It has long been appreciated that what was achieved during the invention of airplanes, had long been achieved in nature by birds. The basic concept is to create a balance between weight and strength. Flight is a special adaptation of birds that enables them to obtain food, travel, escape from predators and reproduce. The flight mechanics of bird flight uses the concept of establishing higher pressure just below the wings, as compared to above the wings. This produces the lift effect that enables the bird to lift off the ground.
The bird achieves this by flapping the wings downward and forward, increasing the speed of air below the wings hence the reduced pressure. According to Wikipedia on, ‘bird flight’, gliding birds manage to obtain a “vertical force and a forward force from their wings.” However, Wikipedia continues to point out that during flapping birds still manage to gain height due to the lift force, and move forward due to the rotation of the lifts. The tail just like in fish and the cheetah acts as a rudder.
In flying, birds have managed to acquire various adaptations geared towards reducing the net body weight and the strength of bones. The bones are specifically hollowed for weight reduction. Furthermore, bones in some areas have been fused to reduce the total number of bones. Examples include the fusion of the vertebrae bones and bones of the pelvic girdle, and the fusion of some finger and leg bones. Some of the bones of the fingers and the legs found in other vertebrates are also absent in birds.
Finally, birds are also known to reduce weight by keeping their reproductive organs tiny when they are not in use for breeding. As mentioned earlier, the tail acts as the rudder helping to maintain balance during flight. The bird’s respiratory system is also adapted to further improve flight efficiency. In terms of proportions, birds have dedicated a much larger volume of their body towards the respiratory system than human beings.
Detailed Discussion of How the Bird Flies, this is because their respiratory system consists of the nose, mouth and the lungs: the inhaled diffuses in blood at air sacs in the lungs. Furthermore the air sacs do not always collapse completely. On the other hand, inhaled air in birds travels in one direction hence there is no wastage of air and the air that diffuses into the blood is always rich in oxygen. The Inhaled air in birds, moves to the posterior sacs and then to the lungs during exhalation.
During the second inhalation, the air in the posterior sacs moves to the anterior sacs. During the second exhalation air from the anterior sacs is removed to the outside of the bird. This system ensures that birds always have a rich supply of oxygen since there is no mixing of deoxygenated and oxygenated air. The respiratory system of the bird is also so efficient as to reduce the ratio between breaths and heartbeats.
According to Klappenbach on ’10 Facts about Pelicans,’ diving birds such as the pelicans have unique adaptations as compared to other birds. The wings of the pelicans and cormorants do not retain film of air, but quickly soak to allow for deep diving. The pelicans also have slit nostrils to prevent the entry of water as they dive. Furthermore, this group of birds aligns its wing backwards to increase their speed when diving to catch prey.