Habitat effects on behavior in a wide-spread territorial song bird, Melospiza melodia

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Scales, Jennifer
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In territorial systems where quality varies across an area the behavior of individuals is likely to be affected. Territorial aggression is likely linked to territory quality while behaviors like boldness may be linked to novel experiences or disturbance. The goal of this study is twofold: First, to determine whether individual male’s aggression and boldness responses correlate to territory quality (established by historical, 2000-2007, fledging success and clutch sizes) in a natural setting; Second, assess whether territorial individuals in areas disturbed by humans show a difference in behaviors when compared to their more naturally located counterparts. For both questions song playback was used to assay male territorial aggression and flight-initiation-distance was used to assay male boldness. It was found that male song sparrow aggression correlated with historical clutch size but not historical nest success; neither historical clutch size nor nest success correlated with boldness. Results suggest that either more aggressive males are better able to obtain and defend higher quality territories or that males modulate their aggressive behavior according to territory quality. For the second question, a comparison was conducted between aggression and boldness responses in the natural population and males found in the nearby towns of Linesville and Conneaut Lake, PA. Males on human disturbed territories are significantly more aggressive and bolder than males found in natural settings, suggesting more aggressive and/or bolder males are better able to cope with human related stresses or that human disturbance causes a change in male behaviors. Alternatively, given that aggression is correlated with territory quality it may be that human disturbed territories are of a higher quality than the natural territories.
Song Sparrow -- Behavior