CHAPTER 2

Flawless Flying Machines: Birds

Because they believe that the birds must have somehow evolved, evolutionists assert that birds are descendants of reptiles. However, the progressive model of evolution cannot explain any of the body mechanisms of birds, which have a completely different structure from mammals. First, the primary feature of birds, i.e. wings, is a great obstacle for the theory of evolution to explain. One of the Turkish evolutionists, Engin Korur, makes the following confession in reference to the impossibility of the evolution of wings:

The common trait of eyes and the wings is that they can only function if they are fully developed. In other words, a halfway-developed eye cannot see and a bird with half-formed wings cannot fly. How these organs came into being is one of those mysteries of nature that has still to be accounted for.13

The question of how the flawless structure of wings might have been formed through a series of consecutive random mutations remains completely unanswered. The process in which the front leg of a reptile could transform into a flawless wing seems to be as inexplicable as ever.

Furthermore, the existence of wings is not the only prerequisite for a land creature to become a bird. Mammals totally lack a number of mechanisms that are used by birds in flying. For example, the bones of birds are considerably lighter than those of mammals. Their lungs are of a different structure and function as well as are their skeletal and muscular structures. Their circulatory systems are much more specialised than those of mammals. All of these mechanisms could not possibly come into existence over time through an "accumulative process". Assertions of the transformation of mammals into birds are, therefore, only nonsensical claims.

Structure of Bird Feathers

The theory of evolution, which claims that birds are descendants of reptiles, is not able to explain the colossal differences between these two classes of beings. Birds display properties distinct from reptiles in having a skeletal structure composed of hollow, extremely lightweight bones, and a unique respiratory system and in being warm-blooded creatures. Another structure unique to birds, which places an unbridgeable gap between birds and reptiles, is the feather.

Feathers are the most important of the interesting aesthetical aspects of birds. The phrase "light as a feather" depicts the perfection in the intricate structure of a feather.

Feathers are constructed of a protein substance called keratin. Keratin is a hard and durable material that is formed by the old cells that migrate away from the nutrient and oxygen sources in the deeper layers of the skin and die in order to give way to new cells.

The design in bird feathers is so complex that the process of evolution simply cannot explain it. Scientist Alan Feduccia says feathers "have an almost magical structural complexity" which "allows a mechanical aerodynamic refinement never achieved by other means".14 Although he is an evolutionist, Feduccia also admits that "feathers are a near-perfect adaptation for flight" because they are lightweight, strong, aedodynamically shaped, and have an intricate structure of barbs and hooks.15

The design of feathers also compelled Charles Darwin ponder them. Moreover, the perfect aesthetics of the peacock's feathers had made him "sick" (his own words). In a letter he wrote to Asa Gray on April 3, 1860, he said "I remember well the time when the thought of the eye made me cold all over, but I have got over this stage of complaint..." And then continued:

... and now trifling particulars of structure often make me very uncomfortable. The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick!16

Small Barbs and Hooklets

One encounters an incredible design if the feather of a bird is examined under the microscope. As we all know, there is a shaft that runs up the centre of the feather. Hundreds of small barbs grow on either side of this shaft. Barbs of varying softness and size give the bird its aerodynamic nature. Furthermore, each barb has thousands of even smaller strands attached to them called barbules, which cannot be observed with the naked eye. These barbules are locked together with hooklike hamuli. The barbules hold on to one another like a zip with the help of these hooklets. For example, just one crane feather has about 650 barbs on each side of the shaft. About 600 barbules branch off each of the barbs. Each one of these barbules are locked together with 390 hooklets. The hooks latch together as do the teeth on both sides of a zip. These barbules interlock so tightly that even smoke blown at the feather cannot penetrate through it. If the hooklets come apart for any reason, the bird can easily restore the feathers to their original form by either shaking itself or by straightening its feathers out with its beak.

In order to survive, birds have to keep their feathers clean, well-groomed and always ready for flight. They use an oil-gland located at the base of their tails for the maintenance of their feathers. They clean and polish their feathers by means of this oil, which also provides water proofing when they are swimming, diving or walking and flying in rain.

