Shrike

It was called Strole, and it was home to fifty tough, dust-hardened scavengers who robbed Old-Tech sites when they could find them and scrounged salvage from the leavings of larger towns when they could not. Shrike lived with them, but he was no scavenger. When criminals from one of the great Traction Cities escaped into the Out-Country, Shrike would track them and cut off their heads, which
he carefully preserved. When he crossed that city’s path again he would take the head to the authorities, and collect his reward.

Chaper 13, The Resurrected man, Mortal Engines, pg 53/152