This bird has relatively few remaining dark marks on the side of the breast and neck, and those that are present are either bars or ambiguous in shape because so worn. In addition, the entire underparts appear to be red. I believe this to be a Long-billed Dowitcher. Compare the Short-billed photographed same place same time, with clearcut spots on the side of the breast, and white underparts: http://www.pbase.com/image/46611111 .