* To express herself freely: Catherine is a young girl living in a patriarchal society where women have limited agency and voice. Her journal becomes a safe space for her to express her thoughts, feelings, and frustrations about her life, her family, and her future. It's a way for her to process her emotions and the pressures she faces.
* To preserve her memories: As a young girl, Catherine is experiencing a lot of firsts and changes. The journal serves as a way for her to document these events and preserve them, so she can reflect on them later.
* To communicate with her father: While Birdy's journal is primarily for her own personal use, she also uses it to communicate with her father, who is away for long periods of time. She writes to him about her daily life, her hopes and fears, and her desire for him to be home.
* To explore her identity: The journal allows Birdy to explore her own identity, her desires, and her sense of self. Through writing, she can experiment with different personas and find her own voice in the world.
Ultimately, Birdy's journal is a crucial tool for her self-discovery and survival in a restrictive and often oppressive society. It gives her a sense of control and agency in her life, even if it is a small one.