Sanderling

(Calidris alba) (SAND)

Photographic Identification Guide

Sanderling (Calidris alba) (SAND), a world-wide denizen, is a common fall and winter visitor to southern New England shores. In all plumages, recognize this small sandpiper due to its sturdy, short bill, short legs and rounded body. In winter, it is the palest of our shorebirds.

A relatively common migrant on New England shores historically, SAND has undergone drastic drop-offs in migratory populations in the past 4 to 5 decades. Migrating SAND in spring, along with Ruddy Turnstone (RUTU), Red Knot (REKN) and other shorebird species, depend heavily on a feast of Horseshoe Crab eggs in Delaware Bay. This food resource has been reduced due to human hunting and killing of Horseshoe Crabs for use in medical labs and for fishing bait and pet food. Many of the birds, deprived of a rich food resource, are either unable to complete their migration to the Arctic where they breed, or once there, do not have enough fat reserves to breed successfully.

The State of New Jersey has limited human access to some of the beaches where Horseshoe Crabs come ashore in May to spawn. This has resulted in limited but noticeable reduction in the rate of population decline in affected shorebird populations such as Sanderlings.

In this guide, we cover the features, in order of importance, to look for on these birds. When discussing plumages, we use the terms winter, spring, and summer to refer to northern hemisphere seasons. Because some of these birds spend parts of the year in the northern and southern hemispheres, the correct technical terms for the plumage stages—basic and alternate—help avoid the confusion of seasonal terminology.

visual gallery

species account

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Fig. 1. Sanderling. Winter (basic) plumage. Note pale mantle, plain, whitish face. Point of Pines, Revere, MA. 23 September 2014.
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Fig. 5. Sanderlings. Note halted molt on right-hand bird. Plymouth Beach, Plymouth, MA. 4 May 2018.
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Fig. 6. Sanderling. Spring (alternate) plumage. Sea Rim State park, TX. 7 May 2015.
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Fig. 9. Sanderling juvenile. Winthrop Beach, Winthrop, MA. 30 August 2016.
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Fig. 4. Sanderling. Winter (basic) molting to spring (alternate) plumage. Sea Rim State Park, TX. 7 May 2015.
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Fig. 8. Sanderlings. Molting adult (left) and fresh juvenile (right). Winthrop Beach, Winthrop, MA. 21 September 2021.
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Fig. 14. Comparison of Sanderling and Dunlin, both in winter (basic) plumage. Winthrop Beach, Winthrop, MA. 19 January 2023.
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Fig. 2. Sanderlings. Winter (basic) plumage, roosting. Bolivar Peninsula, TX. 5 November 2019.
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Fig. 3. Sanderlings. Varied stages of molt to spring (alternate) plumage. Bolivar Peninsula, TX. 11 May 2015.
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Fig. 7. Sanderling. Summer (alternate) molting to winter (basic) plumage. Napa Tree Point, RI. 2 August 2017.
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Fig. 10. Sanderlings. Foreground: juveniles in fresh plumage. Background: individual nearly fully molted to winter (basic) plumage. Duxbury Beach, Duxbury, MA. 4 September 2021.
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Fig. 16. Comparison of Sanderlings with Western Sandpiper. Note different distribution of rufous feathers on spring (alternate) plumage birds. Plymouth Beach, Plymouth, MA, 18 May 2019.
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Fig. 13. Comparison of Semipalmated Sandpiper (SESA) and Sanderling (SAND) juveniles. Note size difference, boldly checkered plumage of SAND. Point of Pines, Revere, MA. 23 September 2014.
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Fig. 18. Comparison of molting juvenile Sanderling and molting adult White-rumped Sandpiper. Note similarity in size, browner, less contrasting plumage on White-rump. Plymouth Beach, Plymouth, MA. 23 September 2012.
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Fig. 17. Comparison of Sanderlings and Western Sandpiper. Note thin bill, smaller size and darker, brownish plumage of Western Sandpiper. Avalon, NJ. 23 September 2013.
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Fig. 15. Dunlins and Sanderlings in flight. Note long bill and hooded head and breast on Dunlin versus pure white underparts of Sanderling. Point of Pines, Revere, MA. 20 October 2007.
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Fig. 11. Sanderling juvenile molting to winter (basic) plumage. Nahant Beach, Nahant, MA. 2 September 2016.
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Fig. 12. Sanderlings in flight. Note broad white wing stripes, dark center of tail. Plymouth Beach, Plymouth, MA. 13 August 2019.

