One of the most fascinating sights in nature is to behold the amazing diversity of living creatures that can glide or fly. Throughout history, mankind has been fascinated by birds in flight. Is there a more regal sight than the eagle soaring high above us in the sky? Since ancient times, men’s imagination and dreams have turned to the sky, and we have longed to fly as freely as the birds.
It is remarkable that there are over 10,000 species of birds, but it is not only birds in nature that can fly. We also see hundreds of flying insects, bats which are flying mammals, and there are reptiles and fish that can glide. Mollusks are no exception. There is even the Humboldt squid which leaps out of the water, like a flying fish, and propels itself with jets of water while in the air. This would be a frightening sight, but the flying squid is most likely evading a predator.
To fully understand flight, we must study aerodynamics, aeroelasticity, stress1 and buckling2 stability in lightweight structures, propulsion and energy transfer, and control system theory. If we apply modern engineering to the study of flight, we come to be in awe of the flying skills of birds, insects, and mammals seen in nature.
- 1) Stress is the internal forces that resist change of the shape when an external force such as compression or twisting is applied.
- 2) Buckling is a mathematical instability, leading to a failure mode. It is characterized by a sudden sideways failure of a structural member subjected to high compressive stress.
In fact, much of today’s advanced technology has resulted from mankind’s great desire to fly. The earliest attempts to build flying machines were crude attempts to copy what men observed in nature. Early in the 20th century, the basic skills in engines, materials, and wing theory had developed enough to allow the first self-powered aircraft. Although it might seem that today, after more than a century of intensive development around the world, our aircraft are more advanced than nature, we find out that this is not the case.
One of the most amazing scenes in nature is to watch the hummingbird hover and dart expertly from flower to flower to sip tiny drops of nectar. Today, using high speed photography, we can see the motion of the hummingbird’s wings which are flapping 50, 60, or even 80 times per second—so fast that a humming sound is created. The hummingbird in flight has the highest metabolism of any animal. Its heart rate can reach 1,260 beats per minute and its respiration can be as high as 250 breaths per minute. To sustain their metabolism, the hummingbird must consume its weight in nectar each day, and stores up just enough to survive until the next day. In other words, every hummingbird lives just a few hours away from starvation.
Every aspect of the life of a hummingbird is a marvel. Recently a professor at Stanford University compared the performance of the hummingbird wing to the blades from an autonomous microhelicopter. He used the most sophisticated microcopter available, itself about the size of a hummingbird. The researcher rotated the wings of 12 species of hummingbird on an apparatus designed to test the aerodynamics of helicopter blades. Cameras recorded airflow around the wings, and sensitive load cells measured the lift3 and drag4 of the wings at different speeds and angles. Even spinning like a helicopter, rather than flapping, the hummingbird wings excelled. One species—Anna’s hummingbird—was 27 percent more efficient than the highly engineered microcopter blades.
- 3) Lift is the force that acts as a right angle to the direction of motion through the air. The lift force exerted on the wing enables the airplane fly.
- 4) Drag is the force that acts opposite to the direction of motion.
Watching a high speed video of the hovering hummingbird, we can see the perfection of its flight control skill. Although the wings are beating at incredible speed, the hummingbird’s head remains exactly still, allowing it to sip the flower nectar as quickly as possible. Hummingbirds can even fly backwards. A team of aerospace engineers, working for years, cannot design a flight control system to equal the amazing little hummingbird.
Many birds must migrate each year to survive the change in the seasons. Bird migration reveals the optimization of design and of system integration seen only in nature.
Everyone who has watched a flock of Canadian geese migrating has noticed the characteristic “V” formation of the flock. This pattern allows the flock to expend 70% less energy during a long migration. While each goose, individually, is an expert flyer, their skills must be greater to take advantage of the V formation. When the lead bird flaps its wings, a downward-moving vortex of air trails from the tips of its wings. However, in the adjacent region there is upward moving air behind the lead bird. By positioning themselves optimally behind the lead bird, and adjusting their flapping to the best phase relative to the lead bird, the trailing birds use much less energy. The lead bird will of course tire more quickly, so the leadership position is changed to share the burden equally across the flock.
Bird watchers have long known that a tiny, boreal forest songbird known as the blackpoll warbler leaves New England in the U.S. and eastern Canada each autumn, and migrates to Venezuela and Columbia in South America. However, the migration path was unknown. The blackpolls were seen to appear in Puerto Rico, Cuba, and the Greater Antilles during their migration. However, it seemed impossible that they could fly directly over the Atlantic Ocean, as the distance was so great. The blackpolls would not be able to eat or drink during the flight, nor could they land. To come down in the ocean was to die.
A research team headed by Bill DeLuca of the University of Massachusetts was finally able to answer this mystery. DeLuca and his team were able to attach tiny geolocator “backpacks,” weighing only 0.5 g, to blackpoll warblers. After a complete season, several of the birds were recovered and the geolocators were analyzed. The data gave proof that the tiny blackpolls complete a nonstop flight over the Atlantic, traveling a distance of 2,300 to 2,800 km [1,430 to 1,740 miles] in just two to three days! According to DeLuca, this is one of the longest nonstop overwater flights ever recorded for a songbird, and finally confirms what has long been believed to be one of the most extraordinary migratory feats on the planet, a feat that is “on the brink of impossibility.”
The long distance migration of birds such as the blackpoll requires a precise balance between the bird’s metabolism and aerodynamics. Each bird species has an optimum speed at which it can fly. Flying slowly uses a huge amount of energy, as does flying at maximum speed. To survive the extraordinary migration of over 2,300 km [1,430 miles], each blackpoll must fly at the optimum speed for energy conservation. If a blackpoll flies to use just 1% too much energy, it may fall into the ocean 23 km [14 miles] short of its island rest stop and perish. In addition, all migrating birds have an ability to navigate. Somehow birds in their first migration can find their winter home, despite having never been there before. This is yet to be fully understood by science.
The remarkable combination of metabolism, shape, coordination, and senses makes every bird, every flying insect, and every bat a testimony to God’s power of creation. Every aspect of each of these thousands of flying creatures must be just right. The consequences of being just a little less than optimum—in every characteristic—are death. Only God can endow so many diverse forms of life with the ability to fly. Whether we are in delight, watching the amazing ballet of the hummingbird, or exasperated, waving our hands in futility at the nimble fly or the bobbing mosquito, we must stand in awe at God’s creation.
Through the miracle of thousands of birds, insects, and mammals that can fly, we can realize that every creature on earth, whether majestic or common, is designed perfectly for its intended place in nature. Only God has the ability to design everything perfectly. Therefore, we must believe that God exists, and follow God’s plan for us.
The migrating bird is perfect for its place in nature, but it must not veer from the path that God has intended for it. It must follow the plan of perfection in order to reach its destination. In the same way, if we do not veer from God’s plan for us, we will reach the destination of our journey, the kingdom of heaven.