Energetic benefits of social information for movement in patchy landscapes

Movement is costly, and animals are under strong selective pressure to move efficiently; however, in patchy, dynamic landscapes, decision-making is inherently uncertain. We quantify the energy savings achieved by using up-to-date information presented within social cues to reduce movement costs. We use an agent-based model, which is founded on realistic aeronautical rules and is parametrized on the Andean condor (Vultur gryphus), to study movement in patchy landscapes. By explicitly considering altitude, flight results in a sequence of soaring and gliding in three-dimensional space. We investigate how the cost of movement to an overall goal varies when birds use social information from others that are either fixed in space or moving collectively to the common goal, and under different risk-taking speed strategies, from slow and cautious to fast and risky. The value of social information is operationalized as energy savings in units of the basal metabolic rate (BMR). Under low predictability, agents with intermediate risk and high social-information use exhibit lowest movement costs, with up to 41% energy savings over asocial movement. By extending classical aeronautical theory to social and variable environments, we demonstrate the adaptive value of social information for efficient movement in patchy, unpredictable landscapes.