When we examine birds, we see that all the features of their bodies have been designed especially for flying. For example, the body structure of eagles, which are known as one of the birds with the best capabilities for movement, is perfect in every way. The eagle needs to be both light enough to be able to take off from anywhere easily and strong enough to carry its prey after catching it. A bald eagle has more than 7,000 feathers. However, when you put all these feathers together, they weigh only approximately 500 gr. (18 ounces). In addition, in order to provide a lighter body weight, the insides of the bones are hollow. In many parts of these bones there is nothing but air. The total weight of a bald eagle tips just over 272 gr. (9.5 ounces). In short, the body weight of the eagle is ideal for flying.
An eagle derives the force it needs for flying from the downward flapping movements of its wings. For this reason, the number of its muscles that push the wings downwards is greater than the number of the muscles that push them upwards. Flight muscles are very important for an eagle.
These muscles generally weigh half of the bird's total body weight. The eagle can fly faster or slower by changing the position of its wings. When the eagle wants to fly faster, it turns the front sides of the wings inwards towards the wind and thus slices through the air. When it wants to go slower, it turns the wide sides of its wings against the wind.
All the eagles have an extra eyelid called a "nictitating membrane." The function of this special lid is to clean and protect the eyes of the birds. For example, eagles usually pull the membranes over their eyes when feeding their chicks. It is a precaution to protect the eyes of the parents from any harm that these chicks might accidentally inflict as they lunge for food.
The design of the eagle concerns not only a flawless flight technique, but also a special design in its feathers for landing. As the eagle starts to go down, it decreases its speed by pulling its tail down at an angle to its body. It lowers the edges of its wings so as to use them as brakes. But, as the eagle loses speed, turbulence formed on the upper surface of the wings increases its danger of stalling. The eagle counters this danger by raising the tufts of three or four feathers that are found on the edge of its wings. These let in a stream of air across the wing surface, which maintains a smooth flow, and enable the bird to easily complete its flight.
There is an evident fact in the examples given so far. Even a mere couple of details in the design of an eagle's body are so perfect that they couldn't have come into existence by chance. This clearly proves to us that eagles also, like all other birds and creatures, have been created by Allah, the All-Powerful.