The bird in the Susan Glaspell's play, Trifles, symbolizes happiness, and the ability of one person to rob another of that happiness.
Mrs. Minnie Wright has been accused of killing her husband, and as the play begins, several men enter to search for evidence that will convict her. Two women, Mrs. Hale and Mrs. Peters, also enter, seemingly aligned with the opinions of the men, there to gather some belongings for Mrs. Wright who is in jail.
As the men search for clues, the women gather some things for Mrs. Wright. In their search, they come across a damaged birdcage in a cupboard, its door half wrenched off the cage. They are curious about the cage and its missing occupant. As they continue to look around, they have to listen to the derogatory comments the men make about what a poor housekeeper Mrs. Wright was, and how she worried about "trifles," which the women know are anything but unimportant, meaningless concerns or tasks.
The women begin to feel some sympathy for the sad life Minnie lived with her "hard" husband. They discover her sewing box, and in it, the body of the dead bird: wrapped in silk and placed in a box…to be buried, they assume. Its neck has been wrung: a brutish horrifying act; the realization the women come to is that Mr. Wright killed the bird, killing Mrs. Wright's only joy in life. Mrs. Hale comments on the reality of Mrs. Wright's existence.
MRS HALE (examining the skirt). ...She used to wear pretty clothes and be lively, when she was MInnie Foster, one of the town girls singing in the choir. But that--oh, that was thirty years ago...
MRS. HALE. Not having children makes less work--but it makes a quiet house, and Wright out to work all day, and no company when he did come in…
MRS. HALE. She--come to think of it, she was kind of like a bird herself--real sweet and pretty, but kind of timid and--fluttery. How--she--did--change...
MRS. HALE (with a slow look around her.) I wonder how it would seem never to have had any children around. (Pause.) No, Wright wouldn't like the bird--a thing that sang. She used to sing. He killed that, too.
All of these statements show a progression of change in Mrs. Wright, and John Wright's subjugation of her. Not only did the woman change from the lively and lovely woman of thirty years before, but she had no children. It's logical to assume that she was very lonely. However, she found some joy, some relief from the "stillness," in the form of a little bird. It was a bright spot in her dark existence, and John Wright killed it, as (Mrs. Hale observes) he killed every other good thing in her life. In killing the bird, Wright killed Minnie's happiness. Is it irony or poetic justice on Mrs. Wright's part that her husband died being strangled in his sleep, while the bird died with his hands around its neck?
In many respects, the bird can represent so much in terms of individual voice and identity. The bird lives in a cage, silenced and contained from the rest of the world. To a certain extent, the bird has learned to live in its contained condition. Yet, when Mr. Wright kills the bird, it is enough to send his wife over a threshold where violence and murder are the only solutions. For Mrs. Wright, the killing of the bird represents the ultimate in the attempt for male dominance over women. The bird's death reflects that the encroaching male patriarchy won't be content until it controls every single aspect of all existence. If the bird can be seen as women's voices and role in the time period, then the containment or silence of the caged bird is one aspect of being in the world. Yet, with its death, there is almost a statement that men won't be happy unless women are completely subjugated to them. This is seen as something that Mrs. Wright cannot take. The idea that "it was only a bird" is not simply valid because Mrs. Wright viewed it as so much more, as representative of her condition and women like her. The bird's death was not going to be symbolic of her own condition, though, and this becomes why she feels the need to take action.