In the dry woods and still water of an October twilight, the speaker counts fifty-nine wild swans at Coole, nineteen years after he first counted them. The memory of that earlier visit is vivid: the birds rose suddenly in clamorous, broken rings. Now the same brilliant creatures make his heart sore. They seem untouched by time, still paired and full of energy, while he feels his own life has changed and grown heavier; their constancy makes his own mortality feel sharper.
By the end, their beauty carries a note of foreboding. They drift mysterious and lovely, but he wonders when they will fly away and by what other lake or pool they will please other eyes. The mood is reverent and melancholy—awe at the swans’ enduring vitality, shadowed by the speaker’s sense of his own passing. There is no resolution, only a lingering question.