Hummingbirds have many skeletal and flight muscle adaptations which allow the bird great agility in flight. Muscles make up 25-30% of their body weight, and they have long, blade-like wings that, unlike the wings of other birds, connect to the body only from the shoulder joint. This adaptation allows the wing to rotate almost 180°, enabling the bird to fly not only forward but fly backwards, and to hover in front of flowers as it feeds on nectar and insects. During hovering, ruby-throated hummingbird wings beat 55 times per second, 61 times per second when moving backwards, and up to 75 times per second when moving forward. This female ruby-throated hummingbird was one of many fighting over a nearby feeder in Rockaway, NJ USA. I captured her with my Nikon D3100 and the Nikon 70-300mm zoom lens.