Courtesy Kenn Kaufman
The Seaside Sparrow occurs from southern New Hampshire to Duval County, Florida along the Atlantic Coast. After breeding, northern populations migrate southward along the coast and winter most commonly from the Carolinas south. Formerly considered extirpated in Florida, the Cape Sable subspecies remains in three southern counties. Along the Gulf of Mexico, scattered populations breed up to the mid-coast of Texas and winter up to its southern border.
A legend for the range map to the right can be found here.
In all seasons, this sparrow occupies the wet, muddy areas of thin grassy coastal salt marsh strips, along estuaries, and in freshwater prairies in far southern Florida. The Seaside Sparrow requires open muddy areas for foraging, and vegetation tall enough to locate nests above high tides. Several species of cordgrass and salt grass are key habitat components.
With a long bill and large feet, the Seaside Sparrow can probe the mud, scratch the loose wrack, climb through dense stands of grass, and chase prey across the soft ooze exposed by the tide. These birds are fairly omnivorous and consume insects, spiders, snails, beach fleas, and worms during the breeding season. Seeds are eaten in the fall and winter. Seaside Sparrows have the ability to drink salt water.
Spring is the best time for observing Seaside Sparrows. Males sing from exposed perches, with a song that reminds some of a buzzy, faint rendition of the Red-winged Blackbird's familiar tune. In territorial disputes, males fight vigorously from the ground and up into the air. Monogamous pairs bond with complex displays, and females defend their nests from rival species, like Marsh Wrens.
Nesting begins earlier in southern populations (mid-March) and ends later in the northeastern populations (mid-July). The female sparrow builds a nest of course and fine grasses, and attaches it to a cluster of grass or a small woody plant. She lays 2 to 5 whitish eggs, splotched with brown, that hatch after about 12 days. The pair feed the chicks together. The young leave the nest in about 9 days, although they cannot fly for at least another week. Following a nest failure, pairs often re-nest, or produce a second clutch. Juvenile Seaside Sparrows form loose flocks in taller vegetation and cooperate in their mutual defense.
Seaside Sparrows appear to be residents in the south, while northern breeders leave their wintering grounds as early as mid-April. Under mild conditions, some sparrows overwinter in the Northeast, and migratory populations are faithful to their nesting sites.