Nelson's Sharp-tailed Sparrow Habitat
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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).
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.
"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 However, A. nelsoni occurrences from an extensive 1997-1999 Maine survey (MDIFW, Tom Hodgman, unpublished) were in marsh patches as small as about 0.2 ha, within larger marsh complexes fragmented by stream channels.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
|Cover Types||Cover Suitability
(0 - 1 scale)
|Upland deciduous forest|
|Upland coniferous forest|
|Upland mixed forest|
|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|
|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. http://www.npwrc.usgs.gov/resource/literatr/grasbird/nsts/nsts.htm (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; http://www.conserveonline.org/2001/05/m/en/nstsp.doc downloaded 10/01.
Greenlaw, J.S. 1993. Behavioral and morphological diversification in sharp-tailed
sparrows (Ammodramus caudacutus) of the Atlantic Coast. Auk
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. http://www.npwrc.usgs.gov/resource/othrdata/chekbird/r5/Parker.htm (Version 10JUL2001).