| Summary: | The dominance hierarchy and the effect of the social status on survival was studied in 18 winter flocks of the Willow Tit near Oulu northern Finland in 1986-87. The flocks were small and stable groups that usually consisted of an adult pair and apair of yearlings, which were never descendants of their older group companions . In general, males were ranked higher than the females. Within sex groups, adults dominated yearlings . The birds with long tarsi dominated individuals with shorter ones . Wing length was not correlated with social status . The size variables had no effect on rank order in group members of the same age and sex. The dominant individuals had higher survival rate than the subordinates . In juvenile birds the survival rate of high-ranking individuals was higher in both sexes. Reasons for these differences, and explanations for the existence of subordination as a strategy, are discussed. Subordinates, although having a higher mortality rate, are supposed to have even higher one if they adopt a solitary way of life. Several benefits attached to living in groups evidently outweigh the costs caused by dominant individuals .
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