A Throne of Swans by Katherine and Elizabeth Corr From Goodreads: In a world where the flightless are ruled by those who can fly… When her father dies just before her birthday, seventeen-year-old Aderyn inherits the role of Protector of Atratys, a dominion in a kingdom where nobles are able to transform at will into the bird that represents their family bloodline. Aderyn’s ancestral bird is a swan. But she has not transformed for years, not since witnessing the death of her mother – ripped apart by hawks that have supposedly been extinct since the long-ago War of the Raptors.  With the benevolent shelter of her mother and her father now…