Seaside Sparrow

Ammodramus maritimus

(c) Roger Everett
  • EMBERIZINAE
  • Sparrows, Buntings, Towhees, Longspurs
  • Passeriformes
  • Sabanero marino
  • Bruant maritime
Introduction
A shadow in the grass, the Seaside Sparrow is a small, dark songbird with a husky voice, living exclusively in or directly next to salt marshes of the eastern seaboard and Gulf Coast. The success of these medium-sized sparrows often indicates the health of that fragile habitat. With nine recognizable subspecies, these birds have a complex history. As we reshape their habitat, Seaside Sparrows become increasingly scarce in some parts of their range; one subspecies, the Cape Sable Seaside Sparrow, is now endangered, and another, the Dusky Seaside Sparrow, is now extinct.
Appearance Description
In all subspecies, the Seaside Sparrow is a chunky songbird with a substantial bill. On average, the bird weighs .81 ounces, and measures 6 inches in length, with a wingspan of 7.5 inches. Under most conditions, the Seaside Sparrow's plumage appears dark and blurry. The throat is whitish and the folded wings brownish, but the back and under-parts are olive gray with indistinct streaks. In good lighting, a yellow patch may be visible in front of the eye. The Cape Sable Seaside Sparrow generally has more distinct streaks.
Range Map
Courtesy Kenn Kaufman
Range Distribution
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.
Habitat
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.
Feeding
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.
Reproduction
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.
Migration
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.
CBC Graph
Graph Legend
Annual Population Indices
  • 110,000
  • 110,000
  • Endangered (Cape Sable Seaside Sparrow)
  • restricted distribution, low population size
Population Status Trends
The loss of the Dusky Seaside Sparrow, sometimes considered a separate species, indicates the profound impact that human activities have on wetland species. Although some Seaside Sparrow populations in the Northeast may be increasing and expanding their range into New Hampshire, Christmas Bird Count data indicate declines in other populations. The Cape Sable Seaside Sparrow resides only in Florida's Everglades and Big Cypress National Preserve, and continued alteration of the habitat there threatens this special population.
 
An explanation of the Annual Population Indices graph displayed to the right can be found here.
Conservation Issues
Poised between land and sea, the Seaside Sparrow has no margin for error. The sparrow's habitat has been disturbed by ditching to combat mosquitoes, and by water impoundment. Non-native and native plant species more suited to dry conditions produce less food for the sparrows during the critical breeding season. For foraging and nesting, a diversity of micro-habitats with native grasses and muddy patches must be actively protected, via controlled burning during the wet season, allowing natural tidal flow, and maintaining appropriately high water levels, which also discourage ground predators.
 
Despite concerted efforts, conservation groups and the U. S. Fish and Wildlife Service (USFWS) were unable to prevent the extinction of the Dusky Seaside Sparrow,. America lost this unique bird in 1987, when the last male died in captivity. A similar fate for the Cape Sable Seaside Sparrow may be avoided by implementing USFWS's Remedial Action Plan, which focuses on habitat rehabilitation.
What You Can Do
Observe Seaside Sparrows in their native habitat. During breeding season, take a wildlife tour to a local salt marsh along the east coast of the United States and watch for Seaside Sparrows.
 
Respect the Seaside Sparrow's muddy, wet habitat during the breeding season: Avoid trampling through uncut marsh grass, and steer boats well away from the grassy edges of marshes, estuaries, and riverbanks.
 
Support local efforts to reduce boat wakes along marshes, estuaries, and riverbanks.
 
Join a local conservation group to limit development in critical wetlands, and to limit access to these wetlands during breeding season. Conservation easements can be an effective tool for managing land to benefit Seaside Sparrows, especially with controlled burns and water level management.
 
For actions you can take, including Audubon activities, please visit our resources page.
More Information
Visit our resources page for more information about this species.
Natural History References
Post, W., and J. S. Greenlaw. 1994. Seaside Sparrow (Ammodramus maritimus). In The Birds of North America, No. 127 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
 
Rising, J.D. 1996. A Guide to the Identification and Natural History of the Sparrows of the United States and Canada. Academic Press. San Diego, London, New York, Boston, Sydney, Tokyo, Toronto
 
Sibley, David Allen. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York.
Conservation Status References
Post, W., and J. S. Greenlaw. 1994. Seaside Sparrow (Ammodramus maritimus). In The Birds of North America, No. 127 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
 
Rising, J.D. 1996. A Guide to the Identification and Natural History of the Sparrows of the United States and Canada. Academic Press. San Diego, London, New York, Boston, Sydney, Tokyo, Toronto.
 
Sibley, David Allen. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York.