Do they not see the birds
committed to fly in the atmosphere of the sky? None holds them up
in the air except God. This should be (sufficient) proof for people
who believe. (16:79)
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 can’t 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 motionless when in flight) yet flexible and
ready to swing it suddenly in any direction, bending far downward
or upward to spot prey or predators. The number of vertebrae in
a bird’s 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 coordinated. From the slow turning
of an owl’s head to the flash of a heron catching a fish,
it’s 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 center of the bird. At that
center 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 bird’s 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 bird’s 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. (67:19)
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 maneuver, slow down, change direction suddenly
and land gracefully.
The feather is a unique and wonderful creation. It’s light
yet sturdy, flexible, versatile and easy to care for, provides cushioning,
thermal insulation, and is water repellent and replaceable. Bright
colored feathers are important in some bird species for attracting
a mate and territorial displays. Some birds have feathers camouflaged
like their surroundings to help them hide.
The simple looking feather is actually a very complex mechanism.
There is a center shaft attached to the skin. From this project
many parallel branches or barbs which in turn bear smaller barbules,
which are equipped with hooks and barbs. All of these barbs catch
in one another like little zippers forming a smooth surface. If
the feather is ruffled and the connection broken, it’s easily
smoothed out and rehooked. 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.
Continued on page 4