In addition, in cold weather the feathers prevent the body temperature of birds from falling. The feathers are pressed closer to the body in hot weather in order to keep it cool.17

Feathers spring from a hollow cylindrical structure of the skin.

A chick that is 2-3 hours old primarily has feathers for warmth.

Types of Feather

Feathers take on different functions depending on where on the body they are located. The feathers on a bird's body have different properties from those on the wings or tail. The full-feathered tail functions to steer and brake. On the other hand, wing feathers have a distinct structure that enables the surface area to expand during beating in order to increase forces of up-lift. When the wing is flapped downward, the feathers come closer together, preventing the through passage of air. When the wing is in an upward movement the feathers open up, to give way to the passage of air.18 Birds shed their feathers during certain periods in order to maintain their abilities to fly. Worn or damaged large feathers are renewed immediately.

This serial motion depicts various phases in a sparrow's flight: take-off, short flight and landing. Due to the curvature of the wing, air pressure on the upper surface is weaker than on the under surface, which in turn lifts the bird into the air (bottom left). If the wing is curved, further airflow at the top increases the pressure creating a downward force. This way the bird stalls (right bottom). The wing of a goatsucker Yellow lines indicate the curvature of the wing. The wing of a falcon Old feathers of birds are replaced with new ones with different frequencies in different species. The renewal of feathers is called moulting, which happens before migration.

FEATURES OF THE FLYING MACHINES

A close examination of birds reveals that they are designed specifically for flying. The body has been created with air-sacs and hollow bones in order to reduce body mass and overall weight. The fluid nature of their wastes ensures that excess water in the body is disposed of. Feathers are extremely light structures in comparison to their volume.

Let us examine these special structures of birds one by one:

1- The skeleton

The strength of a bird's skeleton is more than adequate even though the bones are hollow. For example, a hawfinch 7 inches long (18 cm) exerts about 151 lbs. (68.5 kg) pressure in order to crack open an olive seed. Better "organised" than mammals, the shoulder, hip and chest bones of birds are fused together. This design improves the strength of the bird's structure. Another feature of the skeleton of birds, as mentioned previously, is that it is lighter than in all other mammals. For instance, the skeleton of the dove weighs only about 4.4% of its total body weight. The bones of the frigate bird weigh 118 gr, which is less than the total weight of its feathers.

Bird bones are extremely light but sturdy, largely because they are hollow. There is air inside the cavities where supporting bars stiffen the bones. These hollow bones are the main inspirations for the design of modern aeroplane wings.

2- Respiratory System

The respiratory system of mammals and birds operate on completely different principles, primarily because birds need oxygen in much greater quantities than do mammals. For example, a certain bird could require up to twenty times the amount of oxygen necessary for humans. Therefore, the lungs of mammals cannot provide oxygen in the quantities required by birds. This is why the lungs of birds are created upon a much different design.

In mammals, air flow is bidirectional: air travels through a network of channels, and stops at the small air sacs. Oxygen-carbon dioxide exchange takes place here. Used air follows a reverse course in leaving the lung and is discharged through the windpipe.

THE SPECIAL LUNGS OF BIRDS Birds have a very different anatomy from their alleged ancestors, the reptiles. Bird lungs operate in a completely different fashion from those of mammals. Mammals inhale and exhale air through the same windpipe. In birds, however, the air enters and exits through opposite ends. A special "design" such as this has been created to provide for the high volumes of air needed during flight. Evolution of such a structure from that of reptiles is not possible.

On contrary, in birds, air flow is unidirectional. New air comes in one end, and the used air goes out the other end. This provides an uninterrupted supply of oxygen for birds, which satisfies their need for high levels of energy. Michael Denton, an Australian biochemist and a well-known critic of Darwinism, explains the avian lung in this way:

Unidirectional airflow in the bird's lungs is facilitated by a system of air-sacs. These sacs collect air and then pump it regularly into the lung. In this way, there is always fresh air in the lungs. A complex respiratory system such as this has been created to satisfy birds' needs for high quantities of oxygen.

