How a bird beats its wings to land
Frequent wing-beats break the impetus of descent and soften the force of the impact
A small sketch of a bird with open wings sits at the head of the leaf, above a passage in mirror-writing. Leonardo observes that a bird beats its wings rapidly as it comes in to alight, descending from high to low. The purpose, he notes, is to break the impetus of the fall, to lighten the body, and to lessen the force of its landing.
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Rapid wing-beats while alighting
As it settles from high to low, the bird uses a dense beating of the wings. This checks the impetus of the descent, lightens the body, and diminishes the force with which it strikes the ground. The note treats the landing as a problem of controlling momentum.