The photos in this species account are arranged in this order:

Basic: winter plumage, roughly September to April.

SAND begins its molt to winter (basic) plumage on its high-Arctic breeding grounds. The molt continues while the birds are here in late summer and full basic plumage is attained by early fall, sometimes in September; see Fig. 1, Fig. 2.

Alternate: first spring and summer after hatch year or adult breeding plumage, May to September.

Beginning in spring, winter (basic) feathers on SAND are gradually replaced by alternate feathers; see Fig. 3, Fig. 4, Fig. 5, Fig. 6. In late summer, replacement of alternate feathers to winter (basic) plumage begins; see Fig. 7.

Juvenile: young birds, recently hatched, July to September.

These feathers are acquired on the breeding grounds immediately after the natal down is shed and before the young begin their southbound migration; see Fig. 9. In the fall, juvenile feathers begin to be replaced by winter (basic) plumage.

Size and weight

Female Sanderlings are slightly larger than males and have longer bills.

Body length:

7.7– 8 in. (18–20 cm)

Wingspan:

14.5–16 in. (37–40 cm)

Bill length:

0.9–1.1 in. (24–27 mm)

Weight:

1.7–2.4 oz. (47–66 g)

Calls

Sanderlings emit hard chuck calls when taking flight.

Calls in Stone Harbor, NJ, 2010:

Calls in Titusville, FL, 2014:

Plumage and other characteristics

SAND forages at the edge of the water, following ocean tides in and out. Birds run along the very edge of the tide, stopping occasionally to pick at food.

In spring and late summer, SAND may be dark, with speckled rufous and black plumage; see Fig. 6.

Outside of spring or summer (alternate) plumage, SAND can often be distinguished from other small gray sandpipers by a white “shoulder” and dark feathers at the bend of the wing; see Fig. 1, Fig. 11.

The hallux (rear toe) is lacking from SAND, in contrast to other small sandpipers; see Fig. 2, Fig. 6.

Winter (basic) plumage is pale gray above, pure white below. In this plumage, SAND is the palest of small sandpipers; see Fig. 1, Fig. 2, Fig. 14.

In the spring, a checkered array of rufous-cinnamon and black feathers with broad white margins begins replacing the pale gray mantle feathers. The varieties of plumage at this stage of molt can be bewildering; see Fig. 3.

Spring (alternate) and summer (alternate) are the same plumage; however, as seasons advance, feather margins become worn and the plumage looks different. Full spring (alternate) plumage consists of rufous-cinnamon upperparts and a speckled cinnamon hood over the head, neck and upper breast; see Fig. 5, Fig. 6.

Adults begin to molt to winter (basic) plumage from mid-summer on. Most of the cinnamon and rufous wears off, particularly on the back (mantle). Transitional birds have a warm speckled hood on the head, neck and upper breast and an unevenly checkered black-and-white mantle; see Fig. 7.

By September, most summer (alternate) plumage has been replaced by the evenly gray winter (basic) mantle feathers; see Fig. 8.

When juvenile birds arrive in August, they have the characteristic fresh, evenly patterned look of most young shorebirds. Every feather is the same age, so the back (mantle) feathers have a uniform, repeated, checkered black-and-white pattern. The crown is also streaked black-and-white; the face and neck are white. Smudged buffy streaks may be on the face, shoulders or at the bend of the wings; see Fig. 8, Fig. 9, Fig. 10.

By September, young birds begin to lose their checkered juvenile feathers, which are replaced by pale gray mantle feathers with dark center shafts, characteristic of SAND in winter (basic) plumage; see Fig. 11.

In flight, SAND displays a gray mantle and bold white wing stripe from above; see Fig. 12.

From below, winter SAND in flight displays a completely white underside of body; see Fig. 15.

Sanderling, unlike other small sandpipers, lack a hallux (rear toe); see Fig. 2, Fig. 6. (This feature is not alwys easy to discern.)

