endemic to a single nation, and breeds in a single state or province

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Alaskan endemic.

Comments: Breeding: Occurs on a variety of coastal lowland tundra or montane subarctic tundra; vegetation is ankle high; seldom found at elevations greater than a few hundred meters above sea level or far inland (Gill et al. 2002); will also nest on disturbed habitats (around airports and on reclaimed/ revegetated land), mostly on Bering Sea Islands (Gill et al. 2002). On Pribilof Islands, breeds on high upland tundra (Nelson 1887, Hanna 1921, Preble and McAtee 1923) while on St. Matthew Island utilizes lowlands often just back from the driftwood lines (Hanna 1921). Associated with forb and forb-sedge tundra, rocky shrub tundra/ uplands, crowberry meadows, sedge meadows, beach ridges and dunes (Gill et al. 2002). Nest site generally in upland heath meadows; most nests placed directly on substrate underlain by moss. Nest sites on the Pribilof Islands had little cover when nests were initiated, but those positioned in forb-sedge tundra were probably well-concealed by the time of hatch (Gill et al. 2002).

Non-breeding: Species is confined to intertidal habitats during all phases of non-breeding period. Postbreeding and molting birds found on rocky and soft substrates. Forms roosts at high-tide adjacent to intertidal areas on exposed rocky, cut bank, and sandspit shorelines, and occasionally on man-made structures (Gill et al. 2002). At northern end of wintering range, generally found on hard substrates. In Cook Inlet, birds are restricted to mud and mixed mud and sand flats (Gill et al. 2002).

Foraging: During breeding season forages mostly on tundra. On Bering Sea islands, may also forage on rocky inter-tidal habitats and on gravel and sandy beaches in surf zone. On Pribilof Islands, birds frequently make foraging flights between inter-tidal areas and snow-free inland habitats. Once birds move to nesting areas and establish territories, forage in pooling water at ice edge of melting lakes, in low wet meadows, on islands of open ground around emerging overwintered standing dead sedge, and over snow-rich wetlands embedded in uplands. During non-breeding period forages in various intertidal habitats (Gill et al. 2002).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Short to intermediate distance migrant between breeding sites on Bering Sea islands and wintering range in Cook Inlet and Southeast Alaska. Migration is both earliest in spring (mid- to late Apr) and latest in fall (Oct-Nov) among northern-breeding shorebirds. Large portions of the population leave breeding grounds to molt at sites 250-300 km away on Alaska mainland before moving to wintering areas (Gill et al. 2002). Most leave breeding grounds by mid-September (Preble and McAtee 1923). Arrival in Cook Inlet not until mid-October (Gill and Tibbitts 1999, Gill et al. 2002). Movements to wintering area likely funneled through Bristol Bay (Gill et al. 2002).

Scale and extent of movements during winter are largely unknown. C. p. ptilocnemis wintering in Cook Inlet regularly move 50-150 km south during periods of severe cold, then return when conditions improve. Southward movements during winter usually occur over one or two weeks (Gill and Tibbitts 1999).

Comments: Forages along rocky shores feeding on crustaceans, small mollusks, insects, and worms. Also eats algae, seeds, and berries.

In Cook Inlet, winter diet consists entirely of the mollusk Macoma balthica. In spring, may feed on herring roe attached to marine vegetation and rocks, and in summer on gonads of beached jellyfish (Gill et al. 2002).

A Beringian shorebird having four recognized subspecies, all with breeding and non-breeding populations confined to Alaska and northeast Asia (Gill and Tibbitts 1999). Often seen in association with black turnstones and surfbirds. This species winters farther north than any North American shorebird.

United States

Rounded National Status Rank: N3B,N3N : N3B: Vulnerable - Breeding, N3N: Vulnerable - Nonbreeding

Rounded Global Status Rank: T2 - Imperiled

Reasons: Subspecies C. p. ptilocnemis is an Alaskan endemic; breeds and winters exclusively in Alaska. Restricted breeding and wintering distribution, small population size (<20,000 individuals), and potential adverse impacts in non-breeding areas are of concern. Habitat within breeding range on Bering Sea islands has been markedly altered by reindeer grazing. Vulnerable to oil contamination, especially on restricted wintering grounds in Upper Cook Inlet.

Comments: Previously placed in genera arquatella, eriola, and tringa. At times has been classified as conspecific with Purple Sandpiper (Calidris maritima); Rock and Purple Sandpipers now generally considered as allospecies within a superspecies group (Gill et al. 2002). There are four recognized races of Rock Sandpiper: C.p. ptilocnemis, the nominate form, which breeds on Bering Sea islands, C.p.tschuktschorum, which breeds in east Siberia and west Alaska, C.p. couesi, which breeds on the Aleutian Islands and in south Alaska, and C.p. quarta, which breeds on the Commander and Kuril Islands (Hayman et al. 1986, Gill et al. 2002).