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Brood sex ratio adjustment in collared flycatchers (Ficedula albicollis): results differ between populations

  • Balázs Rosivall
  • J Török
  • Dennis Hasselquist
  • Staffan Bensch
Publishing year: 2004
Language: English
Pages: 346-351
Publication/Series: Behavioral Ecology and Sociobiology
Volume: 56
Issue: 4
Document type: Journal article
Publisher: Springer

Abstract english

Recently, a number of studies have found adaptive brood sex ratio (BSR) manipulation in birds. The reason for such manipulations is thought to be the different reproductive value of male and female nestlings. Several studies have found that parental quality and food supply can affect BSR, however results are sometimes inconsistent between species and populations. We investigated BSR patterns in a Hungarian population of Collared Flycatchers (Ficedula albicollis) and compared the results with those obtained in a previous study of the same species in Sweden. We found two significant differences. First, the male forehead patch size, a heritable, sexually selected trait, affected the brood sex ratio in the Swedish population, but not in our Hungarian study population. This difference might be a consequence of the different information content of the forehead patch size in the two populations. Second, a seasonal shift in BSR (more sons late in the season) was observed in the Hungarian, but not in the Swedish population.


  • Biological Sciences


  • Molecular Ecology and Evolution Lab
  • ISSN: 1432-0762
Dennis Hasselquist
E-mail: dennis [dot] hasselquist [at] biol [dot] lu [dot] se



+46 46 222 37 08



Research group


Doctoral students and postdocs

Research fellows


Jacob Roved

PhD Students, main supervisor

PhD Students, assistant supervisor


Interview about my research in the Swedish podcast "Forskarn & jag"