference in responses to various female songs supported the idea that each song was communicating something specific to the recipient. Perhaps these females, who responded most aggressively to other female song, were using songs to communicate and compete with rival females. One of the most important things to communicate to a rival female is something that will influence the outcome of a fight, such as physical condition. We knew from prior experiments that specific song characteristics elicited greater aggressive responses; did these song characteristics also correlate with physical characteristics of the female singing them? In order to find this out, we spent the summer recording songs and gathering physical measurements from each female. After hours of song analysis, we found that female condition does influence female song. Not only did females of higher condition sing a greater variety of songs, but they also sang more notes per second and a higher percentage of a syllable named "R." These characteristics were the same ones that elicited high aggressive responses. These results lead me to further question why females of higher condition sing differently. It is possible these females can afford to sing songs that elicit more aggressive responses in order to obtain resources. Alternatively, maybe these song characteristics elicit such aggressive responses because they are more likely to be sung by a high condition female, and therefore a much larger threat. Only more research will be able to tease apart the secrets of female song.

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