Saltmarsh Sharp-tailed Sparrow

Ammodramus caudacutus

(c) John Cassady
  • EMBERIZINAE
  • Sparrows, Buntings, Towhees, Longspurs
  • Passeriformes
  • Sabanero de cola aguda
Introduction
On the edge of the Atlantic coast, the Saltmarsh Sharp-tailed Sparrow lives in a shrinking ribbon of grassland. This bright-faced songbird usually prefers to run or clamber through the marsh, rather than to fly over it. The Saltmarsh and Nelson's Sharp-tailed Sparrows were considered a single species until 1995. The separation into two species focused attention on the plight of the Saltmarsh Sharp-tailed Sparrow's habitat and the need to better understand its biology.
Appearance Description

At 5.25 inches long, Saltmarsh Sharp-tailed Sparrows weigh .67 ounces with a 7-inch wingspan. A satisfying look at a Saltmarsh Sharp-tailed Sparrow requires devotion and magnification. This small, compact perching bird often appears flat-headed, with no neck. The plumage is complex and bold. Thick orange-yellow lines form an inverted triangle around each gray ear and dark eye. Behind the eye, a brown line pierces this ochre color to connect the eye to the gray nape. A dark cap and whitish throat frame this pattern. Distinct among the brown and black streaks of the upper parts are four jagged, white streaks. The lower parts are mostly whitish, with a little warm color washed over the thin, dark streaks of the breast.

Range Map
Courtesy Kenn Kaufman
Range Distribution
Confined to coastal marshes, the Saltmarsh Sharp-tailed Sparrow breeds from southern Maine just into North Carolina (Pea Island). Its populations are most dense in the marshes of Long Island south to the Delmarva Peninsula. The Saltmarsh Sharp-tailed Sparrow's range overlaps with its close relative, the Nelson's Sharp-tailed Sparrow, with which it may interbreed, from northeastern Massachusetts through the end of its range in southern Maine. This small sparrow winters coastally from Maryland south to the Atlantic mid-coast of Florida. It rarely occurs on Florida's Gulf Coast.
 
A legend for the range map to the right can be found here.
Habitat
For breeding, Saltmarsh Sharp-tailed Sparrows need large maritime wetlands around estuaries and barrier islands. Course grasses like spartina and blackgrass dominate these open salt marshes, leaving muddy spaces between the grass tufts. The sparrows winter in similar habitat—sometimes in the same area.
Feeding
The Saltmarsh Sharp-tailed Sparrow forages actively through grasses and over the wet marsh floor. Hunting by sight, this sparrow walks, runs, hops, and jumps after prey. Its breeding season diet consists of small crabs, small mussels, and adult and immature insects—including beach fleas, beetles, flies, and moths. As annual plants ripen in the marsh, the sparrow's diet shifts to include seeds from cordgrass, dandelions, saltbush, and smartweed. The Saltmarsh Sharp-tailed Sparrow climbs grass stems to pull seeds from their husks.
Reproduction
The Saltmarsh Sharp-tailed Sparrow's breeding behaviors are remarkable and unusual. Males assemble on the breeding grounds but do not defend territories or bond with arriving females. Females are attracted by songs and chased by males in a competitive scramble to mate. Females assume all nesting and chick-rearing tasks. Saltmarsh Sharp-tailed Sparrows appear to time their nesting to avoid high tides, which can kill eggs.
 

The female usually builds a grassy nest attached to grass stems over mud or water, and covered by loosely intertwined grass blades. She lays two to six greenish to bluish eggs, densely speckled with browns. The young hatch in about 12 days. Fed insects and small crustaceans, the naked, helpless chicks develop quickly, leaving the nest in about ten days to hide in the grass. Two to three weeks later, the independent young flock with other juvenile Saltmarsh Sharp-tailed Sparrows. Most females south of Massachusetts will then raise another brood.

