Five short lines, and the poet has already staged a small comedy of scale. "I sing the house fly" borrows the grand opening gesture of epic poetry, the bard calling up his subject before a long tale of heroes and wars. Here the hero is the most ordinary insect in any building. The poem's central idea lies in that gap: a creature we swat and ignore is given a ceremonial welcome, and in the process the quiet, cold, serious place around it begins to look a little absurd, or at least a little lifeless.
The setting is built from one sharp adjective. The books are "cold," which suggests an unheated reading room, but also knowledge that is stored rather than lived, shelved and untouched. Against that stillness the fly is the only warm, moving thing. The line "first to sit among the cold / books books books" also leaves a pleasing ambiguity. First fly, perhaps, but also first visitor, first reader. The poem never says the fly reads, yet it quietly makes it the first one to settle down with the collection.
The repetition in "books books books" is the poem's most striking sound effect. The line is only three syllables long, and each word is a heavy, closed monosyllable, so it lands like three thuds. Read aloud, it can sound like a drone, which is also the noise a fly makes. It also works visually: the same word repeated down a shelf, one spine after another. After the longer line before it, the sudden shortness feels like a wall of volumes rising up in front of the reader.
The poem has no rhyme, and its rhythm is deliberately uneven. The first two lines run five and seven syllables, which hints at the shape of some Japanese short forms, but the pattern is dropped at once: three syllables, then five, then a final line of nine. That last line, "in the most precarious manner," is the longest and slowest, and its rhythm does what its words describe. Through the four-syllable "precarious" the line seems to teeter on the edge of a page before settling on "manner." The phrase also sounds like etiquette, as if the fly were observing a rule of formal conduct, which fits the mock-ceremonial tone set by "I sing."
The strangest and best image is "like a painted lord." The phrase recalls "painted lady," a name for a butterfly, though the poem does not say so and the connection is only my inference. Whether or not that is intended, "lord" changes everything. The fly becomes an aristocrat, perhaps a figure in a portrait, posed and decorated, perched with unearned dignity. "Painted" also brings colour into a cold, grey room and suggests stillness, as though the fly has frozen into a picture of itself. Yet a painted lord is also an artificial one, a bit of show, and that undercuts the grandeur just as the poem builds it. The tone stays affectionate and teasing at once.
The last line also quietly measures the fly against the books. The insect is tiny, light and temporary, and it balances in a "precarious" way on objects meant to last for centuries. Judging by the imagery, the poem sets fragile life against durable but inert knowledge and does not obviously choose the books. A reader might even see the poet in the fly: a small observer settling on the edge of the great things, hovering at an uncertain angle, and the poem itself is a precarious little perch of five lines.
What makes the poem worth reading is how much it does with so little. It is funny without becoming a joke, and reverent about something that normally earns no reverence. It also changes how we see a library, a place we are taught to treat with silence and awe, by letting an unlikely visitor settle on it like a king. After reading it, the next fly you notice in a quiet room may seem to be sitting there on purpose.