Social competence i.e., defined as the ability to adjust the expression of social behaviour to the available social information, is known to be influenced by early-life conditions. Brood size might be one of the factors determining such early conditions, particularly in species with extended parental care. We here tested in ravens, whether growing up in families of different sizes affects the chicks’ responsiveness to social information. We experimentally manipulated the brood size of 20 captive raven families, creating either small or large families. Simulating dispersal, juveniles were separated from their parents and temporarily housed in one of two captive non-breeder groups. After five weeks of socialization, each raven was individually tested in a playback setting with food-associated calls from three social categories: sibling, familiar unrelated raven they were housed with, and unfamiliar unrelated raven from the other non-breeder aviary. We found that individuals reared in small families were more attentive than birds from large families, in particular towards the familiar unrelated peer. These results indicate that variation in family size during upbringing can affect how juvenile ravens value social information. Whether the observed attention patterns translate into behavioural preferences under daily life conditions remains to be tested in future studies.

The Supplementary material contains Tables and Figures of additional analyses referred to in the manuscript.

The .csv file contains the behavioral responses of tested individuals and their life history, including data referring to their family ID and brood size.

The R code describes step by step the statistical analyses reported in the current manuscript.