Migration
The timing and behavior of Saltmarsh Sharp-tailed Sparrow migration has not been well separated from that of the Nelson's Sharp-tailed Sparrow. The Saltmarsh Sharp-tailed Sparrow withdraws from its breeding range almost entirely and migrates short to medium distances. During migration and winter, this sparrow may be found in groups.
  • 250,000
  • 250,000
  • globally vulnerable
Population Status Trends
Little data has been collected on this "new" maritime sparrow. Christmas Bird Counts from 1997 to 2005 record significant fluctuations. Wildlife managers infer current and future population declines based on significant habitat losses along the Eastern coastline. This sparrow is a "species of conservation concern" for the U. S. Fish and Wildlife Service, as well as in the states of Georgia, Maryland, New York, South Carolina, and Virginia.
Conservation Issues
The Saltmarsh Sharp-tailed Sparrow's limited range and shrinking habitat concern conservationists. Several east coast states have lost 25 to 73% of their total wetlands between 1780 and 1980. Many of the Saltmarsh Sharp-tailed Sparrow's remaining coastal wetlands are in poor health. The 2005 National Coastal Condition Report II found poor habitat conditions from New England to Maine. One year later, the U.S. Department of the Interior reported a loss of over 28,000 acres of intertidal wetlands occurring from 1998 to 2004 across the country.
 
On top of habitat losses caused by commercial development, the Saltmarsh Sharp-tailed Sparrow is impacted by toxic environments and the invasion of exotic plant species. In 2006, significant levels of mercury were reported in the blood of Saltmarsh Sharp-tailed Sparrows breeding in Maine. Marshes invaded by plants like phragmites, ditched to lower water levels, or shrunk by developers become unsuitable for nesting, and may be abandoned by this small songbird. Extensive, healthy marshlands dominated by grasses are essential for the Saltmarsh Sharp-tailed Sparrow.
What You Can Do
Look for the Saltmarsh Sharp-tailed Sparrow by visiting the edges of marine grasslands. Be careful to avoid their fragile habitat. Use an approved access road, like the one provided by the Parker River Wildlife Refuge on Plum Island, east of Newburyport, Massachusetts. 
 
Share your thoughts on wetland conservation with your elected representatives.
 
Become involved in local wetland restoration efforts. The Environmental Protection Agency offers programs, instructional materials, grants, and helpful links. Visit their "Wetland Restoration" website.
 
Take a break from winter, and join a Christmas Bird Count along the southeastern coast of the United States. Your observations will add to the knowledge of this "new" species.
 
For more 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
Gjerdrum C., Elphick C. S., and Rubega M. "Nest site selection and nesting success in salt marsh breeding sparrows: The importance of nest habitat, timing, and study site differences." The Condor 107:4 (2005) p. 849-862.
 
Greenlaw, J. S. and J. D. Rising. 1994. Sharp-tailed Sparrow (Ammodramus caudacutus). In The Birds of North America, No. 112 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
 
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, New York. 2000.
Conservation Status References
Benoit, L.K.; Askins, R.A. "Impact of the spread of phragmites on the distribution of birds in Connecticut tidal marshes." Wetlands 19:1 (Mar 1999) 194-208.
 
Dahl, T.E. 2006. Status and Trends of Wetlands in the Conterminous United States 1998 to 2004. U.S. Department of the Interior; Fish and Wildlife Service, Washington, D.C. 112 pp.
 
Erwin, M.R., G.M. Sanders, and D.J. Prosser. "Lagoonal marsh morphology at selected northeastern Atlantic coast sites of significance to migratory waterbirds." Wetlands 24:4 (2004) 891-903.
 
Greenlaw, J. S. and J. D. Rising. 1994. Sharp-tailed Sparrow (Ammodramus caudacutus). In The Birds of North America, No. 112 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
 
Summers, Kevin, et al. National Coast Report. U. S. Environmental Protection Agency, Office of research and Development, Office of Water. December 2004.
 

Shriver W. G., D. C. Evers, T. P. Hodgman, B. J. MacCulloch, R. J. Taylor. "Mercury in Sharp-Tailed Sparrows Breeding in Coastal Wetlands." Environmental Bioindicators 1:2 (April-June 2006) p. 129-135. Only abstract available.