Wind, Tail and Balance in Bird Flight
Righting a capsize, rising like a kite over Fiesole, and the five steering positions of the tail
Leonardo analyzes how birds use wind, balance, and tail to steer. A bird descending eastward over a southern wind on its right wing will capsize unless it turns its beak north, so the wind strikes its wing-palms beyond the center of gravity and lifts the front. A broad-winged, short-tailed bird rises by wheeling to wedge the wind beneath its wings, as he saw a kite do on the way to Fiesole above the Barbiga in '05, on 14 March. A further passage sets out five positions of the tail and how each low or raised, tilted end turns or circles the bird. A large upside-down study of a leg in pen and red chalk fills the center of the sheet, with small bird and wing sketches in the margin.
On this page
Rising by wedging the wind under broad, short-tailed wings
A bird with wide wings and a small tail rises by raising its wings strongly and wheeling to catch the wind beneath them, the wind forming a wedge that thrusts it up quickly. Leonardo cites a kite he saw on the way to Fiesole, above the Barbiga, in '05 on 14 March.
Righting a capsizing bird: beak to the north
A bird descending east over a south wind on its right wing will be overturned unless it quickly turns its beak north. Then the wind strikes the palms of its wings beyond its center of gravity and raises the forward part again.
The five positions of the tail as a rudder
The tail has five motions: flat for level flight, both ends low for climbing, both ends high for descent. When it is low with one side lower, or high with one side higher, the bird turns or circles toward one side or the other accordingly.
Large red-chalk study of a leg
A large leg is drawn upside-down in pen and red chalk across the center of the sheet, unrelated to the flight text around it. It is one of the figure studies interspersed through the codex.