In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.

Sentence1: Nell found a baby bird that had fallen from its nest. Sentence2: She brought the bird to her brother, who knew about animals. Sentence3: The brother asked Nell to dig for worms to feed the baby bird. Sentence4: Nell dug and brought a worm to feed the bird. Sentence5: The brother stopped Nell before she gave the bird a cutworm.
Brother, Nell, Baby bird