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?
The Creator of these birds, Allah, 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. Likewise Qur'an draws attention to "birds lined up in flight" and informs us about a consciousness that is inspired in these creatures by Allah:
Do you not see that everyone in the heavens and earth glorifies Allah, as do the birds with their outspread wings? Each one knows its prayer and glorification. Allah knows what they do. (Surat an-Nur: 41)
Have they not looked at the birds above them, with wings outspread and folded back? Nothing holds them up but the All-Merciful. He sees all things. (Surat al-Mulk: 19)
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 500F (100C). The sparrow's 1080F (420C) body temperature and a fieldfare's 109.40F (43.50C)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 land animals 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.
Birds prefer to travel in flocks on long trips. The "V" formation of the flock enables each individual bird to save about 23% energy.
Birds also use their energy very efficiently. They demonstrate significantly higher efficiency in energy consumption than do land animals. For instance, a migrating swallow burns four kilocalories per mile (2.5 per kilometre) whereas a small land animal would burn 41 kilocalories.
Mutation cannot explain the differences between birds and land animals. 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. 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, Allah has created them individually.
The sparrow's heart beats 460 times per minute. Its body temperature is 1080F (420C). 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.
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
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.
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 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.
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).
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 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.
Slope soaring depends on the movement of air rising to the hilltop.
Vortex ring type thermal soaring takes place under the base of a big cumulus cloud.
Columnar type thermal soaring is only possible in warm regions.
Gust soaring is possible where two fronts meet.
DESIGN IN BIRDS
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.
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.
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.