Guide to North American Birds
Priority Bird
Conservation status "Dusky" Seaside Sparrow became extinct in 1987; "Cape Sable" form is localized and vulnerable, as are some other populations. Species as a whole has declined owing to destruction of coastal marshes.
Family New World Sparrows
Habitat Salt marshes. Lives in tidal marshes along coast, favoring areas with dense tall growth above level of highest tides and with openings and edges for foraging. Habitats often feature spartina, rushes, and saltgrass. In Florida, extinct "Dusky" Seaside Sparrow nested in fresh or brackish marsh in some areas, and "Cape Sable" form still does so in parts of extreme southern Florida.
No other songbird in North America is so closely tied to salt marsh as the Seaside Sparrow. Except for a few populations in Florida, it is almost never found away from tidal marshes along the immediate coast. With a patchy and disjunct habitat, this species has evolved a number of well-marked local races. One of these, the 'Cape Sable' Seaside Sparrow, was not discovered until 1918; another, the 'Dusky' Seaside Sparrow, recently became extinct despite major efforts by conservationists.

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Feeding Behavior

Forages on the ground at edge of water, and in low growth such as cordgrass and salicornia. May probe in mud or pick items from surface of vegetation.


Eggs

3-4, sometimes 2-5. Bluish white to very pale gray, with blotches of brown often concentrated at larger end. Incubation is by female only, about 12-13 days. Young: Both parents feed the nestlings. Young leave the nest about 9-11 days after hatching, but unable to fly well for at least another week. Parents may feed young for 2-3 weeks after they fledge. 1-2 broods per year.


Young

Both parents feed the nestlings. Young leave the nest about 9-11 days after hatching, but unable to fly well for at least another week. Parents may feed young for 2-3 weeks after they fledge. 1-2 broods per year.

Diet

Mostly insects, other invertebrates, and seeds. Diet varies with season and location, but major items include grasshoppers, beetles, caterpillars, spiders, small crabs, snails, amphipods, and marine worms. Also eats many seeds, especially in fall and winter, including those of cordgrass and saltbush.


Nesting

During courtship, male follows female, frequently raising his wings and singing. In non-migratory southern populations, members of pair may remain together on nesting territory all year. Nest site is in low marsh vegetation, a few inches above level of highest tides. Nest (built by female alone) is an open cup of grass, lined with finer grasses. Usually has at least a partial cover or canopy built by bird or provided by surrounding plants.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

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Migration

Many birds probably non-migratory, although some depart in fall from northernmost part of breeding range and a few spend the winter south of known breeding areas in Florida and Texas.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon

See a fully interactive migration map for this species on the Bird Migration Explorer.

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Songs and Calls

2 short, sharp notes followed by a buzzy zeeee.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
Learn more about this sound collection.