Nelson's Sharp-tailed Sparrow Habitat Model
go to: USFWS Gulf of Maine Watershed Habitat Analysis
go to: Species Table

Draft Date:
October 2002

Nelson's sharp-tailed sparrow, Ammodramus nelsoni. Relationships of the sharp-tailed sparrows were discussed by Greenlaw (1993); this species has been regarded as distinct from A. caudacutus (which also occurs in the study area) only since1995 (Dechant et al. 2001).

Use of Study Area Resources:
Reproduction.  Nelson's sharp-tailed sparrow occurs in the mid-west (northeastern Montana, North Dakota, and northeastern South Dakota, east to northwestern Minnesota, and adjacent Canadian provinces (Dechant et al. 2001).  It also  ranges to ..."southeastern Quebec, Prince Edward Island, and Nova Scotia south to southern Maine..., and winters in the "...mid- to south Atlantic coast and Gulf coast of the U.S" (from Dechant et al. 1999).  Nelson's sharp-tailed sparrows also are observed at Parker River National Wildlife Refuge, Massachusetts, apparently the southern limit of their New England range (U.S. Fish & Wildlife Service 1999).

Habitat Requirements:
Cover. In the mid-west "...Nelson's Sharp-tailed Sparrows prefer freshwater wetlands with dense, emergent vegetation or damp areas with dense grasses... Suitable habitat includes fens, wet meadows, peatlands, lake margins with emergent cattails (Typha), native prairie, idle fields, and planted cover..." (Dechant et al. 2001). Nelson's sharp-tailed sparrow also uses brackish marshes along the coast (Dechant et al. 1999), consisting of "saltmarsh cordgrass, saltmeadow grass, and blackgrass" and the adjacent cattail, reed, and marsh elder (Greenlaw and Rising 1994). Tom Hodgman, MDIFW, (Maine Department of Inland Fisheries and Wildlife, pers. com.) observed that A. nelsoni tends to occur further up coastal rivers and marshes than A. caudacutus in Maine, often in tidal freshwater wetlands. Montagna (1942) also made this observation for what was then A. caudacutus subvirgatus.

"Nests are built on or slightly above the ground in damp areas among emergent vegetation..." (Dechant et al. 2001). On the Atlantic coast, Montagna (1942) observed them nesting very near upland grassland nesting birds, such as grasshopper and Henslow's sparrows.

Area Requirements: "In northern Minnesota, the average wetland size used by Nelson's Sharp-tailed Sparrows was 130 ha (range was from 15 to 250 ha)... In southcentral North Dakota, Nelson's Sharp-tailed Sparrows occurred on wetlands ranging in size from 5.0 to 6.4 ha (Krapu and Green 1978). "(from Dechant et al. 2001). However, A. nelsoni occurrences from an extensive 1997-1999 Maine survey (MDIFW, Tom Hodgman, unpublished) were in marsh patches as small as about 0.2 ha, within larger marsh complexes fragmented by stream channels.

Foraging. Sharp-tailed sparrows feed almost exclusively on insects, spiders and small invertebrates during the breeding season, switching to seeds of grasses and other plants in the fall and winter as other prey become less available (Greenlaw and Rising 1994). They feed on the ground in dense grass, at the edges of pools and pannes, and in patches of wrack (Greenlaw and Rising 1994).

Limiting Factors. Flooding is the most common cause of nest failure. Predators include northern harrier, short-eared owl, crows, rats, red fox, raccoon, and occasionally snakes (Greenlaw and Rising 1994).

Breeding Bird Atlas (BBA) data for Maine, New Hampshire and Massachusetts were used in delineating the range of Nelson's sharp-tailed sparrow within the study area. Because these data were collected before A. caudacutus was 'split', the blocks indicate the combined distribution of both species. However, the A. nelsoni occurrences from an extensive 1997-1999 survey (MDIFW, Tom Hodgman, unpublished), agreed well with the BBA maps in Maine.  Therefore, the BBA blocks in New Hampshire and the Parker River Refuge in Massachusetts were accepted at the southern end of the sparrow's range. The overall range was delineated by including all 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.  

Nesting habitat was delineated by selecting estuarine intertidal marsh (see table, below), and also palustrine emergent marsh that was contiguous to estuarine wetlands or waters, within the breeding range of the sparrow. The MDIFW survey data were overlaid on the selected salt and fresh tidal marsh features. We scored  as 'optimal' (1.0) those marsh patches in which Nelson's sharp-tailed sparrows were observed; the other patches were scored 0.7.
NWI Designations
(wetlands only)
Cover Types Cover Suitability
(0 - 1 scale)
Upland deciduous forest
Upland coniferous forest
Upland mixed forest
Upland scrub/shrub
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


E2RS, R1RS Estuarine, tidal river rocky shore
E2SS Estuarine intertidal shrub
E2US Estuarine intertidal unconsolidated shore
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 contiguous with tidal waters or wetlands


Dechant, J. A., M. L. Sondreal, D. H. Johnson, L. D. Igl, C. M. Goldade, P. A. Rabie, and B. R. Euliss. 2001. Effects of management practices on  grassland birds: Nelson's Sharp-tailed Sparrow. Northern Prairie Wildlife  Research Center, Jamestown, ND. Northern Prairie Wildlife Research Center  Home Page. (Version 17FEB2000).

Dechant, J.A., M.L. Sondreal, D.H. Johnson, L.D. Igl, Goldade, P.A. Rabie, B.R. Euliss, M. Koenen, G. Hammerson, and D.W. Mehlman. 1999. Species Management Abstract: Nelson's Sharp-tailed Sparrow (Ammodramus nelsoni). THE NATURE CONSERVANCY, 4245 North Fairfax Drive, Suite 100, Arlington, VA 2220; downloaded 10/01. 

Greenlaw, J.S. 1993. Behavioral and morphological diversification in sharp-tailed sparrows (Ammodramus caudacutus) of the Atlantic Coast. Auk 110(2):286-303.

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.). The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, D.C.

Montagna, W. 1942. The sharp-tailed sparrows of the Atlantic coast. Wilson Bulletin 54(2):107-120.

U.S. Fish & Wildlife Service. April 1999. Parker River National Wildlife Refuge, Birds. U.S. Fish and Wildlife Service. Unpaginated. Jamestown, ND: Northern Prairie Wildlife Research Center Home Page. (Version 10JUL2001).