caa a22 4500 465782132 CHVBK 20180323111958.0 cr unu---uuuuu 170327e19900401xx s 000 0 eng 10.1007/BF00178317 doi (NATIONALLICENCE)springer-10.1007/BF00178317 Ekman Jan Department of Zoology, University of Stockholm, S-106 91, Stockholm, Sweden aut Alliances in winter flocks of willow tits; effects of rank on survival and reproductive success in male-female associations [Elektronische Daten] [Jan Ekman] Summary: The value of being dominant in winter flocks of willow tits may not only be a matter of personal survival for males, although their survival probability was highest among flock members. Winter flocks of willow tits contain male-female subunits, and the dominant pair may be viewed as an alliance based on mutual benefits. Dominant males provide their mates with protection in winter, and females return the help in reproductive success. Survival was directly related to rank only within sexes. Mates of dominant males survived significantly better than low-ranked males even though these females were subordinate to these males in direct interactions. Mates of dominant males were relatively spared from costs of low rank as they were subject to aggression less often than expected. Presumably dominant males prevented such attacks, as they excluded other flock members from high tree sections where their mates fed. Males should gain from improving the survival probability of their mates since it was not always possible to replace lost mates in spring populations having a male-biased sex ratio. Dominance in avian winter flocks may thus have more indirect effects than merely to improve the personal survival probability through resource priority. The benefits of being a dominant suggest that subordinate willow tits join groups because there is no space available for them to take up a territory as dominants. Springer-Verlag, 1990 Behavioral Ecology and Sociobiology Springer-Verlag 26/4(1990-04-01), 239-245 0340-5443 26:4<239 1990 26 265 https://doi.org/10.1007/BF00178317 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00178317 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Ekman Jan Department of Zoology, University of Stockholm, S-106 91, Stockholm, Sweden aut NATIONALLICENCE 773 0- Behavioral Ecology and Sociobiology Springer-Verlag 26/4(1990-04-01), 239-245 0340-5443 26:4<239 1990 26 265 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer