What are the trifles in Glaspell’s Trifles?

In Glaspell's play, the "trifles" are the quilt with erratic stitching, the bird cage, and the dead canary in a pretty little box.

Ironically, the "trifles" found in the kitchen are key items to providing the motive for which the men spend their time searching upstairs. They ignore the kitchen since the County attorney has asked the sheriff as they stand in its doorway,

"You're convinced that there was nothing important here--nothing that would point to any motive?"

and the sheriff has replied, "Nothing here but kitchen things."

So, the men go upstairs and leave Mrs. Hale and Mrs. Peters to attend to the broken jars of preserves since "women are used to worrying over trifles." However, the broken jars of preserves are not the only "trifles" that they discover. For, as they straighten the kitchen. Mrs. Peter finds a quilt that Mrs. Wright has worked on; then, Mrs. Hale notices that the sewing is erratic at one point whereas it is neat everywhere else that has been stitched. "Why, it looks as if she didn't know what she was about!" Mrs. Hale exclaims. Then, because bad sewing always makes her "fidgety," she fixes it.

While Mrs. Hales sews, Mrs. Peters gathers the clothing that Mrs. Wright, who is in jail, has requested. Needing a string or something to wrap these items, Mrs. Peters looks in a cupboard and finds a bird cage. This cage has a broken door because a hinge has been pulled apart.

Later, Mrs. Hale suggests that Mrs. Peters take the quilt to Mrs. Wright to finish. Agreeing, Mrs. Peters looks for Mrs. Wright's quilt patches in the sewing basket, but finds none. Then, she sees a pretty red box and, thinking the scissors may be in it, she discovers instead a dead canary wrapped in silk. Its neck has been wrung. Just as they look upon the poor bird in horror, the men descend the stairs.

Facetiously, the county attorney alludes to the wives' remarks about whether Mrs. Wright was going to "quilt or knot" the quilt she was sewing,

"Well, ladies, have you decided whether she was going to quilt it or knot it?"

Mrs. Peters replies with dramatic irony, "We think she was going to--knot it." Dismissively, the attorney responds,

"Well, that's interesting, I'm sure. (Seeing the bird-cage)  Has the bird flown?"

Mrs. Hale tells him that they think the cat got it. She adds that Mrs. Wright liked the bird and was going to bury it in the pretty box.

When the men start back up the stairs, Mrs. Hale and Mrs. Peters confer with one another about the cruelty of Mr. Wright and her terrible isolation and loneliness without children or friends. Their sympathy for this poor woman waxes as they talk; finally, they make their decision to hide the "trifles" of the bird and the box from the sheriff and county attorney.