To flap their wings at this speed, hummingbirds have evolved huge pectoral muscles.

To flap their wings at this speed, hummingbirds have evolved giant pectoral muscles that comprise over a third of some species’ bodyweight. But the real secret to their fine-tuned flight is all in the wrist. Most birds only generate lift on the downstroke of each flap, while using the upward recovery stroke to set up their next wing beat. Hummingbirds however, turn their wrists during the upstroke, changing their wing’s angle to flap in a figure 8 pattern that continually generates lift throughout their wingbeats.