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.
Q: Sentence1: She opened the back door and propped it. Sentence2: The dog didn't notice. Sentence3: A loud noise got her attention. Sentence4: It was a bird in the backyard. Sentence5: She ran outside to check it out.
A:
Dog, Bird