PDF(Pubmed)
Abstract：
Many bird species commonly aggregate in flocks for reasons ranging from predator defense to navigation. Available evidence suggests that certain types of flocks-the V and echelon formations of large birds-may provide a benefit that reduces the aerodynamic cost of flight, whereas cluster flocks typical of smaller birds may increase flight costs. However, metabolic flight costs have not been directly measured in any of these group flight contexts [Zhang and Lauder, J. Exp. Biol. 226, jeb245617 (2023)]. Here, we measured the energetic benefits of flight in small groups of two or three birds and the requirements for realizing those benefits, using metabolic energy expenditure and flight position measurements from European Starlings flying in a wind tunnel. The starlings continuously varied their relative position during flights but adopted a V formation motif on average, with a modal spanwise and streamwise spacing of [0.81, 0.91] wingspans. As measured via CO2 production, flight costs for follower birds were significantly reduced compared to their individual solo flight benchmarks. However, followers with more positional variability with respect to leaders did less well, even increasing their costs above solo flight. Thus, we directly demonstrate energetic costs and benefits for group flight followers in an experimental context amenable to further investigation of the underlying aerodynamics, wake interactions, and bird characteristics that produce these metabolic effects.
摘要：
许多鸟类通常聚集在群中，原因从捕食者防御到航行。现有证据表明，某些类型的羊群-大型鸟类的V和梯队编队-可能会提供降低飞行空气动力学成本的好处，而小型鸟类典型的集群群可能会增加飞行成本。然而,在任何这些团体飞行环境中，代谢飞行成本都没有直接测量[Zhang和Lauder，J、实验。Biol.226,jeb245617(2023)]。这里,我们测量了两三只鸟的小组飞行的能量收益，以及实现这些收益的要求，使用在风洞中飞行的欧洲八哥的代谢能量消耗和飞行位置测量。八哥在飞行过程中不断改变其相对位置，但平均采用了V形图案，模态翼展和流向间距为[0.81，0.91]翼展。通过二氧化碳生产测量，跟班鸟的飞行成本与它们各自的单飞基准相比显著降低。然而,相对于领导者而言，位置可变性更大的追随者表现不佳，甚至增加他们的成本超过单飞。因此，我们在适合于进一步研究潜在空气动力学的实验背景下，直接证明了团体飞行追随者的能量成本和收益，唤醒互动，和产生这些代谢作用的鸟类特征。
