Dial Kenneth P
Flight Laboratory, Avian Studies Program, Division of Biological Sciences, University of Montana (UM), Missoula, MT 59812, USA.
Science. 2003 Jan 17;299(5605):402-4. doi: 10.1126/science.1078237.
Flapping wings of galliform birds are routinely used to produce aerodynamic forces oriented toward the substrate to enhance hindlimb traction. Here, I document this behavior in natural and laboratory settings. Adult birds fully capable of aerial flight preferentially employ wing-assisted incline running (WAIR), rather than flying, to reach elevated refuges (such as cliffs, trees, and boulders). From the day of hatching and before attaining sustained aerial flight, developing ground birds use WAIR to enhance their locomotor performance through improved foot traction, ultimately permitting vertical running. WAIR provides insight from behaviors observable in living birds into the possible role of incipient wings in feathered theropod dinosaurs and offers a previously unstudied explanation for the evolution of avian flight.
鸡形目鸟类拍打翅膀通常是为了产生指向地面的气动力，以增强后肢的牵引力。在此，我记录了这种行为在自然和实验室环境中的情况。完全具备空中飞行能力的成年鸟类在前往高处避难所（如悬崖、树木和巨石）时，更倾向于采用翼助斜坡奔跑（WAIR）而非飞行。从孵化之日起，在获得持续空中飞行能力之前，发育中的地面鸟类就利用WAIR通过改善足部牵引力来提高其运动性能，最终实现垂直奔跑。WAIR为从现存鸟类身上可观察到的行为，洞察早期翅膀在有羽毛兽脚亚目恐龙中可能扮演的角色提供了线索，并为鸟类飞行的进化提供了一个此前未被研究过的解释。
