The impact of hierarchy in birds on various parameters of fitness

Many birds species live in hierarchically structured flocks. The aim of this thesis is determine how the hierarchy is organized to what and extent the hierarchy influence the fitness of dominant individuals. It is focused on the well explored effects of instrinsic factors such as age, body size and sex as well as on the influence of personality that has been examined in recent years. Advantages of hierarchy can be demonstrated by long-term studies, that observe the stability of the hierarchy. Apparently, dominant individuals are able to inform others about their social status and fighting ability through the signal status, which is an honest signal of overall qualities this individuals. Dominant individuals have significantly higher reproductive success, but the mechanisms may differ and reproductive success can achieved through indirect correlations of fitness such as priority food access or better territory. But there are some exceptions where dominant individuals do not profit from their social status. Key words: hierarchy, dominance, social systems, fitness, reproductive succes