The wisdom of crowds emerges in flocks of thousands of migrating songbirds.

Abstract

While enhanced decision-making in larger groups, known as the wisdom of crowds, has been demonstrated in controlled experimental conditions, the intractability of observing large-scale wild groups has limited the availability of evidence from natural systems. Addressing this challenge, we analyze migratory trajectories of flocks of thousands of wild songbirds extracted from 23 years of weather radar data across the Great Lakes of North America. We show that the wisdom of crowds emerged: Larger flocks oriented more accurately toward their population's migratory direction than smaller flocks. This likely emerged through the many-wrongs effect, with individual errors averaged out across flocks. Furthermore, flock size declined over time, a trend that may erode navigational performance and carry important ecological implications amid anthropogenic population fragmentation. Together, these findings reveal how the wisdom of crowds emerges in natural systems and underscore its role in shaping movement and ecological resilience in social animals.