Seaside Sparrow Overview, All About Birds, Cornell Lab of Ornithology

Although territorial, the Seaside Sparrow often feeds long distances from the space it defends around its nest. In the tidal zone where it lives, nesting and feeding areas often are widely separated.

The Seaside Sparrow is divided into several different subspecies that look subtly different. The two most distinct forms, the endangered "Cape Sable" Seaside Sparrow and the extinct "Dusky" Seaside Sparrow were once considered separate species. The "Cape Sable" Seaside Sparrow has dark streaks on a white chest and is the palest form. The "Dusky" Seaside Sparrow was the darkest form, with a blackish back and heavy dark chest streaks.

The oldest recorded Seaside Sparrow was a male, and at least 10 years old when he was recaptured and rereleased during banding operations in South Carolina.