[2] The oldest record of seaside sparrow was an individual male which was at least 10 years old when recaptured and re-released during the banding operations in South Carolina.

The nest is an open cup usually built in the salt marsh on tidal reeds and spartina grasses.

[citation needed] Northern birds most often migrate farther south along the eastern coast of the United States.

[citation needed] The song is a raspy buzz that closely resembles a distant red-winged blackbird.

The small isolated population that is near Corpus Christi, Texas, south to the Rio Grande and the sennetti subspecies may also have risk to endangered,[4] those were formerly considered a separate species.