DISSERTATION RESEARCH: Function of Multiple Signals in Avian Vocal Communication

Duke University, Durham NC

Investigators

Abstract

The function of multiple signals in avian vocal communication Stephen Nowicki Martin D. Beebee The puzzling occurrence of highly conspicuous traits in the males of many species of animals is thought to be explained by the fact that these traits act as signals to potential mates, indicating something about phenotypic or genotypic quality. This apparent resolution, however, does not easily explain cases in which individuals exhibit more than one conspicuous trait. For example, many songbirds use a combination of bright coloration and complex vocal displays in courtship, or multiple kinds of courtship vocalizations. If an individual trait can act as an indicator of male quality, what is the added function, if any, of possessing two or more such traits? The goal of this project is to study the function of multiple vocal traits in the yellow warbler (Dendroica petechia), and test a hypothesis for how different traits of an individual might function as signals. As with several groups of North American and European songbirds, yellow warblers have two distinct modes of singing: one relatively simple and one more complex. Results from previous work suggest that these singing modes are specialized for communicating different messages to males and females. This hypothesis will be evaluated using a combination of field and laboratory studies to examine three important aspects of signal function: how the singing modes are used by males, what kinds of information the singing modes convey, and how males and females respond to the different singing modes.