Flight Speeds of Birds in Relation to Energetics and Wind Directions
Flight Speeds of Birds in Relation to Energetics and Wind Directions
复制标题
鸟类飞行速度与能量和风向的关系
DOI：
10.2307/4083964
复制
发表时间：
1971
期刊：
影响因子：
--
通讯作者：
K. Schmidt
中科院分区：
文献类型：
--
作者：
V. Tucker;K. Schmidt
最近，精确测量鸟类在风洞中自由飞行的能量消耗已经成为可能（Tucker, 1968, 1969）。测量结果表明，动力消耗受空气速度和飞行角度的影响，飞行角度可能是水平、上升或下降。由于风洞中的风速和飞行角度是由研究者选择的，我们感兴趣的是确定鸟类在自然条件下飞行时是否会选择使其能量消耗最小的风速。在自然界中，精确测量空气速度和飞行角度是很困难的。必须测量鸟和风的速度矢量，然后必须通过矢量加法来确定鸟相对于空气的运动。两个向量都可以随时间和空间变化。由于裸眼通常无法测量距离和角度，因此需要相对精密的跟踪和记录设备，而精确的速度测量必须基于距离和角度。虽然对鸟类飞行速度的许多估计已经发表（Baker, 1922; Cooke, 1937; Cottam et al., 1942; McCabe, 1942; brown and Goodwin, 1943; Spiers, 1945; Meinertzhagen, 1955; Pearson, 1961; Thompson, 1961; Lanyon, 1962; Schnell, 1965; Lokemoen, 1967; Michener and Walcott, 1967），但由于对方法的描述不完整，大多数估计的准确性无法评估。大多数估计都是基于地面速度，很少或根本没有关于风速的信息。这些鸟经常被汽车或飞机追逐，或者受到其他方面的干扰，上升或下降的角度没有被测量。我们用双经纬仪系统测量了自然界中鸟类相对于空气和地面的速度。在这项技术中，两名观测者在不同的位置操作望远镜，观察到这只鸟。望远镜的视线的水平角度和一个垂直角度同时记录在已知的时间。根据这些数据，可以重建鸟在每个时间点的空间位置，从而确定三维速度矢量。通过跟踪氦气球，可以以类似的方式测量二维的风速矢量。
RECENTLY it has become possible to measure accurately the power expenditures of birds flying freely in a wind tunnel (Tucker, 1968, 1969). The measurements show that power expenditure is influenced by the air speed and the angle of flight, which may be level, ascending, or descending. As the air speed and angle of flight in a wind tunnel are chosen by the investigator, we were interested in determining if birds flying in natural conditions choose air speeds that minimize their power expenditures. Accurate measurements of air speed and angle of flight in nature are difficult to make. The velocity vectors of both the bird and the wind must be measured, and then the motion of the bird relative to the air must be determined by vector addition. Both vectors may change in time and space. As the unaided human eye usually is incapable of measuring the distances and angles on which accurate measurements of the velocities must be based, relatively elaborate tracking and recording devices are needed. Although many estimates of bird flight speeds have been published (Baker, 1922; Cooke, 1937; Cottam et al., 1942; McCabe, 1942; Broun and Goodwin, 1943; Spiers, 1945; Meinertzhagen, 1955; Pearson, 1961; Thompson, 1961; Lanyon, 1962; Schnell, 1965; Lokemoen, 1967; Michener and Walcott, 1967), the accuracy of most of them cannot be evaluated because the descriptions of methodology are incomplete. Most estimates are for ground speed with little or no information on wind velocity. Often the birds were chased by automobiles or aircraft, or were otherwise disturbed, and angles of ascent or descent were not measured. We measured velocities with respect to air and ground of birds in nature by using a double theodolite system. In this technique, the bird is sighted on through telescopes operated by two observers at different locations. The horizontal angles and one vertical angle of the lines of sight of the telescopes are recorded simultaneously and at known times. The position of the bird in space at each time can be reconstructed from these data so that three-dimensional velocity vectors can be determined. Wind velocity vectors in two dimensions can be measured in a similar manner by tracking helium balloons.