A speaker sits out a hot afternoon beside a tidal marsh, wanting the landscape to explain itself, and ends up being taken over by the wind instead. The poem's central idea is that understanding may come by giving yourself up to a force rather than by questioning it. It starts with a question the speaker wants answered and finishes with the speaker no longer asking at all.
The opening stanzas are all about things vanishing. At floodtide the sandbar is not simply covered, it "sinks", and the only evidence of it is "waves faltering out of rhythm". The word "faltering" is well chosen. It describes the water, but it also describes the line, which stumbles through its own uneven beat. Something hidden is known only by the disturbance it causes, and that idea runs through the whole poem. The second stanza is harsher. Currents "gnaw debris free from banks / for burial in the black mud of the marsh." The verb "gnaw" makes the water slow and animal-like, and the hard b sounds of "banks", "burial" and "black" thud downward like earth being packed over something. The landscape is erasing and burying, patiently and without comment.
Then the speaker appears, "idling" in "the pentacle of an old army tent". A pentacle is a five-pointed star, and the word has a magical ring. Perhaps the tent's shape or the pattern of its poles suggests it, but either way the speaker is cast as someone in a conjurer's circle, about to summon an answer. The tent itself is a piece of leftover human equipment, like the debris being buried outside, so the speaker is quietly placed among the things the marsh is absorbing. The wish is phrased carefully: "I would have the green heat speak". That "would have" is conditional, a hope rather than an expectation. "Green heat" mixes colour and temperature, so the heat feels like something alive in the plants. The speaker wants to know "why it flows so close under the earth", which links the heat to the water's currents and suggests that something moves beneath the visible ground here. The stanza ends with the speaker's "shadow" blurring. This is a literal heat shimmer, but it is also the first sign that the speaker's own edges are going soft, just as the sandbar's did.
The turn comes with "But the wind rising is enough". The word "enough" admits that the question will go unanswered and that this doesn't matter. The line breaks do much of the work from here. "All afternoon / it has me" is cut off from what follows by a blank space, so there is a pause in which the speaker is simply possessed. "Has me" sounds like ownership, almost like being caught. Only after that gap does the sentence continue: "thinking what a wind thinks / miles past land." The poem ends with no full stop, so the thought seems to carry on out over the water. It is also worth noticing how the solid things fall away: the sandbar sinks, the shadow blurs, and finally land itself is left behind.
The title "A Call" can be read two ways, and the poem seems to want both. The speaker has been calling on the heat to speak, but the real call turns out to be the wind's, pulling the speaker's attention outward. That reading is an inference from the text, but it fits the way the poem reverses who is doing the asking.
Formally, the poem is free verse with no rhyme and no regular metre. Its stanzas vary in length, running from three lines to two to four, then two and two, and the shape loosens as the speaker's control does. Its music comes from sound rather than pattern: the sibilance of "Floodtide sinks the sandbar", the heavy consonants of the burial lines, and the long, drifting final sentence.
The poem is significant for how much it does in so few lines. It dramatises a kind of knowing that is not analysis. The speaker never learns why the heat runs under the earth, but ends up thinking as the wind thinks, without land or explanation. The poem asks whether that counts as a better answer than the one the speaker went looking for.