Aaboo is a young friendly Harpy whom was met by Aang and Starfire during their traveling through the great desert. She usually likes to hang around up in the crows nest and gotten to know Aang the most since he spent most of the time up there too. She was originally born in the Harpy Mountains but she left because of the lack of respect by the other harpies that lived there.
One night, she went and was talking to Aang, trying to cheer him up. As the conversation went on she found out from him all that has happened to him, mainly with him and Katara.
During the incident with Ventus, she was acting frantic and told everyone Jhen Mohran was coming after throwing back the money Ventus stolen from them. With her early warning, she got everyone ready and gotten everyone safely out of its way.