There was controversy in the UK after a recent ban on shooting crows, who attack lambs, going for the eyes and tongue. Apparently they do the same with piglets. And of course crows pecked out the eyes of the dead during the plague. They are said to exist all over the world, apart from Antarctica.
Because Lyuda died with her mouth open, and her body was discovered leaning against a large rock, this may have provided a landing spot for a crow or other carrion before the bodies were covered with snow, and afterwards the air pocket at water level would allow decomposition, with the varying flow of water directly into her mouth flushing away the remains of the tongue and other tissues.