When not in use, it's retracted by a woodpecker, & it may wrap around under the skull, beneath the skin
. . around the back of the skull beneath the skin, and over the top... [DOC] [TLE] Why a Woodpecker Doesn't Bash Its Brains In - The Infinite Spider [PAR] Sep 29, 2015 ... Why Does a Woodpecker Not Bash Its Brains In When It Pecks?