Balancing risks and information gathering: prospecting strategies in a territorial raptor

Abstract Dispersal decisions strongly influence individual survival and reproductive success, and it appears crucial to unravel the mechanisms driving these choices to fully understand population dynamics. By visiting conspecifics’ breeding sites, prospectors gather social information that inform their dispersal decision, but this strategy comes at high costs, as it involves significant risks of territorial aggression by breeding individuals. When dispersing, individuals must therefore balance acquiring valuable social information with avoiding conflicts with conspecifics, a trade-off that has been very rarely studied and remains misunderstood. To address this gap, we investigated nest-visiting behaviour in 61 GPS-tracked immature Golden eagles (Aquila chrysaetos), a species whose prospectors face costly territorial aggression. Despite the strong risk of agonistic interactions, most individuals prospected close to adult nests, suggesting a strong benefit from social information. Prospecting increased with age, suggesting a growing need for social information before territory settlement. Yet, individuals mostly visited unoccupied sites and outside the breeding season, likely to reduce the risk of aggression. Our study suggests that territorial aggression is a key factor shaping how, when, and by whom social information is gathered, providing new insights into how animals navigate trade-offs between information acquisition and survival in heterogeneous landscapes.