The Storm Crow (Storm Crow, 1, Band 1)

In the tropical kingdom of Rhodaire, magical, elemental crows are part of every aspect of life... until the Illucian empire invades, destroying all the crows. That terrible night has thrown Princess Anthia into a deep depression. Her sister, Caliza, is busy running the kingdom after their mothers death, but all Thia can do is think of all she has lost. But when Caliza is forced to agree to a marriage between Thia and the crown prince of Illucia, Thia is finally spurred into action. And after stumbling upon a hidden crow egg in the rubble of a rookery, she and her sister devise a dangerous plan to hatch the egg in secret and get back what was taken