How Do Birds Fly?

Ever wondered how birds fly?

“Yeah, sure!” you might say, “that’s a real stupid question… they flap their wings, of course!”

Yes, of course, duh! They have wings…but so does a chicken, an ostrich, a kakapo and a kiwi. Chickens love to flap their wings! But they don’t fly…?! (Kakapo are also known as “owl parrots” Read more about them here.)

Yeah, yeah, I hear you, they are flightless birds. Some of you might say they’re too big, too heavy or something to that effect.

Yet even these flightless birds all have feathers and they all have wings. Have you ever taken a single feather and thrown it up in the air? Did you notice how it naturally floats back down to the ground?

Big or small, all birds have lots of feathers, and muscles, and bones. In other words, they add even more weight to those feathers. Logically speaking, more weight equals faster falling and not flying higher, right? (We won’t be discussing the mechanical flying abilities of a 747 or Cessna here…)

 

So nothing I’ve mentioned so far have answered the question: How do birds fly?

Let’s take a closer look at two birds, a big one and a small one. Shall we?

 

A FEW INTERESTING FACTS

 

THE GREAT BUSTARD

The largest flying birds in the world are sadly still on the Vulnerable and Threatened Species List – the Great Bustard.

Great Bustards look very similar to ostriches, yet their young begins to develop their flying skills when they’re about two months old. The males can grow up to a standing height of just over a meter and weigh around 16-18 kg, although the heaviest Great Bustard on record weighed in at a whopping 21 kg!

 

 

Now that we’ve had a look at the largest flying bird, let’s take a look at a lightweight bird with amazing flying abilities.

 

HUMMINGBIRDS

One of the tiniest (flying) birds in the world is the Bee hummingbird. Yep, you guessed it – it’s scarcely bigger than a bee with a weight of around 1.6-1.8 g, their eggs are as small as seeds!

These cute little birds are usually only found in Cuba and are now listed as NT on the Threatened and Endangered List ( Near Threatened). For the usual reason – loss of habitat due to forests being converted to farmlands.

Did you know that hummingbirds got their name from the noise their fast-flapping wings make? For more interesting tidbits about hummingbirds, read more about hummingbirds here.

When a hummingbird flies forward, it can reach a speed of just over 48 km/h. They double that speed when diving, often reaching speeds of up to 96.6 km/h – that’s impressive! But even more impressive is that its short tail acts as a brake, enabling it to stop in mid air, no matter the speed it was diving or flying at.

Hummingbirds have astounding aerobatic flight abilities that makes them unique, with their own style of flight. Sometimes they look like mini-helicopters performing at an air-show. Hovering, flying sideways, straight up, backwards and even do somersaults as they fly between the flowers. So what makes their flying abilities and techniques so unique? How do they fly?

Well, for one thing, they are extremely lightweight since their bones are hollow. In addition, their vertebrae and pelvic bones are fused, their pectoral muscles are much larger, their hearts are enlarged and their feet are way too weak to walk with. Phew! Now that takes the meaning of lightweight to a totally new level for me!

 

SO HOW DO BIRDS FLY?

 

On a much more serious note, this is actually a very important question most bird owners and breeders should know the answer to. Understanding how our birds fly can actually help us to be better birders, as we’ll be able to understand our birds and their needs so much better.

For the general bird owner and (some) breeders, the required minimum size of the aviary vs the size of the bird is usually an indication of the bird’s flying habits and needs. Although any birder with the intention of keeping a specific bird should always find out as much as they can about it in advance. Please, please do not ever keep an active bird in a too small cage or aviary!

 

There are several factors affecting a bird’s flight ability, including:

  • structure of the bird’s body
  • behavior of the species
  • weather and air conditions
  • shape and movement of the wings
  • feathers, beak and legs

 

Another important point to remember is to minimize any flying hazards inside the aviary, whether the bird(s) kept inside love to fly around or not. Obviously, a more active bird will also need even more readily available, nutritious and healthy foods to fuel its activities.

