Codex on the Flight of Birds of a kite as seeking a wind current. When the winds are high, one will see the bird very high in the sky, but when the winds are low, the bird stays closer to the ground. Leonardo describes how a bird rests in the air, after flapping its wings to gain altitude, by gliding downward to the ground. Folio 6 contains multiple diagrams of birds flying and their bone structure, and all of the commentary is on flight and how birds fly the way that they do. Leonardo starts off by describing how a bird ascends or descends in different
Beak from the Latin "ungus", meaning "nail" and "rostrum", meaning "beak". Rictal bristles are stiff hair-like feathers that arise around the base of the beak. They are common among insectivorous birds, but are also found in some non-insectivorous species. Their function is uncertain, although several possibilities have been proposed. They may function as a "net", helping in the capture of flying prey, although to date, there has been no empirical evidence to support this idea. There is some experimental evidence to suggest that they may prevent particles from striking the eyes if, for example, a prey item is missed or broken