Contributors: John E. Cely and Dennis M. Forsythe
Taxonomy and Basic Description
The seaside sparrow is a geographically variable species within the order Passeriformes (perching birds), family Emberizidae (AOU 1998).
The seaside sparrow is olive-gray to olive-brown, has a relatively long bill and short, sharp tail. The back and breast are streaked, but not always conspicuously so. The facial pattern is distinctive with the supraloral spot and supercillium yellow from above the eye to the bill and a pale sub-moustachial stripe. The malar stripe is dark and the throat pale. These birds are about 12.5 to 15 cm (5 to 6 inches) in length and weigh about 24.2 g (0.85 ounces). Males are slightly larger with sexes similar in coloration (Rising 1996).
The seaside sparrow is designated as a high priority landbird by South Carolina Partners in Flight (PIF) and South Atlantic Migratory Bird Initiative (SAMBI). A Florida subspecies, the dusky seaside sparrow, A. m. nigrescens, is now extinct, while the Cape Sable seaside sparrow (A. m. mirabilis) is critically endangered.
POPULATION DISTRIBUTION AND SIZE
This species occupies a very narrow strip of salt and brackish marsh along the outer coastal plain “tidewater region.” Post and Gauthreaux (1989) gives its status as “resident, fairly common in summer and common in winter. Apparently, winter numbers are augmented by migrants from further north.” Typically, the breeding birds belong to the dark subspecies A. m. macgillivraii while additional wintering birds belong to the lighter subspecies A. m. maritimus. This species has also been found nesting in coastal marshes as far inland as the town of Hanahan near Goose Creek, South Carolina.
Because the seaside sparrow is poorly sampled by the BBS, due to its inaccessible habitat, there are no trend figures or objectives for South Carolina.
HABITAT AND NATURAL COMMUNITY REQUIREMENTS
The seaside sparrow is found exclusively in salt and brackish marshes consisting of cord grasses (Spartina spp.), true rushes (Juncus spp.) and bulrushes (Scirpus spp.). Post and Gauthreaux (1989) note that in order to avoid extreme tidal fluctuations, seaside sparrows move up the estuaries to nest. Significant populations occur in black needle-rush marshes at the Tom Yawkey Wildlife Center, Cape Romain National Wildlife Refuge, and other areas featuring extensive coastal marsh.
While the seaside sparrow has one of the most restrictive breeding ranges of any passerine, its habitat has one of the most stringent regulatory protections of any type in the country. Prior to the enactment of tidelands protection, some seaside sparrow populations had been severely impacted by salt marsh ditching and possibly pesticide spraying for mosquito control. Post and Greenlaw (1994) suggest the species can serve as an indicator of coastal marsh ecological integrity.
Post and Greenlaw (1994) note that southern populations, such as found in South Carolina, suffer high nest predation rates from rodents.
Most seaside sparrow research has been conducted in the northeast and Florida. Currently, demographic research on the seaside sparrow is being conducted at Stono and Headquarters Islands. However, basic information on demographics, nesting habitat, site fidelity, predation and other biological parameters are needed. Monitoring techniques should be a high priority, as the species does not lend itself to traditional sampling methods.
Other than habitat protection measures through regulation, acquisition, and easements, no conservation/research measures specifically directed to seaside sparrows have been enacted.
Maintain current regulations and statutes protecting tidal wetlands.
Where possible, restore ditched and altered marshes.
Control predators in areas of high seaside sparrow nest predation.
Support efforts to collect basic information on demographics, nesting, habitat, site fidelity, predation and other biological parameters.
Inform the public and constituents about research and survey results and habitat needs, as this species is little known to the general public.
MEASURES OF SUCCESS
Stabilization or increases in populations would be considered successes. This may be accomplished through proper monitoring techniques and habitat protection.
The American Ornithologists’ Union. 1998. Check-list of North American Birds, 7th edition. American Ornithologists’ Union. Washington, D. C.
Post, W. and S.A. Gauthreaux. 1989. Status and distribution of South Carolina birds. Contributions from the Charleston Museum 18. 83 pp.
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. The Academy of Natural Sciences. Philadelphia, Pennsylvania.
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, California. 369 pp.