Askew G N, Ellerby D J
Institute of Integrative and Comparative Biology, University of Leeds, Leeds LS2 9JT, UK.
Biol Lett. 2007 Aug 22;3(4):445-8. doi: 10.1098/rsbl.2007.0182.
A major goal of flight research has been to establish the relationship between the mechanical power requirements of flight and flight speed. This relationship is central to our understanding of the ecology and evolution of bird flight behaviour. Current approaches to determining flight power have relied on a variety of indirect measurements and led to a controversy over the shape of the power-speed relationship and a lack of quantitative agreement between the different techniques. We have used a new approach to determine flight power at a range of speeds based on the performance of the pectoralis muscles. As such, our measurements provide a unique dataset for comparison with other methods. Here we show that in budgerigars (Melopsittacus undulatus) and zebra finches (Taenopygia guttata) power is modulated with flight speed, resulting in U-shaped power-speed relationship. Our measured muscle powers agreed well with a range of powers predicted using an aerodynamic model. Assessing the accuracy of mechanical power calculated using such models is essential as they are the basis for determining flight efficiency when compared to measurements of flight metabolic rate and for predicting minimum power and maximum range speeds, key determinants of optimal flight behaviour in the field.
飞行研究的一个主要目标是确定飞行所需的机械功率与飞行速度之间的关系。这种关系对于我们理解鸟类飞行行为的生态学和进化至关重要。目前确定飞行功率的方法依赖于各种间接测量，这导致了关于功率-速度关系形状的争议，以及不同技术之间缺乏定量一致性。我们采用了一种新方法，基于胸肌的性能来确定一系列速度下的飞行功率。因此，我们的测量提供了一个独特的数据集，可与其他方法进行比较。在这里，我们表明，虎皮鹦鹉（Melopsittacus undulatus）和斑胸草雀（Taenopygia guttata）的功率随飞行速度而调节，从而形成U形的功率-速度关系。我们测量的肌肉功率与使用空气动力学模型预测的一系列功率非常吻合。评估使用此类模型计算的机械功率的准确性至关重要，因为与飞行代谢率测量值相比，它们是确定飞行效率的基础，也是预测最小功率和最大航程速度的基础，而最小功率和最大航程速度是野外最佳飞行行为的关键决定因素。
