The Plague (Feather and Bone: The Crow Chronicles)

Crows lie dead all around the Gathering Tree and the terrified survivors scatter. Sick and alone, Kyp knows only that he must find Kym, who has been captured by humans and taken far to the east. A crow without a flock flies on only one wing, and Kyp has no one to keep watch or provide warning when danger threatens. But gradually other crows join him in his relentless journey -- deep into the heart of a vast and frightful human colony.