In the case of birds, the major bronchi break down into tiny tubes which permeate the lung tissue. These so-called parabronchi eventually join up together again, forming a true circulatory system so that air flows in one direction through the lungs…. Although air sacs occur in certain reptilian groups, the structure of the lung in birds and the overall functioning of the respiratory system is quite unique. No lung in any other vertebrate species is known which in any way approaches the avian system. Moreover, it is identical in all essential details in birds…19

In his book A Theory in Crisis, Michael Denton also points out to the impossibility of formation of such a perfect system through progressive evolution:

Just how such an utterly different respiratory system could have evolved gradually from the standard vertebrate design is fantastically difficult to envisage, especially bearing in mind that the maintenance of respiratory function is absolutely vital to the life of an organism to the extent that the slightest malfunction leads to death within minutes. Just as the feather cannot function as an organ of flight until the hooks and barbules are coadapted to fit together perfectly, so the avian lung cannot function as an organ of respiration until the parabronchi system which permeates it and the air sac system which guarantees the parabronchi their air supply are both highly developed and able to function together in a perfectly integrated manner.20

In short, the transition from mammal lung to avian lung is impossible due to the fact that the lung that would be in a transitional developmental stage would have no functionality. No creature without lungs can live for even a few minutes. Therefore, the creature simply would not have millions of years to wait for random mutations to save its life.

The unique structure of the avian lung demonstrates the presence of a perfect design that supplies the high levels of oxygen required for flight. It only takes a little bit of a common sense to see that the unparalleled anatomy of birds is not an arbitrary result of unconscious mutations. It is clear that the lungs of a bird are another of the countless evidences that all creatures have been created by God.

3-The System of Balance

God has created birds without flaw just as He has the rest of the creation. This fact is manifest in every detail. The bodies of birds have been created to a special design that removes any possible imbalance in flight. The bird's head has been deliberately created light in weight so that the animal does not lean forward during flight: on average, a bird's head weight is about 1% of its body weight.

The aerodynamic structure of the feathers is another property of the system of balance in birds. The feathers, especially in the wing and tail, provide a very effective system of balance for the bird.

These features ensure that a falcon maintains absolute balance while diving for its prey at a speed of 240 mph (384 km/h).

4- The Power and Energy Problem

Every process in the form of a sequence of events, i.e. in biology, chemistry or physics, conforms to the "Principle of the Conservation of Energy". In short, one can summarise this as "it takes a certain amount of energy to get a certain work done".

A significant example of this conservation can be observed in flight of birds. Migrating birds have to store enough energy to take them through their trip. On the other hand, another necessity in flight is being as light as possible. No matter what the results, extra weight has to be done away with. In the meantime, the fuel has also to be as efficient as possible. In other words, while the weight of fuel has to be at a minimum, the energy output from it has to be at a maximum. All of these problems have been solved for birds.

The first step is to determine the optimum speed for flight. If the bird is to fly very slowly, then a lot of energy has to be spent to remain aloft in the air. If the bird is to fly very fast, then fuel will be spent in overcoming air resistance. It is therefore obvious that an ideal speed has to be maintained in order to spend the least amount of fuel. Depending on the aerodynamic structure of the skeleton and wings, a different speed is ideal for each kind of bird.

Let us examine this energy problem as it relates to the Pacific golden plover (Pluvialis dominica fulva): this bird migrates from Alaska to Hawaii to spend its winters there. There are no islands on its route. Therefore, it has no possibility for rest. The flight is 2500 miles (4000 km) from start to finish and this roughly means 250,000 wing beats without break. The trip takes more than 88 hours.

The bird weighs 7 ounces (200g) at the start of the journey, 2,5 ounces (70g) of which is fat to be used as fuel. However, scientists, after calculating the amount of energy the bird needs for an hour of flight, determined that the bird needed 3 ounces (82g) of fuel for this flight. That is, there is a shortage of 0.4 ounce (12g) of fuel and the bird would have to run out of energy hundreds of miles before reaching Hawaii.

In spite of these calculations, the golden rain birds unfailingly reach Hawaii every year. What could the secret of these creatures be?

Birds prefer to travel in flocks on long trips. The "V" formation of the flock enables each individual bird to save about 23% energy.

