Birds flap their wings with an up-and-down motion, which enables them to move forward. In order to maintain the correct angle of attack, the entire wingspan needs to twist automatically during each downward stroke. This twisting motion allows the wings to align with the direction of travel.
So, how do birds fly?
The Basics of Flight
There are two main forces that allow birds to fly: lift and thrust.
- Lift is the force that pushes a bird up and away from the ground. It is created by the shape of the bird's wings. When a bird flaps its wings, it creates a difference in air pressure between the top and bottom of the wing. The air pressure is lower on the top of the wing, which creates a force that pushes the bird up.
- Thrust is the force that propels a bird forward. It is created by the bird's wings as they move through the air. The faster the bird flies, the more thrust it creates.
How Birds Flaps Their Wings
Birds flap their wings in a very specific way. They start with their wings outstretched and then bend them at the elbow. As they do this, they push their wings down and forward. This creates lift and thrust, which propels the bird forward.
Once the bird has reached a certain speed, it can stop flapping its wings and glide. When a bird glides, it simply uses the lift created by its wings to stay in the air.
How Birds Change Direction
Birds can change direction by flapping their wings in different ways. For example, if a bird wants to turn left, it will flap its left wing harder than its right wing. This creates more lift on the left side of the bird, which causes it to turn left.
Birds can also change direction by using their tails. When a bird wants to slow down, it will spread its tail out. This creates more drag, which slows the bird down.
How Birds Land
Birds land by slowing down their flight and then using their wings to create lift. As they get closer to the ground, they will often extend their legs and feet to help them stop.
The Evolution of Flight
The ability to fly is a complex adaptation that has evolved over millions of years. The earliest birds were probably small, feathered dinosaurs that lived in trees. These birds were able to glide from tree to tree, and eventually they evolved the ability to flap their wings and fly.
Over time, birds have evolved into a wide variety of shapes and sizes. Some birds are very large, such as the ostrich, while others are very small, such as the hummingbird. Despite their differences, all birds share the ability to fly, which has allowed them to colonize every continent on Earth.