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Is gliding flight more easier than flapping flight in birds? does an eagle use a flapping filght too?
When birds flap, the stroke of their downbeat moves the wing tips forward and downward. The wingtips make a loop at the bottom of the downstroke, and as the wings move up, the wing tips move upward and backward. In the downstroke, the pressure is higher below the wing than above, causing lift. And as they move forward, the rush of air on their airfoil wings causes more lift. But because flapping birds have smaller wings than soaring birds, they must move forward faster to stay in the air.

.Soaring birds take advantage of thermals and updrafts by flying in a circle. The rising air carries them higher and higher in a spiral. They couldn't simply hold still and go straight up because without moving forward on their airfoil wings, they would simply drop to the ground. But the problem with circling is they don't go in any special direction. So when migrating birds soar on a thermal, they rise as high as the thermal will carry them with their wings spread, and then they pull back the wings into a more narrow point and glide in the direction they want to move.

Soaring birds that wish to stay aloft without flapping in normal wind usually fly into the wind for lift. But that same wind that holds them up slows their forward movements. In order to get somewhere, soaring birds make delicate adjustments to turn slightly now and then. They gain lift for a while and then lose altitude as they head where they actually want, and then gain lift again. This is why gulls usually fly in a more zig-zaggy pattern than many other birds.

Like soaring birds, flapping birds have their easiest time staying up when they're facing the wind, but their easiest time moving forward when being pushed by the wind. Since their forward momentum and the lift they get from flapping is more important than the lift they get from the wind or air currents, they can get where they want to if they just point themselves in the right direction and go.

When an eagle first leaves the ground, it gains altitude by flapping its wings. The flapping motion causes air to flow faster over the top of the wings, and the bird rises.

Sometimes, an eagle is able to take advantage of natural currents of air to help it rise. When wind runs into a hill or a mountain, it is forced upward - and the eagle can go along for the ride. This kind of air current is called a slope updraft.


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