The Creator of these birds, God, inspires them with a method to make their flight easy and efficient. The birds do not fly haphazardly but in a flock. They follow a certain order and form a "V" shape in the air. This V formation reduces the air resistance that they encounter. This flight formation is so efficient that they save about 23% of their energy. This is how they still have 0.2 ounces (6-7g) of fat when they land. The extra fat is not a miscalculation but a cushion to be used in case of encountering reverse air currents.21

This extraordinary situation brings the following questions to mind:

How could the bird know how much fat is needed?

How could the bird manage to acquire all this fat before flight?

How could it calculate the distance and the amount of fuel it needs to burn?

How could the bird know that conditions in Hawaii are better than Alaska?

It is impossible for birds to reach this knowledge, to make these calculations, or to make group flights according to these calculations. This is an indication that the birds are "inspired" and directed by a superior power.

5. Digestion System

Flight requires a great deal of power. For this reason birds have the largest muscle-tissue/body-mass ratio of all creatures. Their metabolism is also in tune with high levels of muscle power. On average, a creature's metabolism doubles as the body temperature increases by 50°F (10°C). The sparrow's 108°F (42°C) body temperature and a fieldfare's 109.4°F (43.5°C)body temperature indicate how quickly their metabolism functions. Such a high body temperature, which would kill a land creature, is vitally important for a bird's survival by increasing energy consumption and, therefore, power.

Due to their need for a lot of energy, birds also have a body that digests the food they eat in an optimum fashion. Birds' digestive systems enable them to make the best use of the food they eat. For example, a baby stork puts on 2.2 lbs (1 kg) body mass for every 6.6 lbs (3 kg) food. In mammals with similar food choices, this ratio is about 2.2 lbs (1 kg) to 22 lbs. (10 kg). The circulatory system of birds has also been created in harmony with their high energy requirements. While a human's heart beats 78 times a minute, this rate is 460 for a sparrow and 615 for a humming bird. Similarly, blood circulation in birds is very fast. The oxygen that supplies all of these fast working systems is provided by special avian lungs.

The sparrow's heart beats 460 times per minute. Its body temperature is 108°F (42°C). Such a high body temperature, which would mean certain death for a land creature, is vitally important for a bird's survival. The high level of energy birds require for flight is generated by this rapid metabolism.

Birds also use their energy very efficiently. They demonstrate significantly higher efficiency in energy consumption than do mammals. For instance, a migrating swallow burns four kilocalories per mile (2.5 per kilometre) whereas a small mammal would burn 41 kilocalories.

Mutation cannot explain the differences between birds and mammals. Even if we assume one of these features to occur through random mutation, which is not a possibility, a single feature by itself does not make any sense. The formation of a high energy-producing metabolism has no meaning without specialised avian lungs.

A swallow

Moreover, this would cause the animal to choke from insufficient oxygen intake. If the respiratory system were to mutate before the other systems then the creature would inhale more oxygen than it needs, and would be harmed just the same. Another impossibility relates to the skeletal structure: even if the bird somehow obtained the avian lungs and metabolic adaptations it still could not fly. No matter how powerful, no land creature can take off from the ground due to its heavy and relatively segmented skeletal structure. The formation of wings also requires a distinct and flawless "design".

All of these facts take us to one result: it is simply impossible to explain the origin of birds through accidental growth or a theory of evolution. Thousands of different species of birds have been created with all their current
physical features in "a moment". In other words, God has created them individually.

PERFECT FLIGHT TECHNIQUES

From albatrosses to vultures, all birds have been created equipped with flying techniques that make use of winds.

Since flying consumes a lot of energy, birds have been created with powerful breast muscles, large hearts and light skeletons. The evidence of superior creation in birds does not end with their bodies. Many birds have been inspired to use methods that decrease the energy required.

The kestrel is a wild bird that is well-known in Europe, Asia and Africa. It has a special ability: it can maintain its head in a perfectly still position in the air by facing the wind. Though its body may sway in the wind, its head remains motionless, which increases the excellence of its vision in spite of all the motion. A gyroscope, which is used to stabilise the weaponry of battleships at sea, works very similarly. This is why scientists usually label the bird's head "a gyro-stabilised head".22

Timing Techniques

Birds regulate their hunting schedules for optimum efficiency. Kestrels like to feed on rats. Rats typically live underground and surface every two hours to feed. Kestrels' feeding coincides with the rats'. They hunt during the day but eat their kill at night. Therefore, during the day, they fly on empty stomachs with less weight. This method cuts down the energy required. It has been calculated that the bird saves about 7% energy this way.23

Soaring in the Wind

Birds further reduce the energy consumed by utilising winds. They soar by increasing airflow on their wings and they can remain "suspended" in sufficiently powerful air currents. Up-drafts are an added advantage to them.

