Zoo Day is a short story in the Dresden Files series by Jim Butcher. It is set at the same time of Day One, and is in turn narrated by Harry Dresden, Margaret Angelica Dresden and Mouse. It is included in the anthology Brief Cases.
Harry Dresden, his daughter and Mouse are spending a day at the zoo. Dresden meets and rescues Austin, a young warlock just arrived into his powers. Margaret confronts a pack of haunts after her and the fears that attracted them. Mouse meets his brother and chases him away.