Hummers have an extremely mobile shoulder joint, allowing them to twist the wing in such a way as to generate lift on both the backward and the forward strokes. The front edge of the wing leads on both strokes, and on the backstroke it is the underside of the feathers that face upward, the shoulder rotation having, in effect, turned the wing upside down. In each stroke the bird is able to make use of some of the energy transferred into the motion of air on the previous sweep of its wings - inertia holds the bird’s body essentially stationary. Hummingbird wings do not flex at the wrist or elbow joint like most other birds. Instead they move with short, stiff oar-like motions, at times rotating almost 180 degrees at the shoulder joint. They can quickly change direction with the pitch of their wings and are even capable of brief periods of upside-down flight when startled.  Back to Red Rufous Section