Making use of air currents in order to save energy in flight is called "soaring". The kestrel is one of the birds with this capability. The ability to soar is a sign of birds' superiority in the air.

Soaring has two major benefits. Firstly, it conserves energy needed to stay in the air while searching for food or defending the feeding ground. Secondly, it enables the bird to significantly increase its flight distances. A seagull can save up to 70% of its energy while soaring.24

Energy from Air Currents

Birds use air streams in different ways: A kestrel gliding down a hillside or a seagull diving along coastal cliffs make use of airstreams, and this is called "slope soaring".

When a strong wind passes over a hilltop, it forms waves of motionless air. Birds can soar on these waves as well. The gannet and many other seabirds make use of these motionless waves created by islands. Sometimes they use the currents generated by smaller obstacles such as ships, over which seagulls soar.

Fronts generally create the currents providing uplift for birds.

Fronts are interfaces between air masses of different temperatures or densities. The soaring of birds on these interfaces is referred to as "gust gliding". These fronts, which are especially formed at coasts by air currents coming from the sea, have been discovered by means of radar, through the observation of sea birds in flocks gliding in them. Two other kinds of soaring are known as thermal soaring and dynamic soaring.

Thermal soaring is a phenomenon observed especially in warm inland areas of the globe. As the sun heats the ground, the ground in turn heats the air above it. As the air gets warmer, it gets lighter and starts to rise. This event can also be observed in dust storms or other wind whirls.

The Soaring Technique of Vultures

Vultures utilise a special method in order to scan the earth below from an appropriate height riding rising columns of warm air, called the thermals. They can continuously make use of different thermals to sustain their soaring over very large areas for very long times.

At dawn, airwaves start rising. First, smaller vultures take off, riding weaker currents. As currents become stronger, larger birds take off as well. Vultures almost float upward in these ascending currents. The fastest rising air is located in the middle of the current. They fly in tight circles in order to balance uplift with gravitational forces. When they want to ascend, they draw closer to the centre of the currents.

Vultures can reach their food before their rivals, the hyenas, due to their flight techniques. In the figure above, the griffon vulture feeding on a carcass catches the attention of a lappet-faced vulture and a hyena. However, even the hyena's highest speed of 25 mph (40 km/h) is not enough to reach the carcass in time. The hyena can reach a carcass 2.2 miles away (3.5 kilometres) in 4.25 minutes whereas the lappet-faced vulture reaches the carcass in three minutes at a speed of 44 mph (70 km/h).

Other hunting birds use thermals as well. Storks make use of these warm air currents, especially when migrating. The white stork lives in central Europe and migrates to Africa for winters on a journey of about 4350 miles (7000 kilometres). If they were to fly solely by flapping their wings, they would have to rest at least four times. Instead, the white storks complete their flights in three weeks by utilising warm air currents for up to 6-7 hours a day, which translates into big energy savings.

Since the waters warm up much later than the land, warm air currents are not formed over the seas, which is why birds that migrate over long distances do not choose to travel over water. Storks and other wild birds migrating from Europe to Africa choose to travel either over the Balkans and the Bosphorus, or over the Iberian Peninsula over the Gibraltar.

The skimmer lacks oil protecting its feathers from water. Therefore, it does not dive for its prey. Its lower bill is longer and sensitive to touch. Its wings are shaped such that it can fly very close to the surface of the water for a long time without flapping its wings. It dips its lower bill in the water and flies while using this technique. It captures any prey that its lowered bill hits. Wild geese climb up to 5 miles (8 kilometres). However, at about 3.1 miles (5 kilometres), the atmosphere is 65% less dense than at sea level. A bird flying at this height has to flap its wings much faster, which would require much more oxygen. In sharp contrast to mammals, the lungs of these creatures have been created to make best use of the sparse oxygen supply at these altitudes. The albatross with a wingspan of 10 feet (3 metres) is one of the world's largest birds. Such a large body requires a lot of energy for flight. However, the albatross can fly long distances without flapping its wings by using the dynamic soaring method. This technique saves this creature tremendous amounts of energy.

