Rock Sandpiper
Rock Sandpiper
Calidris ptilocnemis
At a Glance
Very similar to the Purple Sandpiper, replacing it in the west. Spends the winter on coastal rocks, sharing this habitat with other 'rockpipers' like Black Turnstone and Surfbird. Rock Sandpiper is more effectively camouflaged than these birds, and is often very hard to spot against the gray boulders. Although it nests in places on the mainland of Alaska, it seems most numerous on Bering Sea islands such as the Pribilofs and the Aleutians.
All bird guide text and rangemaps adapted from by Kenn Kaufman漏 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Sandpiper-like Birds, Sandpipers
IUCN Status
Least Concern
Habitat
Coasts and Shorelines, Tundra and Boreal Habitats
Region
Alaska and The North, California, Northwest, Western Canada
Behavior
Direct Flight, Hovering, Rapid Wingbeats, Running
Population
140.000
Range & Identification
Migration & Range Maps
Those nesting on Pribilofs and Aleutians are apparently short-distance migrants or permanent residents. Mainland breeders go farther south. Some of those wintering on our west coast south of Alaska probably come from Siberia.
Description
8-9" (20-23 cm). In winter almost identical to Purple Sandpiper, identified by range. Summer adults might suggest Dunlin but larger, with dark gray patch on lower breast (not black patch on belly). Rock Sandpipers nesting on Pribilof Islands are larger and paler than those elsewhere in Alaska.
Size
About the size of a Robin
Color
Black, Brown, Gray, White, Yellow
Wing Shape
Pointed, Short, Tapered
Tail Shape
Rounded, Short, Square-tipped, Wedge-shaped
Songs and Calls
Usually silent; low whistled notes sometimes heard in winter.
Call Pattern
Flat
Call Type
Buzz, Chirp/Chip, Trill
Habitat
Rocky shores; nests on mossy tundra. In winter typically on rocky shores or rock jetties, foraging mostly in zone below high-tide mark, especially on mats of algae or among mussels or barnacles. Breeds on tundra, generally on drier and more barren stretches with sparse cover of lichen, moss, grasses.
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Behavior
Eggs
usually 4. Olive to buff, blotched with brown. Incubation is usually by both sexes, about 20 days. Occasionally only one parent (either one) incubates. If predators threaten nest, adult may perform distraction display, fluttering away as if wing is broken.
Young
may leave the nest within a few hours after hatching. Usually tended by male, rarely by female or by both parents. Young find all their own food. Age at first flight not well known, probably about 3 weeks.
Feeding Behavior
forages by moving about slowly on rocks, or walking on mudflats or tundra. Finds its food visually.
Diet
mostly insects and other invertebrates. Insects may be main part of diet on breeding grounds, but also eats crustaceans, mollusks, marine worms. Unlike most sandpipers, also eats some plant material, including berries, seeds, moss, and algae. On migration and winter, diet is mostly small mollusks, crustaceans, and insects.
Nesting
Male defends territory by flying in wide circle with fluttering wingbeats, giving trilled calls. In aggressive display on ground, male raises one wing. Nest site is on ground on open dry tundra, often on a raised area of lichen or moss. Nest is a deep scrape, usually lined with lichen, leaves, grass. Male begins scrape, female may add some lining.
Conservation
Conservation Status
Numbers wintering in the Pacific Northwest have declined since the 1970s.
Climate Threats Facing the Rock Sandpiper
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.