Because of an old superstition, several ravens are kept at the Tower of London at all times. These ravens are enlisted soldiers of the Kingdom, and have occasionally been dismissed for bad conduct. While wild ravens live for 10-15 years, Tower ravens can live past 40 years.

“Their presence is traditionally believed to protect the Crown and the tower; a superstition holds that “if the Tower of London ravens are lost or fly away, the Crown will fall and Britain with it””