Miss Jackdaw is a European ymbryne.
Hollow City[]
Miss Jackdaw would go to The Peculiar Archives for some reason. When the wights took The Peculiar Archives, Miss Jacksaw was captured and taken away from the loop to Devil's Acre. The wights would leave some of her feathers behind.
Library of Souls[]
While not specifically stated, it is believed that Miss Jackdaw was forced to help reopen the loop that held Abaton and helped collapse the loop.