A walker moves through a wooded hollow and remembers a glimpse of a fisher, the dark, weasel-like animal that rarely shows itself. The place is first marked by wood nettles and by an irritable man who attacked them with a hatchet, a small burst of human anger that the speaker seems to hold at a distance. That spot then becomes "the place / of my fisher sighting," so the land is remembered through the animal rather than the argument.
The middle of the poem slows down. After the fisher disappears, the speaker lingers in "the long moment" and tries to recall its name, a nice twist, since "fishing" for a word echoes the animal's own name. The feeling is a mix of awe and a little frustration at how language lags behind wonder.
The closing lines widen out to "wilder hills / and deeper hollows," then end on the fisher's rippling gait. The mood is hushed, curious, and quietly thrilled, with the animal's movement lingering in the mind.