"Heart of Autumn" is a poem about death, the poet's own anticipated death, and it is also a poem of exultation in life. The form is a looser quatrain than his earlier poems, without rhymes, but it has a strong and unmistakable rhythm that is in accord with the central image of the poem, that of the wild geese flying southward in autumn, a familiar sight to Warren from his Kentucky boyhood—though it might just as well have been seen on the farm in Connecticut where he lived during most of his later years. It is an image of flight, but not of fleeing from something menacing, as in his earlier Fugitive poems; rather it is a flight toward something attractive, "toward sunset," clearly a metaphor for death. Warren is picturing the soul's imagined flight into eternity, for which he had been practicing throughout his long career by writing poetry. As he once put it, poetry for him was a "prayerful state" in which much time is spent simply in being passive, waiting for inspiration to come. In the poem, he watches the geese following their "path of pathlessness, with all the joy / Of destiny fulfilling its own name," and he thinks, "I have known time and distance, but not why I am here," and yet this difference between nature's instinctive sense of direction and man's indeterminate fate does not leave him feeling desolate or lonely or separated from nature. The "heart of autumn" is finally the poet’s own heart, mortal yet exultant, thrilling to the "imperial utterance" of the wild geese honking in the sky, and responding with "a fierce impulse / To unwordable utterance": he, too, is rising up and singing, "Toward sunset, at a great height."