Seaside Sparrow Habitat Model
go to: USFWS Gulf of Maine Watershed Habitat Analysis
go to: Species Table

Draft Date:
October 2002

Species:
Seaside sparrow, Ammodramus maritimus.

Use of Study Area Resources:
Reproduction.  There are several subspecies; the nominate subspecies breeds "... Along the Atlantic coast from New Hampshire to extreme ne. Florida..." (Post and Greenlaw 1994), occurring as small, localized populations in salt and brackish marshes. Other subspecies occur in south Florida interior marshes, and along the Gulf coast from west-central Florida to Texas.  Birds breeding in New England probably winter along the se. Atlantic coast (Post and Greenlaw 1994).

Habitat Requirements:
Cover. "Optimal habitat is found in unaltered marshes with expanses of medium-high cordgrass with a turf of clumped, residual stems. Especially suitable are spots not subject to extreme flooding that have open muddy areas for feeding" (Greenlaw et al. 1992, Post and Greenlaw 1994). "Most breeding populations require nest sites above spring [high] tides, and openings in vegetation, e.g., pools and creek edges, where birds can forage on open mud and at bases of rooted vegetation... Optimal habitat contains contiguous nesting and feeding sites... Dense vegetation such as salt meadow grass is little used" (Post and Greenlaw 1994). "HIgh marshes provide marginal sparrow habitat" (Reinert et al. 1981, in Post and Greenlaw 1994).

In Massachusetts Marshall and Reinert (1990) found early season nests mostly in persistent vegetation; late season nests were placed in newly grown, irregularly flooded Spartina alterniflora. Nesting occurred more commonly along tidal creeks and ditches than in high marsh. Seaside sparrows tended to rapidly re-nest when nests were destroyed during spring tides; such secondary nesting usually was successful since fledging occurred before the next spring tide events.

Area.  Mean territory size in a Massachusetts marsh was about 4000 m^2. In general, large marshes are preferred over small areas of remnant marsh (Greenlaw et al. 1992).

Foraging. Seaside sparrows often feed far from a defended territory (Post and Greenlaw 1994), particularly in drained marshes. "Smooth cordgrass has a higher concentration of arthropods... than do other salt marsh plants...  In the breeding season seaside sparrows feed on adult and larval insects, spiders and spider egg cases, amphipods, molluscs, and marine worms" (Post and Greenlaw 1994). Greenlaw (1992) also has seen them eating cordgrass seeds.

Limiting Factors. Tidal and weather-related flooding is a common cause of nest failure, especially for northern populations (Post et al. 1983, Marshall 1986, Marshall and Reinert 1990). Predators include northern harrier, short-eared owl, crows, rats, and occasionally snakes (Post and Greenlaw 1994). Ditching eliminates preferred foraging patches, and may allow invasion by shrubs and exotic vegetation, with little habitat value for this species (Post and Greenlaw 1994).

Model:
Breeding Bird Atlas (BBA) data for Maine, New Hampshire and Massachusetts were used in delineating the range of seaside sparrows within the study area. We selected all polygons of USDA Forest Service Ecological subunits (Keys et al. 1995) in which these sparrows were known to occur. Habitat mapping then was restricted to these areas; although breeding occurs only as far north as Massachusetts and New Hampshire, the Ecological subunits extended into Maine.  We regarded the latter as having 'potential' for an extension of nesting activities.

Nesting habitat was mapped by selecting estuarine intertidal marsh (see table, below) within the range of the sparrow. We scored as 'optimal' (1.0) those marsh patches (and the immediately adjacent mudflats) intersecting BBA blocks having sparrow nesting.  Other patches (and adjacent mudflats) in Massachusetts and New Hampshire were scored 0.7, and in Maine were scored 0.3.

NWI Designations (wetlands only)	Cover Types	Cover Suitability (0 - 1 scale)
	Upland deciduous forest
	Upland coniferous forest
	Upland mixed forest
	Grassland
	Upland scrub/shrub
	Cultivated
	Developed
	Bare ground
PEM, L2EM	Lake/pond, emergent vegetation
PFOcon	Palustrine forest, conifer
PFOdec	Palustrine forest, deciduous
PSSdec	Palustrine scrub shrub, deciduous
PSScon	Palustrine scrub shrub, conifer
PAB, L2AB	Lake/pond, aquatic vegetation
L1UB, PUB	Lake/pond, unconsolidated bottom
L2US	Lake, unconsolidated shore
L2RS	Lake, rocky shore
R1UB	Riverine subtidal unconsolidated
Rper	Riverine perennial
E1AB	Estuarine subtidal vegetated
E1UB	Estuarine subtidal unconsolidated bottom
E2AB	Estuarine intertidal algae
E2EM	Estuarine intertidal emergent	1.0*
E2RS, R1RS	Estuarine, tidal river rocky shore
E2SS	Estuarine intertidal shrub
E2US	Estuarine intertidal unconsolidated shore	1.0**
M1AB	Marine subtidal vegetated
M1UB	Marine subtidal unconsolidated bottom
M2AB	Marine intertidal algae
M2RS	Marine intertidal rocky shore
M2US	Marine intertidal unconsolidated shore
NOTES	* if  patch contacts 'probable' or 'confirmed' BBA block ** if within 30 m of marsh habitat

Sources:

Greenlaw, J.S., G. Hammerson, and D.W. Mehlman. 1992. Species Management Abstract: Seaside Sparrow (Ammodramus maritimus). THE NATURE CONSERVANCY, 4245 North Fairfax Drive, Suite 100, Arlington, VA 2220; http://www.conserveonline.org/2001/05/m/en/nstsp.doc downloaded 10/01. 

Greenlaw, J.S. 1992. Seaside sparrow, Ammodramus maritimus. Pages 211-234 In Schneider K.J. and D.M. Pence (eds.) Migratory Non-game Birds of Management Concern in the Northeast. USDI Fish and Wildlife Service, Region 5, Newton Corner, MA. 400 pp.

Marshall, R. M., and S. E. Reinert. 1990. Breeding ecology of seaside sparrows in a Massachusetts salt marsh. Wilson Bull. 102:501-513.

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, and The American Ornithologists' Union, Washington, D.C.