The canary symbolizes Minnie. Her marriage becomes her cage, and in killing the canary, her husband kills a part of her as well as the only thing left in her life that gave her beauty and pleasure. Only Mrs. Peters and Mrs. Hale appreciate the significance of the canary and the grueling, lonely life Minnie led with her husband, and this reasoning leads them to understand also that Minne kills her husband with her sewing scissors in retribution for his cruelty.. When they say at the end of the play “knot it,” they seem to answer the question the men ask (condescendingly) about Minnie’s quilting, but in reality pronounce Minnie “not guilty” for her crime because they empathize with her so completely.
Minnie doesn't kill the bird; her husband does. Minnie had bought the canary to keep her company because she was so lonely on the farm. When she married her husband, John, she was a pretty young girl who liked to socialize. John moved her to a farmhouse in the middle of nowhere and changed her life forever. John had a bad temper and probably killed the bird because he got mad at Minnie for some trivial thing and punished her by killing the only thing she had in her life. This was probably the "last straw" for Minnie and what led her to kill her husband. During their years of marriage, Minnie wasn't allowed to socialize with anyone, they never had any visitors, and she never left the house. They never had children. The canary was the only thing she had to help her feel better about being isolated from the world.
Minnie does not kill her husband with sewing scissors in retribution for his cruelty. He died of a rope around his neck.
The inference of all the evidence is that Minnie strangled him while he was asleep.
Minnie's husband, Mr. Wright strangled the bird. The reasons are not plainly given, but it is inferred that he did not like the bird so he got rid of it. The bird in its cage symbolizes Minnie's life and when the bird died, she could not handle it any longer and strangles him while he sleeps.