title: Collective Decision-Making in Homing Pigeons: Larger Flocks Take Longer to Decide but Do Not Make Better Decisions.
abstract: Social animals routinely are challenged to make consensus decisions about movement directions and routes. However, the underlying mechanisms facilitating such decision-making processes are still poorly known. A prominent question is how group members participate in group decisions. We addressed this question by examining how flocks of homing pigeons (Columba livia) decide their homing direction. We released newly formed flocks varying in size and determined the time taken to choose a homing direction (decision-making period) and the accuracy of that choice. We found that the decision-making period increases exponentially with flock size, which is consistent with a participatory decision-making process. We additionally found that there is no effect of flock size on the accuracy of the decisions made, which does not match with current theory for democratic choices of flight directions. Our combined results are better explained by a participatory choice of leaders that subsequently undertake the flock directional decisions. However, this decision-making model would only entirely fit with our results if leaders were chosen based on traits other than their navigational experience. Our study provides rare empirical evidence elucidating decision-making processes in freely moving groups of animals.
authors: Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.|Departamento de Biologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal do Maranhão, Campus do Bacanga, São Luís, MA, Brazil.
authors: Carlos D
authors: CD
authors: Santos
authors: Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.|Department of Biology, University of Konstanz, Konstanz, Germany.
authors: Sebastian
authors: S
authors: Przybyzin
authors: Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.|Department of Biology, University of Konstanz, Konstanz, Germany.
authors: Martin
authors: M
authors: Wikelski
authors: Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany.|Department of Biology, University of Konstanz, Konstanz, Germany.
authors: Dina K N
authors: DK
authors: Dechmann
mesh_terms: D000818:Animals; D002755:Choice Behavior; D010856:Columbidae / Q000502:physiology*; D006127:Group Structure; D006702:Homing Behavior; D008399:Mass Behavior; D008960:Models, Psychological; D012930:Social Dominance; D013997:Time Factors