A proxy of social mate choice in prairie warblers is correlated with consistent, rapid, low-pitched singing

Abstract

In songbirds, female mate choice may be influ- enced by how well a male performs his songs. Performing songs well may be especially difficult if it requires maximiz- ingmultipleaspectsofperformancesimultaneously.Wethere- fore hypothesized that, in a population of prairie warblers, the males most attractive to females would be those with superior performance in more than one facet of singing. We tested this prediction by comparing different aspects of song perfor- mance, as well as different combinations of these aspects, to determine which were the best predictors of first-egg date, which we took to be a proxy for social mate choice. We found thatfirst-egg datewasbestpredicted bya combination ofsong performance traits that included consistent performance, rapid rate, and low pitch. Female preference for males capable of physically challenging song performance may have contribut- ed to the evolution of acoustically complex vocalizations in oscine songbirds, because if complex sounds are more difficult to perform, they may be favored by selection for signal reliability.