Cape Sable seaside sparrows are small birds about 13 centimeters or 5 inches long. Dorsally, they are dark olive-gray with olive-brown on the tail and wings. The greenish cast on the nape is generally difficult to detect. Ventrally, adults are light gray to almost white with dark olive-gray streaks on the breast and sides. Occasionally, the breast streaks converge forming a diffuse central spot. There is a dark whisker on either side of the white throat. These sparrows have yellow lores, brown eyes, and a gray ear patch behind the eye which is fringed by a dark line. There is a small patch of yellow on the edge of the wing. No sexual differences in the plumages are obvious. A report that represents a literature review of science conducted on the Cape Sable Seaside Sparrow (Benscoter, A.M., S.M. Haider, K.G. Guilbeau, and S.S. Romañach. 2021. Knowledge synthesis of Cape Sable Seaside Sparrow science. Report to the U.S. Fish and Wildlife Service. 68 pp.) can be found at this link: https://ecos.fws.gov/ServCat/Reference/Profile/139083(please copy and paste link)