Next instant I heard a loud clap, and a surge of joy went through me, for I thought that the bullet had found its billet.

But alas! it was not so.
The clap was that of the air disturbed by the passing of the ball and the striking of this air against the stiff feathers of the wings.

Anyone who has shot at great birds on the wing with a bullet will be acquainted with the sound.

Instead of falling the vulture recovered itself.

Not knowing the meaning of this unaccustomed noise, it dropped quietly to earth and sat down near the bodies, pitching forward in the natural way and running a few paces, as the others had done that afternoon.
Evidently it was quite unhurt.
"Missed!" gasped Hans as he grasped the rifle to load it.