What kind of wings did Leonardo da Vinci’s ornithopter design imitate?

Leonardo da Vinci’s ornithopter design imitated bird wings.

An ornithopter is a flying machine intended to generate lift by flapping wings, and Leonardo studied this idea extensively. His designs used observations of birds and bats to investigate wing shape, movement, balance, and the forces involved in flight.

Leonardo’s human-powered ornithopters were never capable of sustained flight. Human muscles cannot provide the power-to-weight ratio needed to flap sufficiently large wings, especially when the machine must also carry its frame and pilot. Leonardo eventually recognized that gliding and mechanical flight required a deeper understanding of air resistance and lift.

The ornithopter concept is distinct from Leonardo’s aerial screw. The ornithopter copies the flapping action of animals, while the aerial screw proposes rotary movement. Modern ornithopters can fly when powered by engines or lightweight mechanisms, but they are not evidence that Leonardo’s original machines worked.