METABOLIC COSTS OF DOMINANCE IN DIPPERS, CINCLUS-CINCLUS

The status of temporarily captive dippers was assessed in a laboratory arena with dyads competing for access to a perch. In this way dominance scores and a dominance ranking were obtained for each individual, which were largely independent of site-specific factors. Dominance scores were compared with basal metabolic rates (BMR) obtained by prior overnight measurement on the same individuals: dominant males had a higher BMR. Neither plumage colour nor body size measures (with one exception) were related to mass-specific metabolism. The energy cost of dominance was relatively small, however, when compared with daily energy expenditure of free-living dippers. It is concluded that the obligate metabolic costs of dominant behaviour were unlikely to have a significant effect on energy balance or survival.