) Birds produce thrust by flapping their wings within a figure-eight movement. About the downstroke, air hits The underside of your wing and is deflected previous the fowl, propelling it ahead. Increasing the depth of each wingstroke will increase airspeed and lifts the fowl. Telegram was introduced in 2013 by https://www.fodors.com/community/profile/rudolphboyle9629/about-me