I would want to answer this question by pointing towards the way in which this excellent book is actually in part an elegy. An elegy is a term that is used to mean a kind of funeral song or poem that praises a dead person. This suggests that this text is actually rather ambiguous in terms of its mood. It praises the Kiowa and their pride, fighting abilities and sense of freedom. However, at the same time the text also grieves about the way in which their religion has been assaulted and their culture has been lost. This ambivalence also could be said to impact the attitude or mood of this text. There are certainly numerous images of light and life and descriptions of nature that capture a joyful spirit, however, there are also images of darkness and death such as the dark mist, and the cemetery, that create a much more sombre and sad mood. Consider the following excerpt as an example of how the text creates this ambivalent mood:
The long yellow grass on the mountain shone in the bright light, and a scissortail hied above the land. There, where it ought to be, at the end of a long and legendary way, was my grandmother's grave. Here and there on the dark stones were ancestral names. Looking back once, I saw the mountain and came away.
Note the way that the setting of the narrator's grandmother's grave and the other "ancestral names" that adorn the "dark stones" are coupled with the "bright light" that lights up the "yellow grass." The mood might therefore be described as being bittersweet as there is both joy and sadness present in the text.