The albatross, gannets, seagulls and other sea birds, on the other hand, use the air currents that are created by high waves. These birds take advantage of the uplift of air directed upwards on the tips of waves. While soaring on the air currents, the albatross frequently turns and heads into the wind and swiftly rises higher. After ascending 30-45 feet (10-15 metres) into the air, it changes direction again and continues soaring. The bird gains energy from changes in wind directions. The air currents lose speed when they hit the surface of the sea. This is why the albatross encounters stronger currents at higher altitudes. After attaining adequate speed, it returns to gliding close to the surface of the sea. Many other birds such as the shearwater use similar techniques while soaring on the sea.

The visual faculties of birds hunting during the daytime are far superior to humans. A human can see a rat in the distance as a blur without focus, whereas a falcon can see the same animal at same distance in much greater detail. Eyes located on both sides of head provide the pigeon with a very wide visual field (orange and yellow areas). The rain bird moves extremely fast with swift manoeuvres in the air, which requires an even wider visual field than most birds. Large eyes located on both sides of its head provide this field of vision. The most advanced senses of birds are vision and hearing. Birds that usually hunt by day have better visual faculties. The hearing of birds that prey at night is superior to other faculties. Some birds that hunt by diving, such as herons and cormorants, are equipped with eye structures that enable them to see effectively in water. The cornea of their eyes is flatter, which gives refraction and better vision. The eyes of most birds are located on both sides of the head. Hence, they have a wide angle of view. The frontal location of the eyes of wild birds that prey at night is another flawless design because these birds require "binocular" vision more than a wide angle view, and binocular vision (the area in which both eyes can see an object) has a narrow angle of view but more depth and focus just as does human vision. Birds have other interesting senses as well, which enable them not only to perceive vibrations in the air but also to navigate their routes by following the magnetic fields of the earth. The eyes of an owl are located to the front of its head. This design provides the bird with a superb "binocular" vision. Yet it also creates a wide blind field. This blind field is by no means disadvantageous to the bird since it can rotate its head 270 degrees and look behind itself easily. The woodpecker can easily reach larva hidden in tree trunks by its tongue. Humming birds can collect flower nectar by using their slim, forked tongues. For some birds, a keen sense of smell is vitally important. The black vulture can locate carcasses from great distances because of its advanced sense of smell.

PERFECT DESIGNS FOR FLYING, SWIMMING AND RUNNING BONES Since birds are designed for the purpose of flight, their bones are hollow and wrapped with muscles, which provide miraculous lightness without compromising strength. The skeletons of birds are designed to effectively enable them to fly, walk and even swim in the fastest and most efficient way. All flying birds are equipped with an extremely strong breastbone (sternum) which has a large flattened plate, called a keel, for the attachment of flight muscles. The muscles wrapping this bone facilitate flight. The part of the skeleton called the breast plate constitutes a very sturdy support for the wing bones, and is comprised of the breast bone and wishbone that is unique to birds. The bones that carry the wings are very long and fused together. The wing tip feathers attach to the fused "hand" bones. The pelvic girdle extends both downward and backward in order to enable the leg muscles to work more effectively. The outspread wings of the stork in the figure show the composition of its various feathers. Shorter feathers layered one on top of another give the bird aerodynamic advantages. RIB CAGE The breast bones of birds are relatively inflexible for protection of the body when the wings are closed. That is, the volume of the rib cage does not change during flight, inhalation or exhalation. "Running birds", such as the ostrich, have long legs and strong muscles that function in running, whereas predator birds have shortened bodies and relatively spinal cord sloped, which enables them to move more swiftly. The wings are pulled downward by the contracting muscles. When the wings are raised and the small breast muscles (supracoracoideus) are contracted, the large breast muscles (pectoralis major) are flexed. When the large breast muscles are contracted and the small breast muscles are flexed, the wings are lowered. Sparrows have keeled sternum that enables them to fly for extended periods. This bone is covered with breast muscles.

