The cost of being alone: the fate of floaters in a population of cooperatively breeding pied babblers Turdoides bicolor

The occurrence of group‐living behaviour has often been explained by the benefits individuals receive through cooperation; including increased reproductive output, vigilance against predators, and load‐lightening behaviour. However, to fully understand the benefits of group‐living, it is important to quantify the costs of living alone. Here, we look at the fate of floaters (individuals who have no fixed territory and remain alone for extended periods) in a population of cooperatively breeding pied babblers Turdoides bicolor . We found that individuals spent less time foraging and more time vigilant for predators when found as a floater compared to when they were in a group. Consequently, they suffered a continuous loss of body mass, with long‐term floaters suffering the highest losses. This had a long‐term effect: floaters that eventually did regain a position in a group usually entered as helpers, in contrast to dispersers, who usually entered a new group as breeders. This high cost of living alone highlights the benefits of group‐living and may help to understand patterns of delayed dispersal in some social species.