The theory of natural selection suggests that individuals should possess the ability to evaluate the suitability of mates and make beneficial choices. A beneficial choice leads to maximum production of breeding offspring whereas a poor choice leads to little or no reproductive success. In many species, it is the female sex that makes the choice of a mate; males typically compete among themselves for control of resources important to reproduction and attempt to attract females to their domain. Despite its general importance, the biological bases of mate choice are poorly understood for most animals. In the current research, behavioral and physical characteristics of males and how these traits function in the process of mate choice by females will be studied. Two species of birds have been selected because they are easy to observe in nature, their communication behavior is relatively simple, males learn their vocal "language" much like humans learn speech, and birds can be taken into the laboratory for more controlled experiments to reveal the properties of the communication system. All these reasons make birds one of the most widely used research animals for uncovering the biological principles of social behavior of animals, particularly in the area of communication. Questions that will be addressed include: 1) How do males and females communicate, both visually and vocally, in the context of mate choice and reproduction, 2) do females discriminate among potential mates by their vocal characteristics, their physical characteristics, or both, and 3) what properties of the male are communicated by his vocalizations or by his physical traits and behavior. By field studies in natural populations, and by laboratory experiments with captive males and females, the current research allows a powerful approach to answering these questions.
