HOW DO EAGLES GLIDE, WITHOUT FLAPPING THEIR WINGS..?

When people see the Eagle flying , they may think that how do they do it without flapping their wings....?

If you watch an eagle's movement through binoculars, you will see that even though the bird appears to be gliding lazily, it is actually very active. Its outer wing feathers and tail  feathers are in constant motion, catching up-drafts of warm air, and steering the bird through the air currents. Like other objects, which are heavier that air, birds in flight are constantly falling. When a bird is in an up-draft of warm air, it is carried up more quickly than it falls.  At this time, it can fly higher. The bird now tries to keep itself in this column of air by steering with its wing and tail feathers. When the birds moves into a column of downward moving cooler air, it falls rapidly.  However , it now uses its wings to help it glide, as quickly as possible, into another column of upward moving warm air. The speed that the bird attained while gliding downward in the 'cool column' enables it to sweep upward more quickly when it enters the 'warm column'.