"Ghost Bird" is the alias assumed by the doppelganger of the 12th expedition's biologist.
Like the other returnees of the 12th expedition (excluding the psychologist), the returned biologist appeared outside of Area X through unknown means. She was found standing in an empty lot, staring at a crumbling brick wall. Following her recovery, she was detained by the Southern Reach for debriefing and observation. During this time, she asked to be referred to as "Ghost Bird," a name her husband once used for her.