As he sees it, the bird, tail and all, reflects nothing more than Leonardo's interest in flight.
Its legs were built for walking, not running, and he probably moved like a bird — tail and head parallel to the ground.
This adds more of a reptilian look, as opposed to a straight bird tail.
In recent years it has become established that bird tails have important effects upon their flight.
For example, bird tails are known to produce lift during flight [1], [2].
Suggesting that tail membrane may act as a splitter plate, streamlining the body of the bat, as has been suggested previously for bird tails [3].
Furthermore, sufficient flight stability is essential for all flying animals and bird tails are thought to be a key component for overall flight stability [5], [6], [7].
Although previous authors have hypothesised that bat tail membranes perform similar aerodynamic functions to bird tails [9], [10], [11], [12], empirical tests of bat tail aerodynamics have yet to be undertaken.
This is a slightly surprising result since bird tails clearly do have an important lifting function, particularly at lower speeds [1], [2], and a similar role had been hypothesised for the bat tail membrane [9], [10].
Bird tails also appear to reduce body drag, by acting as a splitter plate [3] that reduces flow separation behind the body, essentially making the body more streamlined [4].
Bird tails are also thought to be important for flight control, particularly during take-off and landing when the tail is fanned out and the angle of attack increased, augmenting lift production, improving manoeuvrability and possibly reducing wing stall [8], [9].
