by Rex Trulove

Created on: October 24, 2008   Last Updated: November 03, 2008

More than one bird flies backward, however the one most often thought of as having the ability is the hummingbird. This is because they can hover or fly in any direction with seeming ease.

There are many different species of hummingbird, however all have a few things in common. All of them are extremely small and light, all have long, narrow beaks and tongues, and most important for the ability to fly backward, all of them use the same wing stroke pattern.

In nearly all other birds, the wing stroke pattern is primarily up and down, though in some the upward stroke is slightly forward and the backward stroke is slightly backward. This is a diagonal pattern, but still primarily up and down.

There is less air resistance on the top of the wing since the feathers are downward facing. However the bottom side of the wing has a great deal of air resistance, for exactly the same reason the top of the wing lacks it. This gives birds a great deal of lift and allows them to fly, except for those that are permanently flightless. (An exception in flightless birds is the penguin. Though it can't fly through the air, it can fly through water, using the same method mentioned here. This is seen in underwater photographs.)

Hummingbirds have a unique wing stroke pattern though. The wings have the same air resistance properties that the wings of other birds have. But instead of primarily up and down, the wing stroke is made in a sideways figure eight. Filming the birds with high-speed film, then slowing it down tremendously, because of the speed with which they beat their wings, displays this and in fact only in this way can we see it. However, in slow motion photography, the pattern of the wing is apparent.

On the downward stroke, the wing feathers are fully extended to resist the air pressure below the wing, giving lift. At the same time, they are swept backward, with the wings tilting through the stroke to smoothly decrease the lift. The wings are then brought up and forward, still at an angle, and back down again in a smooth motion. Finally, the wing is again brought up so it is ready for the downward stroke.

Many people believe that the aerial acrobatics of the hummingbird are totally due to the speed of the wing beats. This is indeed important, however without the figure eight pattern, none of the striking movements would be possible. By simply slightly changing the angle at which the wing and feathers attack the air, hummingbirds can hover, fly backward, pivot in place, and fly

• 1
• 2
• Next Page >>