Playing with the rope: a house sparrow behaviour related to its breeding activity.

The house sparrow (Passer domesticus) is a gregarious generalist species, which makes it a good model for studying play. However, play has not been described for this species so far. We describe play behaviour in house sparrows for the first time, quantifying all play and play-related behaviours, searching for differences between the different sexes and ages, the possible association with reproductive success and the diffusion of this behaviour in the population. All behaviours were recorded from the end of 2018 breeding season to the start of the new one in 2019. Behaviours were classified into four levels of interaction of increasing complexity and intensity. Results showed that play behaviour was restricted to the breeding season, adult males played more often than the rest of the groups, and their behaviours correlated with the number of recruits they produced. Moreover, "Maximum Level" of play of the mothers significantly and positively correlated with that of their offspring, and the "Maximum Level" of an individual with the proportion of playing siblings. Despite the limitations of the present study, our results point out the existence of benefits for the reproductive success of playing individuals.