The majority of living things can move both forward and backwards including numerous flightless birds like ostriches, but most birds cannot fly backwards. Over 99% of all the bird species cannot fly backward. The wing structure of most birds has strong muscles for pulling them downwards and weak muscles for moving upwards. These birds rely on the winds to move their wings upwards, and a majority of them cannot fly backwards without the help of the wind. Birds which move back slightly include flycatchers, warblers, egrets and herons using the fluttering method. The only bird which can fly backwards and forward without relying on the wind is the hummingbird.
What Is A Hummingbird?
Hummingbirds are small birds from the Americas with a length of about 5 inches and a weight of less than 0.07 pounds. Nearly one-third of their body weight comes from the muscles they use when flying. Their heart rate can exceed a thousand beats per minute. These birds get their name from the humming sound that is produced by their wings when flapping at a very high frequency. Hummingbirds can hover in midair at a high-speed; the smallest birds flap their wings at a speed of about 80 beats per second while the bigger ones do 12. These birds can fly at a top speed of 15 miles per second while others dive at approximately 22 miles per second. They have a very high metabolism and to conserve heat at night, or when it’s cold, they usually go into a state torpor. At night-time, torpor helps by slowing their heartbeat to about 180 beats per minute and lowers their body temperature to 18°C while slowing down their metabolism. They eat twice their body weight to survive.
Male hummingbirds have a plumage with varying brighter coloration to help them with territorial competition and courtship. The prism-like cells which are on the top layer of their wings, back, breast, gorget and head and the pigmentation of their feathers help brighten the color of their plumage. When sunlight reaches these cells, it split into varying wavelengths which reflects to the observer at a different degree of intensity with the structure of its feathers acting as the diffraction grating. Therefore by simply shifting their position, the feathers of a hummingbird can become vividly green or red.
How Do They Fly Backwards?
These birds have a unique wing structure and muscles which gives them a high level of flight control which lacks in other birds. Just like a helicopter, a hummingbird can fly forward and backwards, diagonally, left to right, right to the left and even hover. Hummingbirds produce 25% of the weight support during an upstroke and 75% during a downstroke; with its wings making figure-eight motions.
The majority of birds fly with downstrokes and upstrokes, and they generate their lifts and power with each stroke. Hummingbirds instead stroke their wings backwards and forward, pivoting about one hundred and eighty degrees at their shoulders to rotate their wings. They can generate lifts for both backward and forward strokes with the tip of their wings tracing a horizontal figure-eight with each beat. A minute twist changes the wing’s angle and the direction of the flight.