Three brief scenes, each one a small image of things dying or being kept from where they belong. In the first, a police officer sprays poison on an urban garden. The speaker's question, "why should I dream of this?", suggests the image has followed them into sleep and won't be shaken off. In the second, the speaker carries a dead houseplant outside but can't find bare ground to bury it, because snow covers everything. Even the simple act of laying something to rest is blocked. In the last scene, a house finch with an eye disease can't migrate, yet keeps singing.
The title, "Threnody," means a song of mourning, and the poem works that way without ever saying "I grieve." The speaker mostly observes, and the feeling comes through the quiet details. The mood is bleak but tender. The finch's endless warbling adds a small, stubborn note of life: it's hard to tell whether it is comforting or heartbreaking, and it is probably both.