Relative importance of male and territory quality in pairing success of male rock ptarmigan (Lagopus mutus)

We studied pairing success in male rock ptarmigan (Lagopus mutus) in northe rn Alaska to learn whether males obtaining more females possessed phenotypi c traits that influenced female choice directly, whether these traits permi tted males to obtain territories favored by females, or whether both proces ses occurred. The number of females per male varied from zero to three. Sev eral male and territory traits were significantly correlated with number of females per male. We used multiple regression to obtain a single measure o f male quality and a single measure of territory quality. These measures of male and territory quality correlated with each other and with male pairin g success. We used path analysis to separate direct effects of male quality on pairing success from indirect effects due to high-quality males obtaini ng high-quality territories. Both direct and indirect pathways had signific ant effects on pairing success, and direct and indirect effects of male tra its on pairing success were about equal. This study illustrates an analytic al approach for estimating the relative importance of direct and indirect c ausal relationships in natural systems.