Wouldn’t it be great if we could all fly? Flight has always been a magical and refreshing thought for humankind. Some creatures are simply born to fly and are adapted so well for flight that we can’t help but feel jealous of them. It would be a dream come true if we could fly like dragons… I mean birds, but it’s a bit out of our reach.
But birds are masters of flight, and we’ve been admiring them as they soar above us for thousands and thousands of years. Let’s take a look at what it is about birds that enable them to fly so high above the world below (and occasionally dropping their business on our shoulders).
Anatomy Suited For Flight
First of all, it’s important to note that birds are very lightweight – extremely light, in fact. Most of the evolutionary changes they’ve gone through has been to make them lighter. They have special bones, for instance, which are basically hollow. The insides of their bones contain air sacs and tiny cross-linkages similar to the structure of a honeycomb. This makes them light, but also extremely strong.
Birds also have very light feathers, so they aren’t weighed down by these important features, despite having so many of them. Birds also have no teeth and fewer organs than most animals. Another way that birds have adapted for flight is by having large, strong breast muscles that are attached to an enlarged sternum (breastbone).
Also, perhaps most importantly, birds have wings and bodies that are streamlined (reducing drag or air resistance).
The Physics Of Flight
When a bird is in flight, wind quickly rushes over the top surface of their wings (due to the top having a greater surface area). Therefore, wind takes longer to pass under the wing, producing the necessary lift for flight.
Flapping their wings is also an (obviously) integral aspect to the flight of birds.
As the bird beats its wings down, air acts on it in two ways: it propels the bird forward (providing thrust) and keeps it in the air. The trick of flapping their wings comes into play when they go back up. During this phase, the wings are bent, thereby reducing the air acting on it, and preventing the bird from being pushed down.
Air currents are excellent for birds, as they can easily soar and glide on these currents, expending little to no energy. The bird simply spreads its wings out and tilts itself at a slight angle, in order to deflect air downwards. It also tilts itself forward when the drag force increases.
With all of these specific adaptations that make birds fit for flight, it’s no wonder that these graceful creatures soar across our skies, looking effortless and free. I only have one more warning about flight: Don’t try it at home!
- Bird Flight – Wikipedia
- Adaptations for Flight – Stanford University
- How Do Birds Fly? – Ask A Biologist (Arizona State University)