Hedwig
Background
Hedwig is the owl familiar of Harry Potter.
During the events of Harry Potter and the Sorcerer's Stone (2001)
Hagrid knocks on the Ollivanders store window and shows Harry his birthday present, Hedwig. Hedwig spends the school year with Harry.
During the events of Harry Potter and the Chamber of Secrets (2002)
Hedwig starts to screech and Harry tells her he can't let her out of her cage. Later Harry sits outside with Hedwig and relates to her his troubles.
During the events of Harry Potter and the Prisoner of Azkaban (2004)
Tom The Innkeeper takes Harry to Room 11 where Hedwig is already inside.
During the events of Harry Potter and the Goblet of Fire (2005)
Harry writes a letter to Sirius Black and gives it to Hedwig to deliver.
During the events of Harry Potter and the Order of the Phoenix (2007)
After he is expelled from Hogwarts for using magic out of school, Harry apologizes to Hedwig for getting angry and looks at his photo of James Potter and Lily Potter and then remembers the murder of Cedric Diggory at the hands of Voldemort.
During the events of Harry Potter and the Half-Blood Prince (2009)
Ginny Weasley sees Hedwig in the living room and asks Mrs Weasley when Harry arrived.