Motifs are recurring symbols which support the themes or main ideas in any story. In A White Heron, the young sportsman's gun is a recurring motif.
To Sylvia, the gun represents strange emotions associated with masculinity, an area she's too young to explore but which, nevertheless, fascinates her.
Sylvia would have liked him vastly better without his gun; she could not understand why he killed the very birds he seemed to like so much. But as the day waned, Sylvia still watched the young man with loving admiration. She had never seen anybody so charming and delightful; the woman's heart, asleep in the child, was vaguely thrilled by a dream of love.
Sylvia is only nine and for her, the realm of love is still hidden in shadows. For her part, she's fascinated as well as horrified by the hunter's nonchalance in killing his animal prey. The gun, of course, is a phallic symbol, and it underlines the theme of nature versus man in the story. Sylvia's conflict is with herself: should she choose to humor the sportsman by revealing the white heron's hiding place or should she protect the birds that have given her so much joy in her young life?
In the end, Sylvia makes her decision on the side of nature. Although her heart is broken as she remembers the "sharp report" of the young sportsman's gun and the "sight of thrushes and sparrows dropping silent to the ground, their songs hushed and their pretty feathers stained and wet with blood," the author suggests that Sylvia has made the better choice. The young protagonist foregoes financial remuneration and a promising friendship with the huntsman in order to protect the beautiful white heron.
So, in the story, the gun is used as a motif to underline the theme of conflict between nature and man. Certainly, the gun can be a useful weapon when one lives in the wilderness: Sylvia's grandmother shares with the sportsman how her son, Dan, used to keep her pantry well-stocked with partridges and squirrels when he was home. However, the gun can also represent the loss of innocence. Sylvia, who doesn't understand how the sportsman can shoot the birds he purports to love, must suddenly begin to contemplate how nature fits into the larger story of humanity.