Birds: Structure and Flight courtesy of IFSA
they not see the birds committed to fly in the atmosphere of the sky? None holds
them up in
the air except Allah. This should be (sufficient) proof for people who believeĒ. (Quran16:79)
That birds can fly and so efficiently is miraculous. In order to work, such a
flying machine must be amazingly lightweight and yet incredibly tough and strong. To take off and
maintain flight, the bird canít be too heavy. Yet to survive the conditions faced in the air and the
force of landing, it must be tough so as not to break
on impact. These two qualities (lightness and toughness) are exactly how a bird is constructed.
The skeletal framework of a bird is rigidly interconnected with a very sturdy spinal column of fused vertebrae. The neck is strong but incredibly flexible as it must have the strength to support the head (keeping it motion-less when in flight) yet flexible and ready to swing it suddenly in any direction, bending far downward or up-ward to spot prey or predators. The number of vertebrae in a birdís neck varies from long-necked to short-necked birds.
This may sound obvious. But a mouse has the same number of cervical vertebrae as a giraffe (seven). Birds have a minimum of 11. Flexibility of the neck is achieved by a system of long bands of muscles and smaller muscles that are perfectly co-ordinated. From the slow turning of an owlís head to the flash of a heron catching a fish, itís a masterful machine.
Bones in the bird are hollow and thin-walled for lightness with internal struts for support. All weight is concentrated toward the centre of the bird. At that centre is a very large breastbone to which are attached the pectoral muscles, the mighty muscles which drive the wings. Flight muscles may account for 25-30 percent of a birdís weight, compared to pectoral muscles in the human which weigh less than one percent of total weight. These muscles working to drive the wings build up great heat. To counteract this, the bird has the most efficient respiratory system of any vertebrate. Rather than a single pair of lungs the bird
has a system of air sacs throughout the body even in some of the hollow spaces in the bones. The air is taken in quickly to all important parts of the body and the birdís faster heartbeat provides rapid circulation.
Good eyesight is an important prerequisite of flight. A bird relies more heavily on vision than most animals. In some birds their eyes actually weigh more than their brains. Birds can see distant things as much as eight times more clearly than man can, and they also see close up much better. Most birds have both monocular and binocular vision. They can rely on what one eye sees close up and then count on sharper binocular vision for distances.
"Have they not seen the birds above them lined up in columns and spreading their wings? The Most Gracious is the One who holds them in the air. He is Seer of all things." (Quran 67:19)
Wings and Feathers
Most important to flight are the wings and feathers. The wing is really an arm with a large ball joint fitting into the socket in the shoulder. This is a specialized joint allowing great mobility. The way the bird can rotate as well as flap up and down gives the bird the ability to manoeuvre, slow down, change direction suddenly and land gracefully.
feather is a unique and wonderful creation. Itís light yet sturdy, flexible,
versatile and easy to care for, provides cushioning, thermal insulation, and is water repellent and replaceable.
coloured feathers are important in some bird species for attracting a mate and for territorial
displays. Some birds have feathers
camouflaged like their surroundings to help them hide. are equipped with hooks and barbs. All of these
the wing at the shoulder, can twist the
Gulls also have the instinct to use obstacles,
The simple looking feather is actually a very complex mechanism. There is a centre shaft attached to the skin. From this project many parallel branches or barbs which in turn bear smaller barbules, which
With all the bird does, there is continuous wear and tear on the feathers, so they must be replaceable. Thatís why birds malt on a regular basis. Malting is a precise process, triggered in the least severe season. The feathers are discarded usually in pairs (one from the right side and the corresponding one from the left). And never so many that the bird canít fly, although it may be weakened. To compensate, new feathers grow in very fast.
None holds the birds in the air except Allah.
Allah holds them in the air. Allah gives them the physical construction to fly, the use of wings. They can raise and lower the wings, can move them for-ward or back, they can reduce the wing area, can
Hummingbirds can fly backwards. Penguins, who donít fly, use their wings like a powerful oar to move quickly through the water. Hawks can turn upside down in full flight to catch smaller birds trying to escape, then right themselves and fly on without missing a beat.
Birds use the wind with great skill, as if they studied science. Some birds use land drafts to soar and glide, like an eagle using the currents in a canyon. Over water, seabirds are incredibly adept at using
are equipped with hooks and barbs. All of thesebarbs catch in one another like little zippers forming a smooth surface. If the feather is ruffled and the connection broken, itís easily smoothed out and re-hooked. On each feather there are millions of these barbules hooking the feather together. When the wings are folded the feathers lie over one another like roof shingles with air spaces between to insulate against heat loss.
rotate the wing at the shoulder, can twist thewings. Then Allah gives them the instincts to know how to do it. Birds donít study the laws of gravity but they use them. From great heights, theyíll tuck their wings and fall straight down, then pull out the wings to provide resistance to slow down and land. They make it look easy.
drafts. Gulls also have the instinct to use obstacles,like ships, which create extra updrafts. Theyíll follow motionless, looking as if theyíre tied like a kite on a string.
|Back to Spiral Galaxy||
Last updated on 31/10/2002