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Breeding range, migration, wintering range, habitat

SAND breeding range is circumpolar. In North America, SAND breeds in Arctic regions of Canada, with a small breeding population in Alaska.

Sanderling breeding habitat in Arctic regions is on gentle slopes and ridge tops with access to wet tundra, ponds or lakes.

After the breeding season, Sanderlings disperse south, migrating primarily along oceanic coasts. Preferred habitat during non-breeding seasons is on hard-packed sandy ocean beaches, occasionally on the shores of shallow inland lakes.

During winter, some remain as far north as the coast of Massachusetts, but most winter at more southerly temperate and tropical coasts throughout the world in both northern and southern hemispheres.

In spring, SAND migration routes to Arctic breeding regions vary. On the east coast of North America, migrating SAND is one of several shorebird species that takes advantage, during the middle weeks of May, of the Horseshoe Crab egg banquet in Delaware Bay and off the coast of Cape May, NJ. While there, birds fatten up in advance of their final push to reach their Arctic nesting region. In general, the flight from Delaware Bay to Arctic breeding areas is direct and nonstop.

Foraging Sanderlings are well-known on beaches, where they probe the sand and gobble up small crustaceans and mollusks. They run up and down the beach on whirring legs right along the edge of water as the waves lap in and out during low tide.

At higher tides they roost in dense flocks on higher dunes, sometimes on rock jetties or breakwaters.

Similar species

SAND compared to DUNL

Sanderling (SAND) and Dunlin (DUNL) are nearly identical in body size and shape and seek similar habitats to feed in or roost.

Note the following:

DUNL has a dramatically longer bill than SAND and is a brownish gray on the mantle, vs. silvery gray of SAND.
In winter (basic) plumage, DUNL throat, neck and upper breast are gray, with fine streaks on the sides of the lower breast and belly. SAND underside is pure white from throat to tail; see Fig. 14.
In flight, SAND lacks the conspicuous long bill of DUNL; winter (basic) DUNL has hooded head, throat and neck, in contrast to the pure white underparts of SAND; see Fig. 15.

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SAND compared to SESA

Sanderling (SAND) is much larger than Semipalmated Sandpiper (SESA), with thicker legs and thicker bill.

Note the following:

In spring (alternate) plumage, SAND acquires plumage of highly speckled cinnamon-rufous and black upperparts, head and neck. SESA spring (alternate) mantle plumage consists primarily of brownish-gray feathers with some rufous highlights on the crown.
The juvenile plumage of both SAND and SESA are highly patterned. SESA displays a scaly brown-and-white mantle pattern, whereas SAND mantle is strongly checkered black-and-white; see Fig. 13.
SAND winter (basic) mantle plumage is the palest of grays, compared to the brownish-gray of SESA.

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SAND compared to WESA

Sanderling (SAND) is much larger than Western Sandpiper (WESA), with thicker legs and thicker bill.

Note the following:

The rufous in alternate-plumaged WESA is primarily in patches on the crown, cheeks and scapulars. On alternate-plumaged SAND, cinnamon-rufous and black feathers are speckled evenly on the mantle, neck, face, head and breast; see Fig. 16. Note also webbed toes of WESA in photo.
The juvenile plumage of SAND and WESA is highly patterned. WESA displays a scaly brown-and-white pattern; SAND is strongly checkered black-and-white.
SAND winter (basic) mantle plumage is the palest of grays, compared to the pale brownish-gray of WESA; see Fig. 17.

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SAND compared to WRSA

Sanderling (SAND) and White-rumped Sandpiper (WRSA) and are roughly the same size, though SAND is often rounder and chunkier.

Note the following:

In spring (alternate) plumage, SAND has highly speckled cinnamon-rufous and black upperparts, head, and neck; WRSA is grayish on the back (mantle) with some rufous highlights on the upper scapulars.
Molting juvenile SAND mantle is boldly checkered black-and-white; molting WRSA back (mantle) is scaly gray, brown and white, with a streaked gray hood over the head, neck and upper breast; see Fig. 18.
SAND winter (basic) mantle plumage is the palest of grays, compared to the brownish-gray of WRSA.

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