| a species of sparrow, Ammospiza maritima, existing in two subspecies, one (Cape Sable seaside sparrow) having dark olive-drab plumage with a lighter breast and underbelly, and the other (dusky seaside sparrow) having bold black and white markings on the breast and underbelly: the dusky seaside sparrow is almost extinct. |
| seaside sparrow n. A small sparrow (Ammospiza maritima) of the Atlantic coast of North America. |