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
Celeus (bird) 19–32 cm. They are generally not sexually dimorphic and have evolved specialised morphology to match their unique lifestyle. The "Celeus" beak differs from other woodpeckers in that it is mainly curved, not long and without nostril feathers. Like other woodpeckers its beak has a chisel like cutting edge. A hard rhamphotheca and complex beak microstructures strengthen the bill for pounding and drilling. The tail has evolved for support, clinging and climbing, acting as a third leg or tripod. The pygostyle (tail vertebrae) is larger for strong tail muscles to be inserted and it is more or less stiff. There are