Melanin-based colour polymorphism signals aggressive personality in nest and territory defence in the tawny owl (Strix aluco)

Arnaud Da Silva, Valentijn van den Brink, Guillaume Emaresi, Ester Luzio, Pierre Bize, Amelie N. Dreiss, Alexandre Roulin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


Nest and territory defence are risky and potentially dangerous behaviours. If the resolution of life history trade-offs differs between individuals, the level of defence may also vary among individuals. Because melanin-based colour traits can be associated with life history strategies, differently coloured individuals may display different nest and territory defence strategies. We investigated this issue in the colour polymorphic tawny owl (Strix aluco) for which plumage varies from dark to light reddish melanic. Accordingly, we found that (1) our presence induced a greater response (flying around) from dark-coloured than light-coloured females and (2) dark reddish males suffered lower nest predation rates than light-coloured males. In experimentally enlarged broods, the probability that females reacted after we played back the hoot calls of a stranger male was higher if these females were lighter reddish; the opposite pattern was found in experimentally reduced broods with dark parents being more reactive than light parents. Finally, darker females alarmed more frequently when paired with a light than with a dark male, suggesting that partners adjust their behaviour to each other. We also tested whether colouration is used as a signal by conspecifics to adjust the level of their defensive behaviour. Accordingly, breeding females responded more vigorously to a dark than a light reddish stuffed tawny owl placed beside their nest. We conclude that melanin-based colouration is a signal of alternative nest and territory defence behaviour that depends on ecological factors.

Original languageEnglish
Pages (from-to)1041-1052
Number of pages12
JournalBehavioral Ecology and Sociobiology
Issue number7
Early online date5 Apr 2013
Publication statusPublished - Jul 2013

Bibliographical note

We thank Wolf Harmening for his advice and Rory Hambling (UK) for providing us with the sample of the hooting male owl. The study was financed by the Swiss National Science Foundation to AR (grant no. 31003A_120517). We are grateful to
the three reviewers who provided useful comments on an earlier version of the text.


  • Nest defence
  • Colour polymorphism
  • Personality
  • Pheomelanin
  • Predation


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