Semipalmated Sandpiper Habitat Model
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Draft Date:
March 2001

Species:
Semipalmated sandpiper, Calidris pusilla

Use of Study Area Resources:
Migration. Semipalmated sandpipers use Bay of Fundy and eastern Maine coastal areas as stopover sites to replenish fat reserves during fall migration (Hicklin 1987, Dunn et al. 1988). They also may use muddy shores of inland lakes and wetlands (Pierson et al. 1996). Semipalmated sandpipers breed in North American sub-arctic tundra and winter along the northern and central coasts of South America (Gratto-Trevor 1992, DeGraaf and Rappole 1995).

Habitat Requirements:
Semipalmated sandpipers feed on small fresh- or saltwater invertebrates including amphipods, worms, snails, crustaceans, small bivalves, and insects (Gratto-Trevor 1992). In coastal staging areas, they can be found roosting during high tide on beaches or salt marshes (Hicklin 1997, Pierson et al. 1996), and following the ebbing tide to feed on exposed flats by probing sediments for burrowers or taking surface prey (Harrington 1972 in Gratto-Trevor 1992). Favored habitats include sandy/muddy intertidal flats (Hicklin 1997), the edge where saltmarsh and tidal flat meet (Hayman et al. 1986), and shallow water areas with little vegetation, such as lake edges, marshes, ponds, and lagoons (Gratto-Trevor 1992, DeGraaf & Rappole 1995).

Model:
The habitat models relied on abundance/occurrence information from a Maine Department of Inland Fisheries and Wildlife (MDIFW) shorebird coverage, the Manomet Bird Observatory's International Shorebird Survey (ISS) database for Massachusetts and New Hampshire, and Pierson et al. (1996) for additional inland sites used by black-bellied plovers in Maine. The occurrence information was used to select the general localities used by the species. Environmental data sets (bathymetry and wetland cover type) were used to select areas within those localities likely to have been used. The ISS data specified the observation locations only to the nearest minute, and Pierson's observations also were somewhat general, so all suitable cover types (see table, below) within a 1 km radius of those points were regarded as having the level of use indicated at the observation point.

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 0.5*
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 0.5*
L2US Lake, unconsolidated shore 1.0
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 0.5
E2RS, R1RS Estuarine, tidal river rocky shore
E2SS Estuarine intertidal shrub
E2US, R1US Estuarine, riverine 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 1.0
NOTES *included only if within 1 km of known site with regular draw-downs

Habitat Suitability Scoring: Sites with semipalmated sandpiper occurrences and having any of the suitable landcover types (see table) first were scored according to level of use. If a site had 5 or more birds observed at any time, the suitability index = 1.0; else, if any birds were present, or use was expressed as a narrative (Pierson et al. 1996), the suitability index = 0.5. This value was then multiplied by the landcover score.

Suitable estuarine and marine cover types outside of the observation/occurrence polygons were scored as potential foraging habitats; unconsolidated sediment cover types were rescored 0.2, marsh types were rescored 0.1.

Sources:
DeGraaf, R.M. and J.H. Rappole. 1995. Neotropical Migratory Birds: Natural History, Distribution and Population Change. Comstock Publishing Associates, Ithaca, NY. 676 pp.

Dunn, P.O., T.A. May and M.A. McCollough. 1988. Length of stay and fat content of migrant semipalmated sandpipers in eastern Maine. The Condor 90:824-835.

Gratto-Trevor, C.L. 1992. Semipalmated sandpiper. In A. Poole, P. Stettenhaeim, and F. Gill (eds.) The Birds of North America, No. 6. The Academy of Natural Sciences, Washington D.C.

Hayman, P., J. Marchant and T. Prater. 1986. Shorebirds, an Identification Guide. Houghton Mifflin Co., Boston, MA.

Hicklin, P.W. 1987. The migration of shorebirds in the Bay of Fundy. Wilson Bull. 99(4):540-570.

Hicklin, P. 1997. The Bay of Fundy ecosystem project. Proc. Rim of the Gulf Symposium, Portland, ME.

Pierson, E.C., J E. Pierson and P.D. Vickery. 1996. A Birders Guide to Maine. Down East Books, Camden, ME.