POSSIBLE MORPHOLOGICAL ADVANTAGES FOR TOLERATING HIGH TEMPERATURE AND HUMIDITY IN A SUBTROPICAL PASSERINE (PEUCAEA AESTIVALIS)

Animals face both natural and sexual selection pressures, and at times, these pressures conflict with one another. This results in a tradeoff between sexual and natural selection. In my thesis, I examine aspects of Bachman’s sparrows’ behavior and morphology in relation to weather conditions in light of these two conflicting pressures.
Large bill size is selected for by the natural selection pressures of thermoregulation. Smaller bills are selected for by the sexual selection pressures of song quality. Both thermoregulation and song are important behaviors/processes that have fitness implications. By looking at bill size in relation to thermoregulatory ability and song quality I examined the tradeoff between these two selection pressures acting on the bill of Bachman’s sparrows