Hudsonian Godwit Habitat Model
go to: USFWS Gulf of Maine Watershed Habitat Analysis
go to: Species Table

Draft Date:
October 2002

Species:
Hudsonian godwit, Limosa haemastica

Use of Study Area Resources:
Migration. The hudsonian godwit breeds in near-coastal sedge marshes and meadows, from southern Alaska to northeastern Manitoba, including Hudson's Bay, and winters in southern South America (Johnsgard 1981). They were regarded as rare until the 1960's, when more comprehensive surveys disclosed significant populations in northern latitudes (Hayman et al. 1986).  The Hudson's Bay population is estimated at about 36,000 birds (United States Shorebird Conservation Plan 2001). During migration they may be locally common at coastal sites in the study area (Veit and Petersen 1993).

Habitat Requirements:
Hudsonian godwits use tidal flats, swamps and streams in their wintering grounds, wade in water to 6" deep, and are believed to feed on worms, insects, molluscs, and crustaceans (Johnsgard 1981). During migration and in winter they use "muddy estuaries, coastal pools, flooded grassland and rice fields, less frequently ...sandflats and beaches" (Hayman et al. 1986).

Model:
Sites with known hudsonian godwit occurrences were scored higher than areas having appropriate cover types but without observation data. We used abundance/occurrence information from a Maine Department of Inland Fisheries and Wildlife (MDIFW) shorebird coverage and the Manomet Bird Observatory's International Shorebird Survey (ISS) database for Maine, Massachusetts and New Hampshire. This occurrence information was used to select the general localities (polygons or buffers around observation points) used by the species. Environmental data sets (bathymetry and wetland cover type) were used to identify areas within those localities likely to have been used. The ISS data specified the observation locations only to the nearest geographic minute. Therefore, all suitable cover types (see table, below) within the MDIFW polygons or within a 1 km radius of the point data were regarded as having the respective levels of use for that observation.   

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
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

Habitat Suitability Scoring: Sites with hudsonian godwit  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 landcover scores were applicable as presented; otherwise, if any birds were present, the landcover values were then multiplied by 0.5.

Suitable cover types outside of the observation/occurrence polygons were scored 0.2.

Sources:

Hayman, P., J. Marchant and T. Prater. 1986. Shorebirds, an Identification Guide. Houghton Mifflin Co., Boston, MA. 412 p.

Johnsgard, P.A. 1981. The Plovers, Sandpipers and Snipes of the World. University of Nebraska Press. Lincoln. 493 pp.

United States Shorebird Conservation Plan 2001, Second Edition. S. Brown, C. Hickey, B. Harrington, and R.Gill, (Eds.). Manomet Center for Conservation Sciences, Manomet, Massachusetts 02345

Veit, R.R. and W.R. Petersen. 1993. Birds of Massachusetts. Massachusetts Audubon Society. 514 p.