secretcanyon,
I'm certainly no expert on these things and know but little about the meaning and workings of the native American culture and ways. In my uneducated opinion, the painted headdress looks to surely be Apache in nature, you can tell by the black mask attached to it, classic of the Nde spiritual ceremonies. The maker undoubtedly painted the headdress himself to symbolize something once of great importance in his life. The site, staged the way it is, appears to be not an offering so much as a funeral. Not a mortal death but a spiritual death. The maker having lost something very close to him that will never return. Something that was a part of his spirit.
The mountain spirits hide their ceremonial clothes and masks in secret caves or shelters. No one else would dare to wear or put on these articles or even touch them. When a mountain spirit died or became to old or sick to perform the ceremonies, his mask, headress and clothes were sometimes placed as this, signifying a spiritual passing. It makes me think the maker of the site had lost a part of him and was saying goodbye to it.
Of course, this is only my personal opinion and I am not an expert on the matter.
Matthew K. Roberts