10 Birds are the fastest and most powerful fliers in the animal kingdom. A bird’s wing is light, strong, and flexible. It is also convex in shape, curving slightly from front to back, which helps to pull the bird upwards as it flaps through the air. Although the size and shape of wings vary, they all share the same basic design. Alula This group of feathers from an owl covers the front edge of the wing. The alula provides lift to the wing during unsteady manoeuvres such as landing. Flapping failures Early inventors did not realize that flapping flight would always be beyond the power of human muscles. Within the limit A bird’s wings can bear its weight, plus anything it is carrying, such as food or nesting materials. Leonardo da Vinci Italian artist Leonardo da Vinci (1452–1519) was also a brilliant engineer. He was fascinated by how birds fly. He studied their wing structures and observed their flight. These observations inspired him to design many flying machines, but none of them took off. EYEWITNESS Icarus falling to the ground The Flying Philosopher etching Too high In Greek legend, Icarus flew too near to the Sun, causing the wax that held his feathers to melt. But birds flying at high altitude have to cope with quite different and much more real problems – scarce oxygen and intense cold. A bird’s plumage weighs more than its skeleton . Primary flight feathers The “primaries” produce the power for flight. The outermost primary feathers can be used for steering. Bald eagle carrying a mallard