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Behavioural syndrome between boldness and aggressiveness and link with reproductive success in a wild bird population

Cite this dataset

Tamin, Thibault et al. (2023). Behavioural syndrome between boldness and aggressiveness and link with reproductive success in a wild bird population [Dataset]. Dryad.


Boldness, defined as the behavioural response of individuals when facing a risky situation, is a major personality trait and often phenotypically correlates with other behavioural traits, in particular aggressiveness, exploration behaviour and neophobia. Yet, whether such links result from among-individual correlations, i.e. form behavioural syndromes sensu stricto, is often ignored and whether such syndromes may yield individual fitness benefits, and thus be selected for, remains poorly explored. We measured boldness as the nest defence behaviour against a dummy nest predator in a natural population of a small passerine bird, the collared flycatcher, Ficedula albicollis, and investigated the existence of a behavioural syndrome between boldness and two other behavioural traits, aggressiveness (measured as the agonistic response to competitors) and neophobia (measured as the behavioural response to a novel object in a known environment). Then we assessed the links between this potential syndrome and reproductive success, measured as fledging and recruitment success. Boldness score differed between the sexes and depended on whether the partner was present during the test. Nevertheless, it was repeatable, showing that boldness can be considered as a personality trait in our population. We found a positive among-individual correlation between boldness and aggressiveness, showing the existence of a behavioural syndrome between both personality traits. This syndrome was related to reproductive success: the number of fledged young (but not recruitment probability) increased with one integrative value of the boldness–aggressiveness syndrome. Conversely, boldness score was not correlated with neophobia. Our results thus clearly reveal a behavioural syndrome between boldness and aggressiveness with possible consequences for reproductive success in the study population, and therefore raise the question of the evolutionary implications of such a behavioural syndrome.


The dataset was collected during several field word between 2011 and 2014 at the Island of Gotland (Sweden) where the population of collared flycatcher was monitored since 1980s. We performed univariate and bivariate Bayesian model (MCMCglmm) to identify the presence of a boldness trait and of behavioural syndrome between this latter and two others behavioural traits. Moreover we studied the link between the reproductive success and the aggressiveness-boldness syndrome in order to produce a MS accepted for publication in Animal Behaviour.


Claude Bernard University Lyon 1