 

HOW DO BIRDS FLY? AERODYNAMICS

 

The size and shape of the wings directly affect aerodynamics, namely speed, maneuverability, hovering, gliding, etc.

Even the feathers play a role in the aerodynamics because of its shape and its exact positioning on the bird’s body. Feathers actually help the bird to fly by adjusting the airflow around the bird’s wings and body. Tail feathers especially are important for steering and most birds use it like a rudder.

Flying higher or lower is achieved by manipulating the air pressure, mainly due to the thicker front part of the wing, and bigger curve over the top of the wing. To go forward and upwards, the bird creates the necessary thrust by flapping its wings, basically pushing itself through the air. To get a better idea, compare it to how a swimmer’s shoulders, arms and even hands move and change as he pushes through the water.

Last but not the least, the bird’s beak and legs also play an important role in its flight abilities. Once again, the extent to which the legs affect the flying is mainly dependent on the species. Leg power is especially important to those birds who need to jump into flight. Or those who need to build up speed like a plane taking off…

As far as the bill is concerned, I think that’s quite self-explanatory. Pointy beaks assist by slicing through the air, assisting the rest of the bird’s body to reduce friction in the air.

 

BODY STRUCTURE

 

If a bird is meant to fly, it’ll fly. If not? It’s either sick, hurt or a member of the exclusive little group of flightless birds… Frankly, flightless birds don’t fly because their bodies are not designed or created to fly. It’s as simple as that. A bird uses its whole body when it’s flying.

To assist the bird in its flight, its body’s weight is reduced in various ways, depending on each species of birds. Whether this is accomplished by hollow bones or air hollows in the skeletal structure, a reduction of the organs it needs or more muscles wherever its needed.

Since birds have a higher metabolic rate, they digest food more quickly to have the energy they need for flying. It’s rare to near impossible to find an obese bird in the wild!

Size of the feet is also important as some birds tuck their legs and/or feet up while flying. Some birds, like the humming bird’s feet are nothing but tools to keep them upright in a standing position or holding on to a perch. They can’t walk or perch like parrots, but they do fly SO much better than any parrot!

 

WEATHER AND AIR CONDITIONS

 

Birds are designed and equipped to be excellent fliers, well…excluding the flightless ones of course! But birds are also masters of taking advantage of the weather and other air conditions.

Have you ever seen a bird flying in strong or gusty winds? One can learn a lot about the way pigeons fly by watching them fly on windy days. The way they face the winds, maneuvering their bodies and wings – it’s an awe-inspiring sight!

And of course we’ve all seen footage or heard about the eagles soaring above the storms, using those strong winds to fuel their flight, etc. Wind, air currents and even the temperature of the air are utilized by a bird in flight.

Something else of interest is that the sensitive skin of a bird allows it to notice even the slightest change in the air. They will then immediately adapt their flight to allow them to fly more easily in those specific air conditions.

 

 

Browse through this gallery with a few pictures of our feathered friends. Take note of the feather positioning, wing movements, leg and feet positions and the overall body structure of the various birds.

(Click on the image below to view the gallery.)

 

 

IN CONCLUSION

In this article I endeavored to bring another aspect of bird keeping to your attention, an overview and not an in-depth discussion. If you have any more questions, do some research or discuss with your avian vet.

So…in conclusion. That old argument that flightless birds don’t fly because they’re too big or heavy is kind of moot. Birds meant to fly are designed to fly. And they have all the necessary ‘equipment’ and adaptations to assist them in their flight.

 

PS.

Come to think of it, a 3 month old baby ostrich roughly weighs around 30 kg. What if someone were to use some feathers and design a flappable pair of wings relative in size to a 25 kg bag of sunflower seed. If they then connect it to a remote control before attaching those wings to the bag of seed, I suppose the ‘winged bag’ will at least be able to flap it’s wings? But the real question will be – Can that 25 kg winged bag fly?! Mm…

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