Ruddy Turnstone Habitat Model
go to: USFWS Gulf of Maine Watershed Habitat Analysis
go to: Species Table

Draft Date:
November 2002

Species:
Ruddy turnstone, Arenaria interpres

Use of Study Area Resources:
Migration. Ruddy turnstones breed in the tundra regions of northern North America from Alaska to Greenland, also Europe and Asia (Nettleship 2000). They winter along the eastern Atlantic coast of Europe through northwestern Africa, and both coasts North and Central America.  On the Eastern Seaboard they winter as far north as Massachusetts (Veit and Petersen 1993), but occasionally into Nova Scotia (Nettleship 2000).

Habitat Requirements:
Outside the breeding season, coastal habitats are preferred (Hayman et al.1986). Ruddy turnstones "concentrate at large estuaries, rocky coasts, and mixed pebble and sand beaches, where they feed rapidly, usually in tight groups, flying in unison from one patch to another...  [also found on] mudflats with seaweed debris, mussel beds, and some inland lakeshores or beaches" (Nettleship 2000). They are primarily associated with rocky shores (Johnsgard 1981), and prefer sand and pebble beaches to mud flats (Veit and Petersen 1993). During winter they use protected mudflats with mussel beds, or stony shores with seaweed growth (Hayman et al.1986, Nettleship 2000).

Ruddy turnstones feed opportunistically on intertidal invertebrates (crustaceans, molluscs, marine worms), insects, carrion, small fishes, and even gull and tern eggs (Nettleship 2000).

Wintering and migration habitats are vulnerable to disturbance, contamination, and development.  Staging areas, in particular, are situated in coastal areas with much human activity, or may depend on food resources being depleted by commercial fishing activities (e.g., horseshoe crab fishery in Delaware Bay; Nettleship 2000).

Model:
Sites with known ruddy turnstone 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	0.5
L2RS	Lake, rocky shore
R1UB	Riverine subtidal unconsolidated
Rper	Riverine perennial
E1AB	Estuarine subtidal vegetated
E1UB	Estuarine subtidal unconsolidated bottom
E2AB	Estuarine intertidal algae	0.7
E2EM	Estuarine intertidal emergent
E2RS, R1RS	Estuarine, tidal river rocky shore	1.0
E2SS	Estuarine intertidal shrub
E2US, R1US	Estuarine, riverine intertidal unconsolidated shore	0.7
M1AB	Marine subtidal vegetated
M1UB	Marine subtidal unconsolidated bottom
M2AB	Marine intertidal algae	0.7
M2RS	Marine intertidal rocky shore	1.0
M2US	Marine intertidal unconsolidated shore	0.7
NOTES

Habitat Suitability Scoring: Sites with ruddy turnstone 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 half the nominal score.

Suitable cover types outside of the observation/occurrence polygons were scored 0.2 for rocky shores and 0.1 for unconsolidated substrates.

Sources:

Hayman, P., J. Marchant and T. Prater. 1986. Shorebirds: an Identification Guide to the Waders of the World. Houghton Mifflin Company, Boston, MA. 412pp.

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

Nettleship, D.N. 2000. Ruddy turnstone (Arenaria interpres). In A. Poole and F. Gill (eds.) The Birds of North America, No. 537. The Birds of North America, Inc. Philadelphia, PA.

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