The poem drops us into a hot, crowded city through a rush of fragments: dust, flies, exhaust, cut melons, shaded courtyards, and blood on the paving stones. Beauty and violence sit side by side, and the speaker doesn't comment on either. The title, "In Babylon," suggests an ancient, overwhelming city, though the poem never says which real place it has in mind.
At the center is a butterfly missing half a wing that still flies "so well." The speaker's question sounds like quiet amazement. In the second stanza, a sound too deep to hear shakes the towers and sets off car alarms, as if the city itself were uneasy. The butterfly, though, doesn't "miss a drunken beat," carrying on with its wobbling flight.
The mood is watchful and uneasy, but also strangely admiring. The speaker seems to find a small kind of hope in this damaged creature that keeps going while everything around it trembles.