By Yunkyu Sohn
An experimental study shows that even birds have hierarchical social orders among them. By using delayed correlation analysis on birds’ flight directions, the authors uncover a weighted directed influence network of the bird flock. The topological structure of the network validates the presence of distinct asymmetric hierarchy within the bird community. This result implies that the long-held proximal interaction topology assumption in group dynamics simulation research should be replaced by the implementation of highly nondemocratic network structures.