The tone of “A White Heron” is a reverent and compassionate one. The narrator clearly has a love for nature the way that Sylvia does, and it comes across in the many moments where they describe nature with rich imagery. The narrator also has a lot of compassion and care for Sylvia, turning into a sort of cheerleader for her in moments like the following (when Sylvia is at the top of the old pine tree):
Now look down again, Sylvia, where the green marsh is set among the shining birches and dark hemlocks; there where you saw the white heron once you will see him again; look, look! a white spot of him like a single floating feather comes up from the dead hemlock […] And wait! wait! do not move a foot or a finger, little girl, do not send an arrow of light and consciousness from your two eager eyes, for the heron has perched on a pine bough not far beyond yours, and cries back to his mate on the nest and plumes his feathers for the new day!
In this passage, the narrator directly addresses Sylvia, excitedly encouraging her to locate the white heron for which she has been searching. The narrator moves from an observer of the story to actively supporting Sylvia in her quest, telling her to “look! look!” and “wait! wait!” and helping her to locate the heron while using a supportive tone.
The narrator’s reverent tone also comes across in this passage, as they describe how the heron looks like “a single floating feather com[ing] up from the dead hemlock.” Their joy of witnessing the heron simply “plum[ing] his feathers for the new day” also demonstrates their deep love of nature, which they are trying to inspire readers to feel as well.