For those of us who love birdwatching, the sight of birds flying across the blue sky is simply wonderful! Watching birds twist, glide, turn, soar, dive, etc., is truly fascinating.
Flying is not a hobby for birds, instead is an essential means of getting food and escaping danger. It also enables them to migrate long distances, and escape harsh winter months.
Although we love spending lots of time watching birds fly, have we ever wondered how they actually fly? What is it that allows only birds and no other animal to defy gravity? Let's take a look!
Before we get into the actual process by which birds fly, we need to understand that a bird's body has been specially designed for flight. Birds are lightweight, due to their fewer and hollow bones, which enable them to lift off from the ground. Moreover, the feathers blanketing the skin also play a crucial role in their ability to fly. They not only catch air, but also give shape to the bird's wings. The wings are hinged, thereby allowing the birds to fold and extend their wings as desired. Moreover, the tail is used like a rudder in a ship, and helps it maintain balance and turn when required. It also helps the bird slow down and land. Hence, we see how fearfully and wonderfully birds are made! These unique features are absent in animals, which is why only birds have the ability to fly.
Learning to Fly
Several cartoons show how the mommy bird teaches her nestlings to fly. Even in the natural world, parent birds teach their young ones to fly, by staying at a short distance away from the nest during feeding time. To eat and survive the nestling will have to step away from the nest and take the first major step of flying on his or her own. They fail miserably in the first few tries and hit their bottoms on the hard ground. However, even the falling teaches the nestling more about the mechanics of flying. The nestling learns that by stretching his or her wings, the impact of the fall can be controlled. Gradually, the short hops back to the nest turn into longer flights. The parent birds encourage their fledglings to leave the nest for longer hours. Eventually, these fledglings develop their flying skills.
How Do Birds Fly
By simple observation, we can say that birds use their wings in a flapping motion to fly in the sky. However, there's more to flying than this mere fact. As the bird flaps its wings using the strong breast muscles to fly, the feathers on the wings act like propellers and provide thrust for flying. The bird moves forward and begins flapping his or her wings. During this flapping, the pressure created over the top of the wing is lower than the pressure created under the wing. This pressure difference results in lift. Similarly, when they want to land, they spread their tails, lower their feet, and push their bodies onto the ground. So, this was all about lifting off, thrusting, and landing.
When we see a bird soaring or gliding in the sky (without flapping), what happens is that the air is being pushed down by the wings. This downward push, in accordance to Newton's third law will push the bird up. A part of the push also comes from the angle at which the wings are held, and also from their curvature. All these factors enable the bird to fly. The hummingbird exhibits unique flying styles. It can fly in one place for a long period of time with its body upright and wings sweeping back and forth like a helicopter.
Why and How do Birds Fly in a 'V' Shape?
We often find birds flying together and wonder why they fly in formations of V's. Scientists studying bird formations believe that the V-formation reduces the drag force (frictional force between two surfaces) experienced by each bird as they would if they were flying alone. Some studies have shown that a flock of 25 birds in V-formation, can fly 70% further than a bird could do on its own with the same amount of energy.
Moreover, by spacing themselves apart properly during the formation of a V while flying, the birds can optimize the reduction of drag experienced by every bird in the formation. However, the formation V does not benefit all birds equally, instead the bird in the lead position works the hardest. After all, who said being a leader is child's play! The next point will certainly interest you. When the bird at the lead position tires out, it will fall further back into one of the lines of V, and will be replaced by another bird from further back.
The two birds flying at the extreme ends of the V also get tired faster than those in the middle, so the positions keep rotating among the birds. This rotating and cyclic arrangement between the birds gives all birds the chance to become the leader and be responsible as well as remain in the middle and enjoy the comfort. What teamwork! Simply stupendous! We need to learn from these birds! The V-formation also helps the birds have a better view of each other and enables to spot any missing bird, thereby preventing them from losing any member of the flock.
Birds mostly fly below a height of 500 feet on a daily basis, whereas during migration they fly higher, at about 10,000 feet. Flying is what birds were created to do, so please refrain from buying birds and keeping them in cages. Let them fly around and live their life to the fullest. Clipping their wings and caging them is simply taking their life away.