摘要翻译：
鸟群是集体动物行为的一个显著例子。这一现象的生动例证是空中展示的一大群椋鸟在黄昏时分聚集在栖息地上空，并以非凡的空间一致性旋转。由于缺乏关于大群的数据，人们对群的进化理由和机械法则都知之甚少。在这里，我们报告了一个定量研究的空中显示。我们测量了多达2700只小鸟的个体三维位置。我们研究了羊群作为一个整体的主要特征--形状、运动、密度和结构--并讨论了这些作为群体现象的突现属性。我们发现羊群相对较薄，大小可变，但比例不变。它们倾向于平行于地面滑动，在转弯过程中，它们的方向相对于运动方向发生变化。单个鸟类之间保持与翼展相当的最小距离。聚集群内的密度不均匀，因为鸟类在边界处比在羊群中心处拥挤得更紧。这些结果构成了第一组关于三维动物聚集的大规模数据。目前关于集体动物行为的模型和理论现在可以用这些结果来检验。
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英文标题：
《An empirical study of large, naturally occurring starling flocks: a
  benchmark in collective animal behaviour》
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作者：
Michele Ballerini, Nicola Cabibbo, Raphael Candelier, Andrea Cavagna,
  Evaristo Cisbani, Irene Giardina, Alberto Orlandi, Giorgio Parisi, Andrea
  Procaccini, Massimiliano Viale, Vladimir Zdravkovic
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最新提交年份：
2008
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分类信息：

一级分类：Quantitative Biology        数量生物学
二级分类：Quantitative Methods        定量方法
分类描述：All experimental, numerical, statistical and mathematical contributions of value to biology
对生物学价值的所有实验、数值、统计和数学贡献
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一级分类：Physics        物理学
二级分类：Statistical Mechanics        统计力学
分类描述：Phase transitions, thermodynamics, field theory, non-equilibrium phenomena, renormalization group and scaling, integrable models, turbulence
相变，热力学，场论，非平衡现象，重整化群和标度，可积模型，湍流
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一级分类：Quantitative Biology        数量生物学
二级分类：Populations and Evolution        种群与进化
分类描述：Population dynamics, spatio-temporal and epidemiological models, dynamic speciation, co-evolution, biodiversity, foodwebs, aging; molecular evolution and phylogeny; directed evolution; origin of life
种群动力学；时空和流行病学模型；动态物种形成；协同进化；生物多样性；食物网；老龄化；分子进化和系统发育；定向进化；生命起源
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英文摘要：
  Bird flocking is a striking example of collective animal behaviour. A vivid illustration of this phenomenon is provided by the aerial display of vast flocks of starlings gathering at dusk over the roost and swirling with extraordinary spatial coherence. Both the evolutionary justification and the mechanistic laws of flocking are poorly understood, arguably because of a lack of data on large flocks. Here, we report a quantitative study of aerial display. We measured the individual three-dimensional positions in compact flocks of up to 2700 birds. We investigated the main features of the flock as a whole - shape, movement, density and structure - and discuss these as emergent attributes of the grouping phenomenon. We find that flocks are relatively thin, with variable sizes, but constant proportions. They tend to slide parallel to the ground and, during turns, their orientation changes with respect to the direction of motion. Individual birds keep a minimum distance from each other that is comparable to their wingspan. The density within the aggregations is non-homogeneous, as birds are packed more tightly at the border compared to the centre of the flock. These results constitute the first set of large-scale data on three-dimensional animal aggregations. Current models and theories of collective animal behaviour can now be tested against these results.
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PDF链接：
https://arxiv.org/pdf/802.1667