Limits to Hummingbird Flight Performance: Ecological and Comparative Perspectives

在动物身上，人们对运动能力的限制知之甚少。蜂鸟在飞行中表现出增强能量能力的新陈代谢专门化，因此是呼吸系统、心血管系统和肌肉系统极端生理学设计的典型例子。因此，对蜂鸟飞行的分析可能揭示脊椎动物运动能力的生物力学和生理学的基本极限，包括人类的运动能力。这项研究将考察不同蜂鸟物种的飞行能力极限，并将确定身体大小、翅膀形态、飞行运动学、空气动力学和呼吸能量学对飞行能力的潜在不同贡献。蜂鸟的种间比较将包括对跨越海拔梯度的悬停飞行性能的研究，由于空气密度和氧气可获得性的物理变化，飞行动物面临着特殊的空气动力学和生理挑战。通过在风洞中对以不同空速飞行的蜂鸟进行向前飞行极限的研究，将加强对悬停飞行的分析。悬停和向前飞行的综合结果将得出关于蜂鸟飞行能力的空气动力学和生理限制的性质的基本结论，更广泛地说，将勾勒出脊椎动物运动生理学的广泛表现界限。

Limits to exercise performance are little understood in animals. Hummingbirds exemplify metabolic specialization for enhanced energetic capacity during flight, and thus represent a prime example of extreme physiological design in respiratory, cardiovascular, and muscular systems. The analysis of hummingbird flight may thus reveal fundamental limits to the biomechanics and physiology of vertebrate locomotor performance, including that of humans. This study will examine limits to flight performance in diverse hummingbird species, and will determine potentially variable contributions of body size, wing morphology, flight kinematics, aerodynamics, and respiratory energetics to flight capacity. Interspecific comparisons of hummingbirds will include studies of hovering flight performance across altitudinal gradients which, because of physical variation in air density and oxygen availability, present particular aerodynamic and physiological challenges to flying animals. Analysis of hovering flight will be augmented by study of limits to forward flight performance carried out on hummingbirds flying at different airspeeds in a wind tunnel. The combined results for hovering and forward flight will yield basic conclusions as to the nature of aerodynamic and physiological constraints on hummingbird flight capacity, and more generally will delineate broad performance limits to vertebrate exercise physiology.