Population colonization history influences behavioral responses of European starlings in personality tests

To understand the processes involved in biological invasions, the genetic, morphological, physiological and behavioral characteristics of invasive populations need to be understood. Many invasive species have been reported to be flying species. In birds, both invaders and migrants encounter novel situations, therefore one could expect that both groups might react similarly to novelty. Here we analyzed the behavioral responses of individuals from three populations of European starling Sturnus vulgaris: a population settled for centuries in a rural region, a population that recently colonized an urban area, and a population of winter migrant birds. We conducted a social isolation test, a novel environment test, a novel food test and a novel object test to explore their reactions towards novelty. We identified and characterized different behavioral profiles for each test. The group of migratory adults appeared to be less anxious in social isolation than the group of urban young. Urban and migrant groups entered the novel environment sooner than rural birds. Shy, bold and intermediate individuals were observed in all three groups when presented with novel food. Finally, the proportion of shy individuals which did not touch the novel object was higher than the proportion of bold individuals in the rural group. Our study emphasizes that neophilia or boldness present in migrant and invasive populations may facilitate the occupation of novel habitats. Our analysis also suggests that mixed reactions of neophobia ensure behavioral flexibility in a gregarious invasive species. Significant statementIn this paper, we show that an invasive species like European starling, Sturnus vulgaris, presents an important flexibility in neophobia and in reaction towards social isolation. These variations depend on the settlement history of populationseven when the birds had been wild-caught as nestlings and hand-raised in standard conditions. This is significant because it highlights possible scenarios of colonization processes. We believe that this manuscript is appropriate for publication by Behavioral Ecology and Sociobiology because it places individuals behavior in the core mechanisms of an ecological phenomenom as biological invasions. Our manuscript enlarges the paradigms related to the ways of coping with novelty in animals. This manuscript has not been published and is not under consideration for publication elsewhere.