When birds take to the air in a large group, they typically either fly in a V-formation or in a swarmlike cluster. Both have their benefits: the V-shape is aerodynamically efficient, saving geese and other birds energy during flight, while cluster flocking can help birds like pigeons guard against predators. But the cluster has one big disadvantage, according to a study published online today in Nature. When researchers followed 18 pigeons with GPS, they found that the birds gained neither an aerodynamic advantage nor added energy efficiency when flying in a cluster. In fact, the team believes that it takes pigeons more energy to fly in a flock than to fly solo. So why do they do it? In addition to predator protection, the researchers speculate that cluster flocking may help the birds navigate; a follow-the-crowd mentality.
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