Data from: Flight reconstruction of two European enantiornithines (Aves, Pygostylia) and the achievement of bounding flight in Early Cretaceous birds

Birds today follow different aerial strategies to deal with the high costs of flapping flight. Intermittent flight, through either flap-gliding or bounding, is commonly used among small birds as a strategy to optimize aerial efficiency. The broad morphological disparity of the different lineages of Mesozoic birds suggests that a range of aerial strategies could have evolved early in avian evolution. Based on biomechanics and aerodynamic theory, this study reconstructs the flying properties of two small enantiornithines from the Lower Cretaceous fossil site of Las Hoyas (Spain), Concornis lacustris and Eoalulavis hoyasi. Our results show that the short length of their wings in relation to their body masses were suitable for flying through strict flapping and intermittent bounds, but not through facultative glides. Aerodynamic models indicate that the power margins of these birds were sufficient to sustain bounding flight. Our results thus suggest that C. lacustris and E. hoyasi would have increased aerial efficiency through bounding flight, just as many small passerines and woodpeckers do today. Intermittent bounding appears to have evolved early in the evolutionary history of birds, at least 126 million years ago.现今鸟类演化出多种飞行策略以应对振翅飞行的高昂能量成本。其中，通过振翅滑翔或弹跳飞行实现的间歇飞行，是小型鸟类普遍采用的优化飞行效率的策略。中生代鸟类各支系间广泛的形态分异度表明，多种飞行策略可能在鸟类演化早期就已出现。本研究基于生物力学（biomechanics）与空气动力学（aerodynamics）理论，对西班牙拉斯霍亚斯（Las Hoyas）下白垩统化石点发现的两种小型反鸟类（enantiornithines）——湖栖康考鸟（Concornis lacustris）与霍亚斯始翼鸟（Eoalulavis hoyasi）的飞行特性进行了重建。研究结果显示，相较于体重而言较短的翼展，适配于纯振翅飞行与间歇弹跳飞行，但不适用于兼性滑翔。空气动力学模型表明，这两种鸟类的功率余量足以支撑弹跳飞行。由此，本研究结果表明，湖栖康考鸟与霍亚斯始翼鸟可通过弹跳飞行提升飞行效率，这与现今众多小型雀形目鸟类及啄木鸟的飞行策略一致。间歇弹跳飞行模式似乎在鸟类演化早期就已出现，其起源时间至少可追溯至1.26亿年前。