Evening is the oldest subject in poetry, and "Harbor Night" does not try to dodge that fact. What it does instead is look at a single waterfront at the moment work gives way to sleep, and let the whole scene quietly lower its voice. Three stanzas, three movements: first the tired sounds of the day, then the small lights and the one stubborn bird of the early dark, and finally a comic, strangely moving image of the sun leaving town like a man who has spent his money and his welcome.
The opening line sets the tone with a small surprise. We expect people to grow tired at day's end, but here "even the gulls" do, as if exhaustion were so total it had reached the creatures usually thought of as noisy and tireless. Then the human labor enters: "the young stevedores' last weary cries." The word "young" matters. These are not worn-out old men but dockworkers still in the first decades of life, and their fatigue carries a faint pathos. Their shouts do not simply stop; they "drift over the harbor in forgotten music." Work noise becomes music only when it is far enough away and quiet enough to be heard that way, and "forgotten" suggests a tune no one is listening to anymore. Against this fading, the tide moves the other way: "the new tide comes in with quickening sighs." Day winds down while the water speeds up, and the sigh, a human, weary sound, is lent to the sea.
The second stanza turns from sound to light, and the imagery becomes delicate. Lanterns have "eyelids," and their glow "flutter[s]" like "slow fireflies" along a "silent pier." The comparison does two jobs at once: it makes the lights alive, blinking sleepily like the harbor itself, and it slows them down, since fireflies are quick and these are "slow." Then comes the poem's one sharp disruption. A whippoorwill in "drowsy willow trees across the river" strikes "one high note and hold[s] it, stubborn and shrill." Everything else in the poem is dimming, softening, drifting. This bird is the exception, a single piercing line drawn across the hush. "Stubborn" is the perfect word for it, and it quietly echoes the tiredness of the first stanza by contrast: the gulls give up, the bird refuses.
The final stanza gives the poem its memorable idea. The sun becomes "an old drunken seaman" who, "deserting the harbor," "pockets his gold and goes / to some far salty tavern beyond the night." The conceit is neat because it grows naturally out of the setting. A harbor is full of sailors and taverns, so the sunset's gold light turns into a sailor's coins, and the horizon becomes a place to carouse. There is humor in it, a shambling, slightly rascally figure stumbling off with his winnings. But the last line shifts the mood: the tavern has "a dark address nobody knows." The sun's departure ends in mystery, and the image of a man heading somewhere unknowable carries a faint shadow of loneliness.
Formally, the poem is gentle and unshowy. Stanzas rhyme in alternating patterns, with "ending" and "sighs" followed by "music" and "sighs," and "whippoorwill" and "shrill" closing a pair, though in the final stanza the rhymes ("sun," "goes," "night," "knows") loosen into something looser and more conversational. The lines are long and lilting, and they ease along on soft consonants and open vowels, so that the reader's own pace slows with the evening. The effect is of a lullaby that has been given a sailor's slouch.
What makes the poem worth reading is its tact. It never announces that dusk is peaceful or sad; it lets a tired gull, a flickering lantern, and one unreasonable bird do that work, and then it hands the sun a personality. In a few lines it turns a familiar sunset into a small story, and it leaves us looking at the dark with the same question the sailor's tavern raises: where does the day actually go?