A night owl, with a wingspan of 21.7 inches (55 centimetres), is an ideal night hunter. Its large eyes are lodged in the front its head. This location is very advantageous in its finding its prey. Another property of its eyes is the capability for night vision. The flight of birds is a wonderful type of movement. Their speed in flight is far beyond what one could achieve by running or swimming. Furthermore, the energy spent per unit distance is also far less than in running and swimming. Humankind made a tremendous leap in flight technology in the 20th century. One of the key ingredients in this advance was the study by scientists of the designs found of the bodies of birds. In the design of aircraft, many aerodynamic principles found in birds are implemented, leading to very successful applications. This is due to the flawless creation of birds, just as in the perfection evident in the rest of the creation.

DESIGN IN BIRD EGGS

The miraculous creation of birds does not end with wings, feathers or their migration skills. Another extraordinary design feature of these creatures is in their eggs.

However ordinary it may seem to us, the egg of a chicken has about fifteen thousand pores resembling dimples on a golf ball. The spongy structure of smaller eggs can only be observed under the microscope. These spongy structures give eggs added flexibility and increase their resistance to impact.

An egg is a miracle of packaging. It supplies all the nutrients and water that the developing foetus needs. The yolk of the egg stores protein, fats, vitamins and minerals, and the white works as a reservoir of fluid.

The developing chick needs to inhale oxygen and exhale carbon dioxide. It also requires a source of heat, calcium for its bone development, protection of its fluids, protection against bacteria and physical impact. The eggshell provides all of these for the chick, which breathes
through a membranous sac that develops in the embryo. Blood vessels in this sac bring oxygen to the embryo and take carbon dioxide away.

Eggshells are amazingly thin and sturdy, and so transmit the body heat of the brooding parent.

A Necessary Loss

Section of egg

During incubation, the egg loses 16% of its water content in the form of evaporation. Scientists long believed this to be harmful and due to the porous structure of the eggshell. However, the most recent research shows this loss to be necessary for the chick to emerge from the egg. The chick needs oxygen and space to be able to move its head just enough to crack the shell while hatching. The evaporation of water creates the room and oxygen required.

Chicks have a special "egg tooth" that they use only to hatch the egg. This tooth is formed just before hatching and, amazingly, disappears after hatching. The eggshell is strong enough to protect the embryo during twenty days of incubation. However, it is also easily breakable so that the chick can emerge.

Furthermore, water loss ratio is adjusted to vary between 15 to 20% for ideal conditions depending on the type of eggshell. For instance, water loss in the eggs of loons is a few times higher than in others that incubate under dryer conditions.

The figure shows phases of development of a chicken egg in the ovary. It takes about fifteen to sixteen hours for a chicken egg to form after fertilisation.

The Design of an Egg for Durability

The durability of an eggshell is as crucial as its functioning in terms of air, water and heat. It has to withstand external impact as well as the weight of the incubating parent.

A closer examination reveals that eggs are designed for sufficient durability. God created smaller and larger eggs different from one another. Eggs of larger birds are usually harder and less flexible whereas eggs of smaller birds are softer and more elastic.

Chicken eggs are rigid and rough, but they do not break when falling over one another. The rigid shell also protects them from attack. If smaller eggs were to be as rigid and rough as the chicken egg, they would have broken much easier. Studies show smaller eggs are not rigid, but sturdy and flexible, which prevents them from breaking under impact.

The flexibility in the structure of an egg not only serves to protect the chick but also determines the way that the chick hatches it. A chick that will come out of a rigid and rough shell only needs to open a couple of holes at the blunt end of the egg before pushing its head and legs out. The chick meets the world by lifting the hat-shaped end cover that is formed by the cracks connecting these holes.25

The figure above shows the shell of the loon egg laid on wet and muddy ground. The shell is covered with a layer called the "inorganic spheres layer", which prevents the pores from closing and the chick from suffocating. The eggs of birds living under different conditions vary as well. The figure above shows the section of an eggshell of the egg of a rainbird. The specially crystallised outer layer protects the egg, where it is laid in a gravel bed, against impact and scratches.