Sylvia imagines all the treasures that could be bought with the $10 offered by the ornithologist to whomever can show him the white heron.
In the morning, she climbs the great pine tree, believing that she will be able to see the nest of the heron. Sylvia is right; she discovers the heron's secret. She wonders what the stranger will think when she leads him to the nest.
Sylvia, however, recognizes that the hunter is an adversary to nature. He just wants to kill the bird and add it to his collection. Even though she has taken a liking to the sportsman, she "cannot tell the heron's secret and give its life away." Sylvia, herself, is very connected with nature.
The guest leaves disappointed. This is how the story ends: "Were the birds better friends than their hunter might have been, -- who can tell? Whatever treasures were lost to her, woodlands and summer-time, remember! Bring your gifts and graces and tell your secrets to this lonely country child!" Sylvia can, after all, keep nature's secrets.