How is the bird a metaphor in Trifles?

oth the bird and the cage serve as a metaphor in Trifles. The bird represents Minnie as a young woman before marriage. Mrs. Hale describes Minnie as "kind of like a bird herself- sweet and pretty, but kind of timid- fluttery." After her marriage the cage takes on a meaning of its own, as like the bird, Minnie is caged. Her husband's abuse and the fact that Minnie is caged within her home find them similarly imprisoned. In the end, John strangles the bird in the cage in the same way he strangles the life out of his wife.