European shags optimize their flight behavior according to wind conditions
European shags optimize their flight behavior according to wind conditions
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DOI：
10.1242/jeb.131441
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发表时间：
2016-02-01
影响因子：
2.8
通讯作者：
Daunt, Francis
中科院分区：
文献类型：
--
作者：
Kogure, Yukihisa;Sato, Katsufumi;Daunt, Francis
空气动力学导致了鸟类飞行的两个特征速度：最小功率速度和最大航程速度。最小功率速度要求每单位时间保持在空中的最低能量消耗率，最大航程速度要求每单位消耗的能量最大限度地增加飞行距离。因此，如果鸟类的目标是在一定风力条件下将运输成本降至最低，预计它们将以最大航程速度飞行。此外，预计起飞受到风速和风向的强烈影响。为了研究风力条件对起飞和巡航飞行行为的影响，我们在14只欧洲凤尾长尾凤尾上安装了GPS记录仪来测量位置和地面速度，并在颈部安装了加速度计来记录翅膀拍打频率和强度。在部署期间，记录了当地的风力情况。无论目的地如何，飞机总是迎风起飞，起飞时间与风速呈负相关。我们将巡航阶段的地面速度和方向与风速和方向相结合来估计空气速度和方向。虽然地面速度变化很大，但空气速度相对稳定，尽管在强劲的逆风中，由于更强的机翼拍击，它会显著增加。逆风增加的空气速度表明鸟类以最大航程速度飞行，而不是以最小功率速度飞行。我们的研究表明，欧洲的shag积极地调整他们的飞行行为，利用风力来最小化起飞和巡航飞行的成本。
Aerodynamics results in two characteristic speeds of flying birds: the minimum power speed and the maximum range speed. The minimum power speed requires the lowest rate of energy expenditure per unit time to stay airborne and the maximum range speed maximizes air distance traveled per unit of energy consumed. Therefore, if birds aim to minimize the cost of transport under a range of wind conditions, they are predicted to fly at the maximum range speed. Furthermore, take-off is predicted to be strongly affected by wind speed and direction. To investigate the effect of wind conditions on take-off and cruising flight behavior, we equipped 14 European shags Phalacrocorax aristotelis with a back-mounted GPS logger to measure position and hence ground speed, and a neck-mounted accelerometer to record wing beat frequency and strength. Local wind conditions were recorded during the deployment period. Shags always took off into the wind regardless of their intended destination and take-off duration was correlated negatively with wind speed. We combined ground speed and direction during the cruising phase with wind speed and direction to estimate air speed and direction. Whilst ground speed was highly variable, air speed was comparatively stable, although it increased significantly during strong head winds, because of stronger wing beats. The increased air speeds in head winds suggest that birds fly at the maximum range speed, not at the minimum power speed. Our study demonstrates that European shags actively adjust their flight behavior to utilize wind power to minimize the costs of take-off and cruising flight.