An Overview of Territorial Displays in Birds:

Five Factors to Understanding Evolutionary Origins and Current Mechanisms

Michael Pennock- Davidson College-BIO 323: Animal Behavior

(courtesy of Yummifruitbat, permission through Creative Commons Attribution ShareAlike 2.5 license)

All bird species employ various territorial displays that are the evolutionary product of responding to environmental pressures and competition among individuals. There are many factors that contribute to the uniqueness of a bird’s particular display, and there are several main points of interest in examining the development of a particular behavior. The first factor is the cost/ benefit ratio of the behavior, considered in such a way that the bird reduces the metabolic and territorial costs of its behavior and enhances the benefits. The second factor is the evolution of acoustic behavior in birds, by far the richest area in bird territoriality, which is an important tool manipulated in order to deter potential invaders, to assess resource-holding potential (RHP), and to avoid harmful combat. The third factor in territorial displays is the social learning involved in acquiring the skills necessary to defend a territory, which is comparable to how humans learn speech. The fourth factor in bird territoriality is the existence of physiological indicators of fitness, whether present in acoustic calling or plumage coloration, that are stable signals to other birds of potential threat level. The fifth factor is the ecological and geographic variation in territorial behavior, which reveals how territorial behavior has a cultural aspect, and allows all of the previous factors to be observed in action at once.

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