![]() ![]() Robins are as normal but there’s been a shortage of dunnocks foraging on the grass below the feeders. The usual garden residents such as the tits - great, blue and coal - are in the same numbers as in other winters but there are no long-tailed tits yet. Thus, sparrow flocks were not characterized by association of relatives, nevertheless the presence of some close kin may provide opportunity for kin-biased behaviours to evolve.I’m delighted by a healthy number of greenfinches but there are less chaffinches than usual. Finally, relatedness among members of different flocks was unrelated to the distance between their flocks. between-flock relatedness, and birds had similar proportions of close kin within and outside their home flock. Furthermore, there was no difference between within-flock vs. Pairwise association between individuals was not significantly related to their genetic relatedness. We found that most birds were unrelated to each other in the flocks (mean ± SE relatedness coefficient: 0.06 ± 0.002), although most individuals had at least a few close relatives in their home flock (14.3 ± 0.6% of flock-mates). We genotyped the birds using seven highly polymorphic microsatellite loci, and estimated pairwise relatedness coefficients and relatedness categories (close kin vs. During two winters, we ringed and observed sparrows at feeding stations, and used resightings to identify stable flock-members and to calculate association indices between birds. ![]() aggression, social foraging), but we lack adequate information on the kin structure of sparrow flocks. ![]() This species is a frequent model system for studies of social behaviour (e.g. In this study, we investigated genetic relatedness in feeding aggregations of free-living house sparrows (Passer domesticus) during the nonbreeding season. Social behaviour of group-living animals is often influenced by the relatedness of individuals, thus understanding the genetic structure of groups is important for the interpretation of costs and benefits of social interactions. We discuss possible explanations why sparrow populations may not differ in competitiveness despite the smaller body mass of urban birds. Thus our results did not support the hypothesis that urbanization shifts population structure towards an over-abundance of weak competitors in house sparrows. Moreover, the variance in competitive abilities also did not differ between birds from more and less urbanized habitats. We found that sparrows exhibited consistent individual differences in competitiveness, but these differences were not related either to the degree of urbanization of their original habitats or to their body mass. Here we compared several aspects of their competitiveness (fighting, scrambling and searching for food) in captive mixed flocks of urban and rural birds. We previously showed that wild urban sparrows are smaller and leaner than rural conspecifics, and this difference persists for months under identical captive conditions. To evaluate this hypothesis, we tested whether competitive performance differs between differently urbanized populations of house sparrows Passer domesticus. Existing theory of this topic suggests that the cities' more constant food supplies and lower predation pressure lead to a high proportion of weak competitors in urban populations. How urbanization affects animal populations is in the focus of current ecological research. Our findings indicate that the significance of kin selection may be restricted in some social systems such as winter aggregations of birds. due to competition among relatives as predicted by a recent refinement of kin-selection theory. These results suggest that the pay-offs of reduced aggression towards kin may be low in non-breeding flocks of sparrows, e.g. Fighting success was also unrelated to kinship and the presence of relatives in the flock did not influence the birds’ dominance rank. We found that sparrows did not reduce their aggression towards kin, as neither the frequency nor the intensity of fights differed between close kin and unrelated flock-mates. To test this hypothesis, we investigated whether relatedness affects aggressive behavior during social activities in captive house sparrow (Passer domesticus) flocks. Kin-selection theory predicts that relatedness may reduce the level of aggression among competing group members, leading to indirect fitness benefits for kin-favoring individuals. ![]()
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