Codex on the Flight of Birds is a relatively short codex from c. 1505 by Leonardo da Vinci.[1]
It comprises 18 folios and measures 21 × 15 centimetres. Now held at the Royal Library of Turin, the codex begins with an examination of the flight behavior of birds and proposes mechanisms for flight by machines. Leonardo constructed a number of these machines, and attempted to launch them from a hill near Florence. However, his efforts failed.[2]
In the codex, Leonardo notes for the first time that the center of gravity of a flying bird does not coincide with its center of pressure.
The date of the Codex on the Flight of Birds is ascertained by the note on the last folio facing the architectural design on the cover: 1505, 14th and 15th April.