The poem is very short and deliberately hard to pin down, but its opening image is clear enough: a city has recently been blown up, and the people left in it are afraid of a raven. Not just any raven, but a "never-done" one, a scavenger that never finishes feeding. The title, "Carrion-eater," backs this up. In the aftermath of destruction, death becomes a steady supply of food for something patient and unbothered.
The second stanza turns stranger. A "superficial fisher" with no loss and no compass seems to be someone who skims the surface, untouched by what has happened and with no sense of direction. The final line, "the thing just may get by," is ambiguous. The "thing" could be the raven, or any survivor who manages to carry on. The judging tone suggests unease, even bitterness, about who gets through disaster and how. The mood is cold, uncertain and watchful, with fear sitting alongside a kind of grim irony.