Birds make flying look easy. That’s because they were built for flight. In fact, the Wright brothers spent a lot of time studying birds flying before flying the first successful airplane.
So how do birds fly? The short answer is with their wings, but there’s a lot more to it than that. Birds have many special features besides their wings that help them fly. Their bones are hollow, making them lightweight for flight. Their feathers are also lightweight and help them catch air while flying.
Birds also breathe differently than people, and that helps them fly long distances without getting tired. Birds need a lot of oxygen to fly, and their lungs work well to pull all of the oxygen out of the air they breathe.
Even laying eggs instead of giving birth to live babies, like mammals, helps birds fly. Laying their eggs in nests allows the female birds to remain lightweight while their babies develop outside their bodies.
The basics of flight involve four steps:
Taking off
Staying in flight
Directing themselves in flight
Landing safely
The special shape of a bird’s wings helps them take off. Air moves over and under their wings at takeoff. The air above the wings moves faster than the air below. This creates lift, allowing the bird to take off.
After taking off, birds have to stay in the air. They can do this by soaring or flapping. When birds soar, they use air currents, drafts and wind to stay high in the sky. Flapping their wings also helps them stay in the air. With each stroke, the wing tips move forward and down. Then as the wings move up, the tips go up and back. This motion creatures lift because of the differences in air pressure above and below the wings. Some birds are more flappers, while others are more soarers. Birds that flap typically have smaller wings than birds that soar.
How birds change direction in flight is different for birds that soar than birds that flap their wings. When birds soar, they fly in a circular direction because of the air currents and drafts. These birds make very slight adjustments to turn themselves in the direction they want to travel. Flapping birds can direct themselves in flight by turning in the direction they want to go.
When a bird needs to land, they use their wings both to slow down and lower themselves toward their landing spot. Some birds have to slow down for longer than others to land safely, while others can land very quickly. Birds like ducks and geese outstretch both their wings and feet to help them slow down.
Of course, not all birds fly. Penguins don’t, and neither do ostriches, emus and several other birds. So why not? Scientists don’t entirely understand why. In the case of ostriches and emus, they believe these birds evolved through the years, making them unable to fly.
Penguins, though, are a different story. They are good swimmers. Researchers believe birds cannot be both good swimmers and flyers because muscles needed for flight become weaker as the animals become accustomed to diving into the water.