What is the name of Leonardo's codex dedicated to the flight of birds?

Leonardo’s codex dedicated to the flight of birds is the Codex on the Flight of Birds.

Leonardo compiled the manuscript around 1505 in the context of his continuing studies of air, motion, anatomy, and mechanical flight. Rather than simply copying observations, he analyzed how birds use their wings, tails, and changing body positions to remain aloft and maneuver through the air.

The codex contains 18 folios and is now held by the Royal Library in Turin. Leonardo proposed designs for flying machines based partly on his observations of birds, though his machines could not reproduce the power and efficiency of living wings. The manuscript is therefore both a natural-history study and an engineering notebook.

One especially notable insight is Leonardo’s observation that a flying bird’s center of gravity does not coincide with its center of pressure. That idea reflects his effort to explain flight through physical principles. It should not be confused with the Codex Atlanticus, Codex Arundel, or Codex Leicester, which are separate collections of Leonardo’s writings and drawings.