The Social Behaviour of the Dunnock Prunella Modularis

Summary Observations were carried out on a colour‐ringed population of Dunnocks. During the winter, regular feeding groups formed at feeding sites, stable in composition, space and time. Dominance hierarchies formed and were weight related. Males were significantly heavier than females. The mean size of winter home‐ranges was not significantly different from the mean size of breeding territories. Three categories of breeding territory were established: solitary males, male‐female pairs and pairs plus a male helper. There was one case of a bigamous male plus a helper. Pairs plus a helper had significantly larger territories than pairs alone; however, pairs raised significantly more fledglings. Five pairs produced a total of 23 fledglings, whereas four groups (pairs plus a helper) only produced seven fledglings.